Version List

Transceiver module TRX433-10C2 / TRX868-10C2 (Vers. 1.0E) 1 

Version List 

Date Version Description 

20.07.2009 1.0 German version translated into English


Table of contents: 

Description ..................................................................................................................................................... 3 

Features ......................................................................................................................................................... 3 

Applications.................................................................................................................................................... 3 

Family overview radio transceiver.................................................................................................................. 4 

Dimensions .................................................................................................................................................... 5 

Pin description................................................................................................................................................ 5 

General information........................................................................................................................................ 6 

Serial Interface (RS232)............................................................................................................................. 6 

Data mode (MODE Pin = Low) ............................................................................................................... 6 

Configuration mode (MODE Pin = High) ................................................................................................ 6 

Radio transmission ................................................................................................................................. 6 

Frequency selection................................................................................................................................ 6 

RF data rate............................................................................................................................................ 6 

Radio telegram structure ........................................................................................................................ 7 

Transmittion- and receiving buffer .......................................................................................................... 7 

Transmittion buffer (TX-BUF).............................................................................................................. 7 

Receiving buffer (RX-BUF) ................................................................................................................. 7 

Handshake with RTS/CTS...................................................................................................................... 8 

Function RTS ...................................................................................................................................... 8 

Function CTS ...................................................................................................................................... 8 

CRC16 .................................................................................................................................................... 9 

CRC16 off............................................................................................................................................ 9 

CRC16 on............................................................................................................................................ 9 

Fast send ................................................................................................................................................ 9 

Fast send off........................................................................................................................................ 9 

Fast send on........................................................................................................................................ 9 

Examples for different configuration of fast send and CRC16.......................................................... 10 

Example for a continued radio data stream (radio telegram with more than 61 bytes payload) ...... 12 

Example for continued data stream over RS232 .............................................................................. 12 

RSSI of the telegram and no signal condition-RSSI............................................................................. 13 

Recalibration............................................................................................................................................. 14 

Energy-saving mode and characteristics by reset, power up, wake up und sleep .................................. 14 

RSSI (Received Signal Strength Indicator) .............................................................................................. 17 

Power supply............................................................................................................................................ 18 

Data interface with 5V systems ................................................................................................................ 18 

MCLR\ Reset............................................................................................................................................ 18 

Status LED ............................................................................................................................................... 18 

Temperature sensor ................................................................................................................................. 19 

Technical data TRX433-10C........................................................................................................................ 20 

Technical data TRX868-10C........................................................................................................................ 21 

Radio range.................................................................................................................................................. 22 

simplified schematic TRXnnn-10 ................................................................................................................. 23 

Example of use for TRXnnn-10C................................................................................................................. 24 

Frequency table TRX433-10C ..................................................................................................................... 25 

Frequenztabelle TRX868-10C ..................................................................................................................... 26 

Instruction set (Version C2) ......................................................................................................................... 27 

Command structure.................................................................................................................................. 27 

Configuration in the RAM or EEPROM .................................................................................................... 27 

Commands overview version C2.............................................................................................................. 28 

Example of initialization in C .................................................................................................................... 29 

Detailed description of the functions ........................................................................................................ 31 

Functional group READ ........................................................................................................................ 31 

Function group WRITE ......................................................................................................................... 40 

Functional group REPORT ................................................................................................................... 50 

Functional group ERROR ..................................................................................................................... 51 

Factory setting.............................................................................................................................................. 52 

Coding marking of the transceiver module .................................................................................................. 53 

CE declaration of conformity........................................................................................................................ 54


Description 

The transceiver module TRXnnn-10C with integrated microprocessor parameterizes with easy commands 

(frequency, RF data rate etc.) over a serial interface. The data communication occurs over the serial 

interface as well. In the process, the transceiver module does the coding and decoding for the radio 

transmission. Depending on demand, the automatic radio transmission can be adjusted to the current needs 

(e.g. minimal delay, maximal data security etc.). The module can be activated easily over the serial interface 

and offers high control over the data flow. Therefore, you have a powerful tool for easy point-to-point radio 

links, up to complex radio networks on your hands without having to worry about RF-specific problems. With 

those transceivers you get excellent radio ranges. 

Features 

• simple data communication over serial interface. The transceiver module does the coding and 

decoding for the radio transmission. 

• flexible and easy configurable with simple RS232 commands. 

Capable instruction set for lots of communication parameter and for power saving functions. 

• narrow band operation with max. 139 respectively 159 frequencies in a 12.5 kHz channel spacing. 

Adjustable RF data rate from 1.2kbits/s to 19.2kbits/s (with assembling options up to max. 

38.4kbits/s possible). 

• low current consumption and fast setup. Power saving functions, optimized for battery operation. 

• compact and light, ideal for portable units. 

• LED status display can be turned off per command. 

• version without voltage regulator available for battery voltage from 2.4 … 3.6V 

• three pin-compatible versions A, B, C cover different demands. 

The instruction set is extendable on customer request. 

Applications 

• high quality remote control with feedback signal 

• industrial, craft, building automation, safety engineering 

We recommend the Demokit3 for comfortable evaluation or for an easy entrance. With that module, a 

bidirectional serial computer-computer or computer-printer connection can be realized within a few minutes 

or the radio range (without computer) can be tested.


Family overview radio transceiver 

The radio transceivers of the family TRX433 and TRX868 are offered in several designs. Their difference is 

in the software and / or in hardware. 

At the moment, there are three versions A, B and C, which have the following differences: 

Version A Version B Version C 

Data interface RS232 any, transparent RS232 

Configuration over 

RS232 

Sleep, Wake up 

tasks 

Only the most important 

parameter, only possible 

by power up 

delay TX-RX 1 t DATA + tRADIO , 

see timing diagram 

Comprehensive command 

set, configurable during 

operation at any time 

No Yes Yes 

6 t BIT-RADIO 

Jitter +- 1/8 t BIT-RADIO 

Comprehensive command 

set, configurable during 

operation at any time 

t DATA + tRADIO 

see timing diagram 

Error checking CRC16 None With / without CRC16 

Retransmit after 

failure 

Until the data are 

acknowledged correctly 

by the receiver 

No No 

Buffer size TX 2 x 31 bytes Ring buffer, 61 bytes 2 

Buffer size RX 1 x 31 bytes, ring buffer Ring buffer, 61 bytes 2 

Data handshake RTS-CTS, XON-XOFF RTS-CTS 

The three versions cover the demands of different usage as follows: 

Version A is for simple usage instead of cable e.g. between computer and peripheral device where the dead 

time through the transmission path does not matter. Data are checked by the transceiver with regard to 

faults. If faults are detected, data are repeated until correct reception. This version only sends the data when 

the buffer is full or when no further data is on hold during the time of 3ms. Version A and Evalkit3 are ideal 

for testing the radio range. 

Version B is used when the maximal control over the radio channel is necessary or desired. There is 

absolutely no coding or error checking done. The signal which is placed on the transmittion side is released 

transparently with a minimal delay 1:1 by the receiver. The signal has therefore an optimal compatibility to 

any way of coding and radio modules of other producers. 

Version C with a transparent byte mode is used when a short reaction time and at the same time the 

simplest activation is desired. The byte-by-byte incoming data are sent over radio with a short delay so that 

the receiver can start with the serial data output just a few milliseconds after the transmission of the 1 st data 

byte. 

When the error checking is active, the receiver outputs only correctly transmitted data. Without the error 

checking there, the higher-rated application has to take care of that. 

1 tBIT_RADIO : time period for 1 bit with the chosen RF data rate 

2 When the RF data rate is adjusted high enough in proportion to the RS232 baud rate then there occurs a 

continued data flow without a break through the handshake


Dimensions 

0.5mm 24.5mm 

Pin description 

40.0mm 

TRX433-10 

TRX868-10 

front view 

14 13 12 11 10 9 8 7 6 

2 1 

2.54mm 10.16mm 2.54mm 

Lead frame: pins 0.5 x 0.2mm 

Pin Name I/O Description Level Condition 

4.5mm 

1 RF I/O RF- in/out for lambda / 4 antenna (~ 50 Ω) 0 V DC-path to GND 

2 GND RF Signal Ground 

6 V_P O Programming voltage (do not connect) VCC 

7 MCLR\ I Reset input, active low. 3 VCC Normal operation 

8 RSSI O Received Signal Strength Indicator (analog out) 0 V -128 dBm 

9 RTS O RTS handshake 0 V Ready to send 

10 TxD O UART transmit data (digital out) VCC Stop bit or no data 

11 RxD I UART receive data (digital in) VCC Stop bit or no data 

12 

CTS 

MODE 

WKUP 

I 

I 

I 

CTS handshake 

Interface mode (data or configuration) 

Sleep mode: Pin change terminates sleep 

13 V+ Positive supply voltage 

14 GND Ground 

0 V 

0 V 

Clear to send 

Data mode 

3.5 to 6VDC 4 or 

2.4 to 3.6VDC 5 

3 

connect an external reset controller, if supply voltage is not always within specified limits or if voltage 

ramp is slower than 50ms from 0V to 3.5V. 

4 

standard version with internal 3.3V supply voltage regulator (output logic high levels are limited to the 

internal 3.3V supply voltage) 

5 

version without internal voltage regulator (internal supply voltage = V+)


General information 

Serial Interface (RS232) 

There is a serial bidirectional full duplex interface available to communicate with the transceiver module. The 

data are transmitted and the transceiver module is configured over the same interface. You can choose 

between data mode and configuration mode with the MODE pin. 

Data mode (MODE Pin = Low) 

When the transceiver module receives data over the serial interface then those are automatically transmitted 

to all transceivers with the same configurations (frequency, RF data rate etc). Then those transceivers output 

them immediately over the serial interface after a few milliseconds. The baud rate for the RS232transmission 

can be set from 1.2kbaud to 115.2kbaud 6 . 

Configuration mode (MODE Pin = High) 

The transceiver module is configured over the serial interface. There is a comprehensive command set 

available. The last configuration will stay saved in the internal EEPROM if the accordant bit for saving in 

EEPROM is set. The configuration can occur in any baud rate from 1.2kbaud to 115.2kbaud 6 (the baud rate 

is detected automatically in the configuration mode). 

Radio transmission 

In the data mode, all the data which was received by the transceiver module over the serial interface are 

transmitted autonomous via radio. The transceiver module completely does the coding and decoding of the 

radio transmission. However, you can adjust the radio transmission to your own needs with help of a few 

simple commands. The following configurations can be done: 

Frequency selection 

There are 139 frequencies in 433MHz–band respectively 159 frequencies in 868MHz–band available, in 

each case in the 12.5 kHz–channel spacing. The frequency can be chosen irrespectively of the adjusted RF 

data rate. Make sure that on systems with several used frequencies, the frequency separation is at least the 

same as the occupied channels of the adjusted RF data rate (see table 1). This frequency separation has to 

be raised as high as possible for a better range. 

RF data rate 

The RF data rate can be chosen from 1.2kbits/s to 38.4kbits/s 7 according to requirements. The smaller the 

RF data rate is chosen, the higher is the radio range between the transceiver modules. RF data rates > 

19.2kbits/s are possible but they require an accordant dimensioned loop filter respectively a change in 

assembling. Through this change, the sensitivity of the receiver with low RF data rates is reduced. The basic 

model TRXnnn-10C2 is assembled with loop filters for max. 19.2kbits/s. 

Further radio transmission configurations to the chosen RF data rates are made automatically by the 

transceiver modules. These configurations for the different possible RF data rates can be found in table 1. 

RF data rates Coding Modulation FM-deviation IF-bandwidth Occupied 

channels 

1.2 kbit/s 

2.4 kbit/s 

4.8 kbit/s 

9.6 kbit/s 

19.2 kbit/s 

38.4 kbit/s 7 

Manchester GFSK 

Manchester GFSK 

NRZ GFSK 

NRZ GFSK 

NRZ GFSK 

NRZ GFSK 

NRZ GFSK 

NRZ GFSK 

+- 2.025 kHz 

+- 2.025 kHz 

+- 2.025 kHz 

+- 2.025 kHz 

+- 4.050 kHz 

+- 4.950 kHz 

+- 9.900 kHz 

+- 19.80 kHz 

9.6 kHz 

12.3 kHz 

9.6 kHz 

12.3 kHz 

19.2 kHz 

25.6 kHz 

51.2 kHz 

102.4 kHz 

1 x 12.5kHz 

1 x 12.5kHz 

1 x 12.5kHz 

1 x 12.5kHz 

2 x 12.5kHz 

4 x 12.5kHz 

8 x 12.5kHz 

12 x 12.5kHz 

Table 1 RF data rate with corresponding further configurations can be chosen. 

Comment 

433 MHz 

868 MHz 

433 MHz 

868 MHz 

6 

115.2kbaud requires a 16MHz µP clock frequency 

7 

RF data rate > 19.2kbits/s requires a modification of the loop filter, therefore a change in assembling and a 

16MHz µP clock frequency


Radio telegram structure 

For the radio transmission, the actual payloads are embedded in a radio telegram. The transceiver module 

builds the radio telegram and the associated coding and decoding and disburdens the user with that. A 

complete radio telegram is built according to figure 1. 

2ms Startup + 

Preamble 

Syncword 

2ms + 32 bits 24 bits 8 bits 

(opt.) 

Figure 1 structure of the radio telegram 

Functions of the individual blocks in the radio telegram 

LengthField 

DataField 

CRC16 

n x 8/9 bits (depends on fastsend-setting) 16 bits 

(opt.) 

2ms startup: settling time for the transmitter for the reduction of the transient emissions 

Preamble: allows the receiver to level out to the carrier signal of the transmitter 

Syncword: indiales start of the data transmission and conduces therefore to the receiver to synchronize 

LenthField: declares number of bytes payload in the DataField (optional) 

DataField: effective payload 

CDC16: checksum for payload in the data field (optional) 

Postamble: sends for the correct receiving of the last Data bits of the radio telegram 

Every radio telegram has to consist of 2ms Startup + Preamble, Syncword, DataField and Postamble. The 

blocks LengthField and CRC16 are, depending on the chosen configuration, added to the radio telegram as 

well. The duration of the individual blocks depends on the adjusted RF data rate and is calculated out of the 

number of bits multiplied by the bit duration of the adjusted RF data rate. Only the period of the 2ms Startup 

stays constantly 2ms with every RF data rate. 

Transmittion- and receiving buffer 

The transceiver module has a transmittion - and receiving buffer, 61 bytes each, for the serial interface. 

Transmittion buffer (TX-BUF) 

Over RS232 received data are buffered in the transmittion buffer. The space in the transmittion buffer frees 

byte-by-byte as soon as a byte is inserted into its place in the DataField of the radio telegramm. 

Receiving buffer (RX-BUF) 

In the receiving buffer, the over radio received data are buffered until their output over RS232. When the 

function “Output of the telegram-RSSI” respectively “Output of the no signal condition-RSSI” is enabled then 

these RSSI-values are buffered in the receiving buffer in addition to the payloads of the radio telegram. 

Depending on the configuration, there are maximum two additional bytes needed in the receiving buffer per 

radio telegram. The space in the receiving buffer for the receiving of the radio telegram has to be free by the 

time the radio telegram receives the actual payloads from the DataField. The space in the receiving buffer is 

freed byte-by-byte as soon as a byte is output over RS232. 

Postamble 

2 bits


Buffer overflow 

Be careful that the two buffers (transmittion- and receiving buffer) don’t overflow. That can be ensured by 

adhere the right timing or by using the handshake (see paragraph Example of data flow and Handshake with 

RTS/CTS). 

Overflow of the transmittion buffer 

The transmittion buffer has, additionally to its 61 bytes, a 2-byte overflow buffer. So when the transmittion 

buffer is full (61 bytes full) and further data are still transferred over RS232 then max. 2 bytes can be saved 

in the overflow buffer. Those will be transferred in the transmittion buffer as soon as there is space in there. 

When the overflow buffer is full as well then further over the RS232 received data will be rejected. 

Overflow of the receive buffer 

The receiving buffer has, additionally to its 61 bytes, a 2-byte overflow buffer. This buffer is only used for 

saving the RSSI-values in addition to the payload if the function “Output of the telegram-RSSI” respectively 

“output of the no signal condition-RSSI” is enabled and if the whole 61 bytes of the receiving buffer are full 

with the radio telegram. 

When data are received over radio even if the buffer is already full (61 bytes full), then the whole incoming 

radio telegram will be rejected if the CRC16 is on. If the CRC16 is off then the already received data will be 

saved and the rest of the incoming radio telegram will be rejected. 

Handshake with RTS/CTS 

The communication over the RS232-interface can be controlled with help of RTS/CTS to avoid overflowing of 

buffers. RTS and CTS are only used for the handshake when the handshake is activated. When the 

handshake is disabled then the RTS and CTS are ignored. 

Function RTS 

As soon as 61 bytes are saved in the transmittion buffer then the transceiver module stops the receiving of 

data over RS232 by setting the RTS-Pin on high. The user may not send further data over the RS232interface 

to the transceiver module until the RTS-pin changes to low again. The RS232-interface enables 

again (RTS-Pin reset to low) once ≤58 bytes are saved in the transmittion buffer. 

Function CTS 

With an activated handshake, the user can stop the output of data of the transceiver module by setting the 

CTS-Pin to high. The transceiver module doesn’t output any more data over the TxD-Pin until the CTS-Pin is 

set back to low by the user. 

Note 

If the CTS-Pin is used as handshake, don’t send any data to the transceiver module during the high-time of 

the CTS-Pin because these data would be interpreted as configuration data. The CTS-Pin has the double 

function handshake (CTS) and interface mode (MODE). 

Figure 2 shows the cycle of a data communication of 64 bytes with use of the handshake. There, module 1 is 

the transceiver and module 2 is the receiver. Additionally you can see how many bytes are saved in the 

transmittion buffer (TX-BUF) of the sending transceiver module and in the receiving buffer (RX-BUF) of the 

receiving transceiver module. 

module 1 

module 2 

bytes in TX-BUF ... 0........... 1........... ........60......... 61................................................................60.59.58.57.56. 56.55.55.54.53. 53.... ....3......................................................... 2...1...0..................................... ............... 

RS232, RTS-pin 

RS232, RxD-pin 

RF-transmission 

RS232, TxD-pin 

Byte 1 

Byte 2 

Byte 60 

Byte 61 

start RF-transmission 

after 2-3 bytes break 

32 Bit 

Preamble 

+2ms 

Startup 

24 Bit 

SYNC 

Byte 62 

Length 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

Byte 5 

Byte 6 

Byte 7 

Byte 8 

Byte 9 

Byte 10 

Byte 11 

Byte 63 

Byte 64 

Byte 60 

Byte 61 

CRC16 

32 Bit 

Preamble 

+2ms 

Startup 

Byte 1 

Byte 2 

24 Bit 

SYNC 

Byte 3 

Length 

Byte 62 

Byte 63 

Byte 64 

bytes in RX-BUF ... 0......................... ........................................................................................................................................................... .................. 61.........60.........59.........58.........57.........56. 59... 58.......... .........0.... 

Figure 2 data communication with handshake 



Byte 4 

Byte 5 

CRC16 

Byte 6 

Byte 7 

Byte 64


CRC16 

The CRC16 is a 16-Bit check sum which checks the payloads in the DataField for correctnes. If the higher 

application doesn’t check the data then you should definitely use the CRC16. 

CRC16 off 

The radio data are not checked for correctness. The RS232 receives a data byte from the DataField of the 

radio telegram and outputs it immediately. The higher application has to deal with the checking of the data. 

CRC16 on 

The payloads in the DataField are CRC16-checksum-verified and the calculated checksum is included on 

the end of the radio telegram. That means that the data of the receiving transceiver module will only be 

output over RS232 when CRC16 corresponds. By wrong CRC16, the whole radio telegram will be rejected. 

Fast send 

The configuration Fast send decides when the radio transmission of the over the RS232 received payloads 

starts and in which way the radio telegram length is transmitted. 

Fast send off 

The data which were received in one piece over the RS232 are buffered in the transmittion buffer. As soon 

as no further data is received over the RS232 for the time of 2-3 RS232-bytes then the radio transmission 

starts and the current stored payloads in the transmittion buffer are transmitted. The length of the radio 

telegram is therefore defined at the beginning of the radio transmission (in the LengthField, the number of 

bytes of payloads are entered). When further data are received over RS232 during the radio transmission, 

they will be buffered in the transmittion buffer and they’ll build a new radio telegram as soon as the radio 

transmission of the current radio telegram is complete. 

Fast send on 

The radio transmission starts once the first byte is received over RS232 and will not stop until no byte is left 

in the transmittion buffer. Therefore the length of a radio telegram is not known in the beginning of the radio 

transmission. That’s why no LengthField is added to the radio telegram. To label the radio telegram length, a 

bit is added to every payload byte in the DataField which shows the end of the payloads. 

Note 

• Although the radio transmission starts earlier with Fast send than without, one bit is added to every 

payload byte in the DataField for the identification of the radio telegram length. Thereby, a radio telegram 

with fast send on and more than 8 bytes payload gets longer than one without fast send. 

• Due to the fact that Fast send means more computing effort, Fast send can only be used up to a RF data 

rate of 19.2kbits/s (respectively 9.6kbits/s by 8MHz µP clock frequency). 

• The radio telegram length is limited to 61 bytes with Fast send when CRC16 is enabled because the 

receiver has to buffer the whole radio telegram until CRC16 is checked. The user has to make sure that 

the length of the radio telegram is no more than 61 bytes payload. 

• With disabled CRC16 and Fast send on, a radio telegram length with over 61 bytes payload is possible. 

• The pause with the period of 2-3 RS232-bytes for the start of the radio transmission without Fast send 

varies depending on the adjusted configuration. To make sure that the radio transmission really will start 

you should keep a minimum pause of three RS232-bytes.


Examples of data flow 

Following, there are some examples by which you can see the data flow by different configuration of Fast 

send, CRC16, Handshake etc. 

Examples for different configuration of fast send and CRC16 

Refer to the figure for the data flow which depends on the configuration of Fast send and CRC16. Thereby, 

module 1 is used as transceiver and module 2 is used as receiver. Of course several modules with the same 

configuration as the transceiver can receive the data signal. 

module 1 

module 2 




Byte 1 

Byte 2 

Byte 3 

Byte 4 



32 Bit 

Preamble 

+2ms 

Startup 

24 Bit 

SYNC 

Length 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

CRC16 

Figure 3 Dataflow without Fast send with CRC16, RF data rate > RS232-baud rate 

module 1 

module 2 




Byte 1 

Byte 2 

Byte 3 

Byte 4 



32 Bit 

Preamble 

+2ms 

Startup 

24 Bit 

SYNC 

Length 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

Byte 1 

Byte 2 

Byte 1 

Byte 3 

output after first 

received databyte 

Figure 4 Dataflow without Fast send without CRC16, RF data rate > RS232-baud rate 

module 1 

module 2 




Byte 1 

Byte 2 

Byte 3 

Byte 4 



2 

32 Bit 

Byte 

Preamble 

24 Bit 

+2ms Startup 

SYNC 

Figure 5 Dataflow without Fast send without CRC16, RF data rate < RS232-baud rate 

Length 

Byte 1 

Byte 1 

Byte 2 

Byte 3 

Byte 3 

Byte 4 

Byte 4 



Byte 2 

Byte 3 

output after 

checked CRC16 

Byte 4 

Byte 4


module 1 

module 2 




Byte 1 

Byte 2 

32 Bit 

Preamble 

+2ms 

Startup 

Byte 3 

24 Bit 

SYNC 

Byte 4 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

start RF-transmission after 

first received RS232-byte 

CRC16 

Byte 1 

Byte 2 

Byte 3 

output after 

checked CRC16 

Figure 6 Dataflow with Fast send with CRC16, RF data rate > RS232-baud rate 

module 1 

module 2 




Byte 1 

Byte 2 

32 Bit 

Preamble 

+2ms 

Startup 

Byte 3 

24 Bit 

SYNC 

Byte 4 

Byte 1 

Byte 2 

Byte 3 

Byte 4 


after first received RS232-byte 

Byte 1 

Byte 2 

Byte 3 



Figure 7 Dataflow with Fast send without CRC16, RF data rate > RS232-baud rate 

module 1 

module 2 




Byte 1 

Byte 2 

Byte 3 

Byte 4 

2 

32 Bit 

Byte 

Preamble 

24 Bit 

+2ms Startup 

SYNC 

start RF-transmission after 

first received RS232-byte 

Byte 1 

Byte 1 

Byte 4 

Byte 2 

Byte 3 

Byte 3 

Byte 4 



Figure 8 Dataflow with Fast send without CRC16, RF data rate < RS232-baud rate 

Byte 4 

Byte 4


Example for a continued radio data stream (radio telegram with more than 61 bytes payload) 

A continued radio data stream (thus a telegram which isn’t limited to 61 bytes payload) can only be realized 

with Fast send and without CRC16. Also, the RS232-baud rate has to be chosen at least as fast as the RF 

data rate. With these configurations, a continued radio data stream like in figure 9 can be realized. It is also 

apparent in Figure 9 how the CTS pin may prevent the transceiver module from outputting the data via 

RS232 that it received via radio. Also you can see the number of bytes in the transmittion buffer (TX-BUF) of 

the sending transceiver module and the numbers of bytes in the receiving buffer (RX-BUR) of the receiving 

transceiver module. 

module 1 

module 2 

bytes in TX-BUF 





RS232, CTS-pin 

bytes in RX-BUF 

0.... 1.... 2.... 3.... 4.... 5.... 6.... 7.... 8.... 9....10...11...12...12...12...13...13...14...14...15...15... 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

32 Bit 

Preamble 

+2ms Startup 

Byte 5 

Byte 6 

Byte 7 

Byte 8 

Byte 9 

Byte 10 

24 Bit 

SYNC 

Byte 11 

Byte 12 

Byte 13 

Byte 1 

Byte 14 

Byte 15 

Byte 2 

Byte 16 

Byte 17 

Byte 3 

Byte 18 

Byte 19 

Byte 4 

Byte 20 

... 0........................................................................................ 1....0....1....0.... 1....0....1....0... ....0....1....0....1....0....1..........2..........3...2.....2....1...2.1...0..1....0....1....0....1....0.. 

Figure 9 Dataflow with Fast send without CRC16, RS232-baud rate = 2x RF data rate 

Byte 5 

Byte 21 

Byte 121 

60...60...61. 60........59........ 58...59...59...60...60...61.60.... 59........58... 59...59... 

Example for continued data stream over RS232 

With Fast send enabled and CRC16 disabled, a continued data stream can be realized over the RS232interface. 

For that, the RF data rate has to be chosen higher than the RS232-baud rate. In figure 10, a 

continued data stream over RS232 is shown by which the RF data rate is adjusted twice as fast as the 

RS232-baud rate. Further you can see how many bytes are stored in the transmittion buffer (TX-BUF) of the 

sending transceiver module and in the receiving buffer (RX-BUF) of the receiving transceiver module. 

module 1 

module 2 

bytes in TX-BUF 





RS232, CTS-pin 

bytes in RX-BUF 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

...0........... 1...........2...........3........ 2. . 3. 2...1..2.1...0....1...........2...........3......... 2.3..2....1.2...1...0..1...........2...........3..........4.3...2.... 2...1...0.1...........2...........3...........4..3...2..3. 2... 

Byte 1 

Byte 2 

32 Bit 

Preamble 

+2ms 

Startup 

Byte 3 

24 Bit 

SYNC 

Byte 4 

Byte 1 

Byte 5 

Byte 2 

Byte 3 

Byte 4 

Byte 5 

Byte 1 

Byte 6 

Byte 7 

Byte Byte 1 8 

32 Bit 

Preamble 

+2ms 

Startup 

Byte Byte 1 9 

24 Bit 

SYNC 

Byte Byte 1 10 

...0....................................................... 1... 2...3.2..3...4..3.......... 2...........1.......... 0.1...2...3.2..3...4..3.......... 2...........1..........0.1...2...3.2..3...4..3.......... 2...........1...........0.1.... 2... 

Byte 60 


Byte 6 

Byte 7 

Byte 8 

Byte 9 

Byte 10 

Byte 61 

Byte 122 

Byte 123 

Byte 61 


Byte 62 

Byte 62 

Byte 63 


32 Bit 

Preamble 

+2ms 

Startup 

Byte 64 


24 Bit 

SYNC 

Byte 124 

Byte 65 


Byte 125 

Byte 63 

Byte 126 

Byte 66 

Byte 64 

Byte 127 


Byte 11 

Byte 12 

Byte 13 

Byte 14 

Byte 15 

Figure 10 Data stream with Fast send without CRC16, RF data rate = 2x RS232-baud rate 

Byte 2 

Byte 3 

Byte 4 

Byte 5 

Byte 6 

Byte 7 

Byte Byte 1 8 

Byte Byte 1 9 



Byte 65 

Byte 128 

Byte 67 


Byte 66 


Byte 67 

Byte 68 


32 Bit 

Preamble 

+2ms 

Startup 


Byte 68 

Byte 69 


Byte 129 

Byte 69 


Byte 70 

24 Bit 

SYNC 

Byte 130 


Byte 70 


Byte 16 

Byte 71 

Byte 17 

Byte 131 60 

Byte 16 

Byte 21 

Byte 18


RSSI of the telegram and no signal condition-RSSI 

To define the quality of a radio connection, the received sighnal strength indicator (RSSI) of the just received 

radio telegram can be output over RS232 after every received radio telegram. The signal strength will be 

output in dBm in addition to the payloads of the radio telegram in a twos complement. 

The no signal condition - RSSI can be output optionally in addition to the RSSI of the telegram. The RSSIvalue 

which was measured immediately after the radio telegram will be output as a no signal condition - 

RSSI. Out of those two RSSI-values, the signal-noise ratio can be calculated. Of course, the no signal 

condition-RSSI can be read out with the command “READ RSSI current” as well. You can see the output of 

the telegram-RSSI (RSSI TLG) and of the no signal condition-RSSI (RSSI at no signal condition) added to 

the payload in figure 11. 

Note 

When the function “Output of the telegram-RSSI” respectively “Output of the no signal condition - RSSI” is 

enabled, then those RSSI-values are buffered in the receive buffer of the transceiver following the payload 

until they are output over RS232. Depending on the configuration, maximum 2 additional bytes are needed in 

the receive buffer per radio telegram. 

module 1 

module 2 




Byte 1 

Byte 2 

Byte 3 

Byte 4 



32 Bit 

Preamble 

+2ms 

Startup 

24 Bit 

SYNC 

Length 

Byte 1 

Byte 2 

Byte 3 

Byte 4 

Figure 11 Output of the telegram-RSSI and the no signal condition-RSSI 

CRC16 

Byte 1 

Byte 2 

Byte 3 

output after 

checked CRC16 

Byte 4 

RSSI TLG 

RSSI Ruhe


Recalibration 

The VCO has to be recalibrated by a temperature variation of >40°C or by a variation of the supply voltage of 

> 0.25 volt (for version without voltage regulator). It can be calibrated automatically in defined intervals from 

5 to 150min, by temperature differences of more than 20°C or just once manual during the calibration 

command. During the calibration, which normally takes 50ms, no radio communicationl is possible. 

Beginning, end and result will be reported if the module is in the configuration mode. 

There occurs an automatic calibration with every power up. The last calibration stays stored in the RAM 

during the sleep. Therefore the transceiver is ready again pretty fast after the wakeup (by 19.2kbits/s RF 

data rate after 3ms, by 2.4kbits/s RF data rate after 5ms). When the temperatures or the supply voltage can 

change significantly during the sleep then you first have to recalibrate after the wake up. 

Energy-saving mode and characteristics by reset, power up, wake up und sleep 

The RF-part of the transceiver can be enabled and disabled with the command Power-control, as well as 

the LED. Disabled, the current consumption is highly reduced but the processor still stays active and uses 

electricity. 

The sleep command is for battery operated units which are mostly inactive and which may just use electricity 

during the radio communication. Thereby the current consumption can be reduced down to 3µA (version 

without intern voltage regulator) during the sleep. The version with voltage regulator uses ca. 100µA while 

sleeping. During the sleep, the transceiver is inactive but all the configurations and the last calibration remain 

in the RAM. 

High reserve energy is achievable due to the low current consumption during the sleep and the short setuptime 

after a wakeup of 3ms by 19.2kbits/s RF data rate respectively 5ms by 2.4kbits/s RF data rate because 

the average of the current consumption depends almost only on the proportion transmitting time/transmitting 

interval. 

The sleep command disables the RF-part and the LED and stops afterwards the clock of the micro controller. 

The behavior during the sleep as well as the behavior after a wakeup can be defined with the command 

parameter WKUP_mode of the sleep command. The timer for automatic recalibration is paused during the 

sleep. 

The WKUP-Pin has to be on its sleep-level (high or low) before the sleep but at the latest 50µs after the 

answer to the sleep command. Afterwards, the change in level automatically activates an immediate 

wakeup. 

The command power up mode is similar to the sleep command. The sleep command is performed 

immediately, the command power up mode doesn’t affects until the next power up. The transceiver can be 

configured with PWUP_mode so that it automatically changes to the sleep mode after the power up until it’s 

awoken and reconfigured from outside. This is important in battery operations so that the radio module 

doesn’t get active autonomously after a battery change and discharges the battery unnoticed. 

The sleep mode finishes through a pinchange on the WKUP-Pin. Thereby, the program either continues 

where it was interrupted by the sleep-command or there is an internal reset whereat a complete re-start 

occurs. When the transceiver is in the configuration mode (MODE-Pin = High) then it shows by “REPORT 

READY” on the RS232 that the microcontroller on the transceiver is ready. Alternatively, the RTS-Pin can be 

supervised. The RTS-Pin goes back to high after the sleep-command. The RTS-Pin is set back to low as 

soon as the transceiver is ready again after a wakeup (see figure 12 and 13).


RTS-pin 

MODE-pin and 

WKUP-pin resp. 



0B0H 

020H 

sleepcommand 

change to 

config-mode 

021H 

answer 

(only sent if still 

in config-mode) 

020H 

021H 

enter sleep 

030H 

wakeup (pinchange 

on WKUP-pin) 

max. 50us for pinchange, otherwise interpreted as wakeup 

001H 

ready after wakeup 

(only sent in config-mode) 


Figure 12 Sleep and wake up with configuration mode after wake up 

RTS-pin 

MODE-pin and 

WKUP-pin resp. 



0B0H 

020H 

sleepcommand 

change to 

config-mode 

021H 

answer 

(only sent if still 

in config-mode) 

020H 

021H 

enter sleep 

030H 

wakeup (pinchange 

on WKUP-pin) 

Figure 13 Sleep and wakeup with data mode after wake up 

001H 



(suppressed because in data-mode) 

The transceiver module will report after ca. 175ms with a ready signal over RS232 after a power up if the 

transceiver module is in the configuration mode. A negative edge on the RTS-Pin can be used alternatively 

to it as a ready signal (see figure 14 respectively figure 15). 

VCC 

RTS-pin 

MODE-pin 


VCC on 

change to config-mode 

030H 

000H 

ready ca. 175ms 

after powerup 

ready ca. 175ms after powerup 

(only sent in config-mode) 

Figure 14 Powerup with transceiver module in configuration mode


VCC 

RTS-pin 

MODE-pin 


VCC on 

stay in data-mode 

Figure 15 Powerup with transceivermodul in data mode 

030H 

000H 

ready ca. 175ms 

after powerup 

ready ca. 175ms after powerup 

(suppressed because in data-mode) 

Note 

• Pay attention to the paragraph supply voltage and MCLR/Reset whenever the supply switches! 

• The most capacity of battery can generally be saved with the sleep-function. We recommend using the 

sleep-function instead of switching the supply.


RSSI (Received Signal Strength Indicator) 

There is a voltage on pin 8 (RSSI) which is directly proportional to the RF - field strength. The transceiver 

scans the field strength every 3ms and outputs the RSSI-value as analogue voltage to pin 8. 

The voltage on the RSSI-pin follows this equation: 

Urssi 

1.5 * 3.3V 

PRF [dBm] = − 128 + * 127 

Zero-point by -128 dBm, Slope: 25.7dB/V, Measurement range -120…-60 dBm 

The RSSI-pin shows an internal resistance of ca. 10kΩ 

RSSI characteristic 

-140 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 

Phf [dBm] 

Figure 16 Tension on RSSI-pin 

PRF can be read out digitally as a RSSI value with the command “READ RSSI current”, whereat the value is 

output directly in the twos complement in the unit dBm 

Examples: PRF = -128 dBm makes a RSSI of 128dec respectively 080H (under the noise floor) 

PRF = -120 dBm makes a RSSI of 136dec respectively 088H 

PRF = -110 dBm makes a RSSI of 146dec respectively 092H 

PRF = -100 dBm makes a RSSI of 156dec respectively 09CH 

PRF = -60 dBm makes a RSSI of 196dec respectively 0C4H (saturation limit) 

The maximal value of the RSSI will be saved by the transceiver (peak hold) and can be read out as well with 

the command “READ RSSI peak” as well. Every read operation of the RSSI peak initializes thereby the 

maximal value so that the maximal value represents the period between two read operations. The RSSI 

peak is initialized right after a sleep as well. 

The RSSI current and the RSSI peak go back to -128dBm during transmission 

3.50 

3.00 

2.50 

2.00 

1.50 

1.00 

0.50 

0.00


Power supply 

The radio transceiver with the voltage regulator needs a good supply voltage with minimum 3.5V and a ripple 

of < 10mVpp. The power amplifier is directly located on the input side of the supply voltage. The 

transmission power is therefore to a minor degree dependant on supply voltage. When the supply is 

switched then the voltage has to fall back to 0V after disabling it before you can enable it again. The supply 

voltage has to rise from 0V to 3.5V during max 50ms so that the integrated microcontroller starts correctly. 

The voltage can never fall under 3.3 Volt, not even momentary. If this can’t be guaranteed then the supply 

has to be supervised with a voltage detector. As soon as it falls under ca. 3.3V, the input MCLR\ has to be 

pulled down. See application example with Demokit3. 

The radio transceiver without voltage regulator can operate from 2.4V to 3.6V. Keep a ripple of 3.3Volt (for standard TRX with 3.3V 

internal voltage regulator). The trip voltage can be reduced down to 2.3V by versions without a voltage 

regulator and a reduced µP clock frequency. 

When you follow the under the paragraph Power supply listed points then there is no external voltage 

detector necessary. 

After a reset on MCLR\Reset input, the transceiver normally needs 75ms to the output of the ready signal 

because the transceiver is calibrated and configured automatically after a reset. The ready signal will only be 

output if the module is in the configuration mode. 

Status LED 

The status of the transceiver-LED is defined by the command power-control. When that command 

accomplished with a set Bit7 then the LED will enable or disable by a powerup accordingly. 

After a sleep-command the LED is always turned off and after the wakeup the LED is always set back to the 

status it had before the sleep.


Temperature sensor 

The transceiver module has an internal temperature sensor. The current temperature can be read by the 

command “READ temperature”. The value range is in between -40°C to +115°C. The temperature is 

actualized every 5s, no matter how often it is read. 

Note 

The 5s-timer for the actualization of the temperature is stopped during the sleep. After the sleep, the 

temperature which was read before the sleep can therefore be displayed for 5s. This temperature can differ 

from the current temperature by a long sleep-time.


Technical data TRX433-10C 

Frequency range 433.0625.... 434.7875 MHz (12.5 kHz channel spacing) 

RF data rate 

Possible parameterization 

of the RF data rate with the 

corresponding fixed 

configuration. 

Coding Occupied 

channel 

IF-bandwidth FM-Deviation 

(Standard version up to 

19.2kbits/s 8 1.2 kbit/s 

2.4 kbit/s 

4.8 kbit/s 

) 

9.6 kbit/s 

19.2 kbit/s 

38.4 kbit/s 8 

Manchester 1 x 12.5 kHz 

NRZ 1 x 12.5 kHz 


9.6 kHz 

9.6 kHz 

19.2 kHz 

+- 2.025 kHz 

+- 2.025 kHz 

+- 4.050 kHz 

NRZ 

NRZ 

NRZ 

4 x 12.5 kHz 

8 x 12.5 kHz 

12 x 12.5 kHz 

25.6 kHz 

51.2 kHz 

102.4 kHz 

+- 4.950 kHz 

+- 9.900 kHz 

+- 19.80 kHz 

-120 dBm with RF data rate = 1.2kbit/s 

Receiver sensitivity by 

different parameterization 

(50 Ohm / BER = 1E-3) 

-118 dBm 

-115 dBm 

-113 dBm 

-110 dBm 

-106 dBm 

with RF data rate = 2.4kbit/s 




with RF data rate = 38.4kbit/s 8 

Frequency tolerance 

± 5ppm standard (Temp. -10°C ... +60°C) 

± 2ppm optional (Temp. -10°C ... +60°C) 

Transmission power 

+12 dBm, supply 5.0 V 


Modulation GFSK 

Radio range by 

free sight 9 

2000m with RF data rate = 1.2kbit/s 

efficient instruction set 

supports functions like: 

Power-control, defines behavior by Power up, sleep, standby 

calibration, RSSI-output, read module temperature, read and write register, 

direct EEPROM-access (read, write), 

Serial number, Hardware, Software version etc. 

serial over RS232 with TTL level, 8 Data bits, 1 Stop bit, no parity 

baud rates: 1.2 / 2.4 / 4.8 / 9.6 / 19.2 / 38.4 / 57.6 / 115.2 

Data interface 

10 kbaud 

automatic baud rate detection on configuration 


61 bytes transmittion buffer and receive buffer 

supply 

3.5 to 6 V DC not stabilized, Ripple


Technical data TRX868-10C 

Frequency range 868.0125.... 869.9875 MHz (12.5 kHz channel spacing) 

RF data rate 

Possible parameterization 

of the RF data rate with the 

corresponding fixed 

configuration 

coding Occupied 

channels 

IF-bandwidth FM-Deviation 

(Standard version up to 

19.2kbits/s 11 1.2 kbit/s 

2.4 kbit/s 

4.8 kbit/s 

) 

9.6 kbit/s 

19.2 kbit/s 

38.4 kbit/s 11 

Manchester 1 x 12.5 kHz 



9.6 kHz 

9.6 kHz 

19.2 kHz 

+- 2.025 kHz 

+- 2.025 kHz 

+- 4.050 kHz 

NRZ 

NRZ 

NRZ 

4 x 12.5 kHz 

8 x 12.5 kHz 

12 x 12.5 kHz 

25.6 kHz 

51.2 kHz 

102.4 kHz 

+- 4.950 kHz 

+- 9.900 kHz 

+- 19.80 kHz 

Receiver sensitivity(50 Ohm -115 dBm 

/ BER = 1E-3) 

With RF data rate= 1.2kbit/s 

Frequency tolerancee 

± 5ppm standard (Temp. -10°C ... +60°C) 

± 2ppm optional (Temp. -10°C ... +60°C) 

Transmission power 


+ 8 dBm, supply 3.5 V 

Modulation GFSK 

Radio range 

by free sight 12 

1200m with RF data rate = 1.2kbit/s 

efficient instruction set 

supports functions like: 

Power-control, defines behavior by Power up, sleep, standby 

calibration, RSSI-output, read module temperature, read and write register, 

direct EEPROM-access (read, write), 

Serial number, Hardware, Software version etc. 

serial over RS232 wit TTL level, 8 Data bits, 1 Stop bit, no parity 

baud rates: 1.2 / 2.4 / 4.8 / 9.6 / 19.2 / 38.4 / 57.6 / 115.2 

Data interface 

13 kbaud 

automatic baud rate detection on configuration 


61 bytes transmittion buffer and receive buffer 

supply 

3.5 to 6 V DC not stabilized, Ripple


Radio range 

The radio range depends on several conditions, which depend on the actual location. 

Most important factors are: The height of the antenna above ground, electromagnetically noise near the 

receiver (from PC’s, monitors etc.), other radio transmittions, type of ground, transmittions within the same 

frequency band on adjacent channels. 

Under normal conditions, with a Demokit3 by 433MHz and the lowest RF data rate, an operating distance of 

over 4km was measured in hilly area. Therefore the stated values are rather conservative. 

When the maximal ranges in the open country are important then we recommand the 433MHz frequency 

band. When there is already a system with 433MHz used on the actual location then you might have higher 

ranges with the 868MHz than with the 433MHz. 

The in the technical data indicated range is conservative and measured with the Demokit3 in a hilly area.


simplified schematic TRXnnn-10 

VCC_IN 

CTS 

RxD 

TxD 

RTS 

R4 

7 8 

5 

6 

3 

4 

1 

2 

F1 

1 

7 

8 

9 

3 

4 

5 

6 10 

VCC 

330R 

47R / 100p 

C35 

RSSI 

R1 

100n 

VCC 

10k 

C38 

100n 

GND 

TP14 

V+ 

TP13 

CTS 

TP12 

RxD 

TP11 

TxD 

TP10 

RTS 

TP9 

R2 

RSSI 

TP8 

TP7 

100R 

MCLR 

V_P 

TP6 

VCC 

2 

RF-part with CC1020 

16 

15 

6 

5 

VSS 

VSS 

R11 

10k 

VDD 

VDD 

CTS 

RTS 

PCLK 

PSEL 

14 

13 

12 

11 

RB7/T1OSI 

RB6/T1OSO/T1CKI 

RB5 

RB4/PGM 

RA5/MCLR/THV 

4 

MCLR 

R12 

C34 

10n 

100R 

PCLK 

PSEL 

10 

9 

8 

7 

RA4/T0CKI/CMP2 

3 

RSSI 

TxD 

RxD 

DCLK 

LOCK 

DCLK 

RB3/CCP1 

RB2/TX/CK 

RB1/RX/DT 

INT/RB0 

TP2 

GND 

DIO 

PDIO 

LED 

SDA 

2 

1 

20 

19 

TP1 

DIO 

PDIO 

RA3/AN3/CMP1 

RA2/AN2/VR 

RA1/AN1 

RA0/AN0 

ANT 

RF 

RA6/OSC2/CLKOUT 

17 

Y2 

RA7/OSC1/CLKIN 

18 

JMP1 

n.f.(4k7) 

Vers. TRXxxx-10-xx : 16MHz 

Vers. TRXxxx-11-xx : 8MHz 

U3 

PIC16LF648A-I/SS 

R13 

330R 

V_PA VCC 

R15 

47k 

LED1 

KM-27SRD-09 

R16 

Standard: U5 fitted, R16 not fitted 

Optional: U5 not fitted, R16 fitted 

n.f. (0R) 

U5 

LP2980IM5-3.3 

L9 

5 

Vout 

Vin 

1 

VCC_IN 

On/Off 

3 

C36 

10u/10V 

N/C 

GND 

C37 

100n 

TRX433-xx-xx / TRX868-xx-xx 

4 

2 

Title: 

Processor-part with PIC16LF648A 

File: TRX-Simplified 1.5.SchDoc 

Date: 26.02.2009 REV 1.5 Sheet 1 of 1


Example of use for TRXnnn-10C 

VCC 

C1 

Levelshift necessary, if levels are not 100% compatible 

100n 

MOD1 

VDD 

3.3V logic levels 5V logic levels 

on Transceiver side on controller side 

VSS 

C2 

10u/10V 

VCC 

14 

GND 

13 

V+ 

WAKEUP / MODE / CTS 

12 

Y1 

5V logic output 

R1 1k 

WKUP / MODE / CTS 

OSC1 

5V logic output 

TxD 

R2 1k 

11 

RxD 

OSC2 

3.3V-logic compatible input 

RxD 

10 

TxD 

8MHz 

3.3V-logic compatible input 

RTS 

9 

RTS 

analog input 

RSSI 

8 

RSSI 

RESET 

7 

MCLR 

6 

V_P 

Microcontroller 

U1 

R4 

2 

1 

VCC VDD RES 

VCC 

3 

C3 10k 

VSS 

10n 

S-80833CNMC 

reset level 3.3V 

2 

GND 

1 

RF 

J1 MCX/BNC 

TRX433/868-10C 

VCC 

U2 LM7805 

VI VO 

+Supply 

C6 

10u/10V 

C5 

100n 

GND 

C4 

330n 

TRX433/868-10C 

Title: 

Application example 

File: Application 10C_V1.SCHDOC 

Date: 16.02.2009 REV 1.0 Sheet 1 of 1


Frequency table TRX433-10C 

1 433.0625 MHz 36 433.5000 MHz 71 433.9375 MHz 106 434.3750 MHz 

2 433.0750 MHz 37 433.5125 MHz 72 433.9500 MHz 107 434.3875 MHz 

3 433.0875 MHz 38 433.5250 MHz 73 433.9625 MHz 108 434.4000 MHz 

4 433.1000 MHz 39 433.5375 MHz 74 433.9750 MHz 109 434.4125 MHz 

5 433.1125 MHz 40 433.5500 MHz 75 433.9875 MHz 110 434.4250 MHz 

6 433.1250 MHz 41 433.5625 MHz 76 434.0000 MHz 111 434.4375 MHz 

7 433.1375 MHz 42 433.5750 MHz 77 434.0125 MHz 112 434.4500 MHz 

8 433.1500 MHz 43 433.5875 MHz 78 434.0250 MHz 113 434.4625 MHz 

9 433.1625 MHz 44 433.6000 MHz 79 434.0375 MHz 114 434.4750 MHz 

10 433.1750 MHz 45 433.6125 MHz 80 434.0500 MHz 115 434.4875 MHz 

11 433.1875 MHz 46 433.6250 MHz 81 434.0625 MHz 116 434.5000 MHz 

12 433.2000 MHz 47 433.6375 MHz 82 434.0750 MHz 117 434.5125 MHz 

13 433.2125 MHz 48 433.6500 MHz 83 434.0875 MHz 118 434.5250 MHz 

14 433.2250 MHz 49 433.6625 MHz 84 434.1000 MHz 119 434.5375 MHz 

15 433.2375 MHz 50 433.6750 MHz 85 434.1125 MHz 120 434.5500 MHz 

16 433.2500 MHz 51 433.6875 MHz 86 434.1250 MHz 121 434.5625 MHz 

17 433.2625 MHz 52 433.7000 MHz 87 434.1375 MHz 122 434.5750 MHz 

18 433.2750 MHz 53 433.7125 MHz 88 434.1500 MHz 123 434.5875 MHz 

19 433.2875 MHz 54 433.7250 MHz 89 434.1625 MHz 124 434.6000 MHz 

20 433.3000 MHz 55 433.7375 MHz 90 434.1750 MHz 125 434.6125 MHz 

21 433.3125 MHz 56 433.7500 MHz 91 434.1875 MHz 126 434.6250 MHz 

22 433.3250 MHz 57 433.7625 MHz 92 434.2000 MHz 127 434.6375 MHz 

23 433.3375 MHz 58 433.7750 MHz 93 434.2125 MHz 128 434.6500 MHz 

24 433.3500 MHz 59 433.7875 MHz 94 434.2250 MHz 129 434.6625 MHz 

25 433.3625 MHz 60 433.8000 MHz 95 434.2375 MHz 130 434.6750 MHz 

26 433.3750 MHz 61 433.8125 MHz 96 434.2500 MHz 131 434.6875 MHz 

27 433.3875 MHz 62 433.8250 MHz 97 434.2625 MHz 132 434.7000 MHz 

28 433.4000 MHz 63 433.8375 MHz 98 434.2750 MHz 133 434.7125 MHz 

29 433.4125 MHz 64 433.8500 MHz 99 434.2875 MHz 134 434.7250 MHz 

30 433.4250 MHz 65 433.8625 MHz 100 434.3000 MHz 135 434.7375 MHz 

31 433.4375 MHz 66 433.8750 MHz 101 434.3125 MHz 136 434.7500 MHz 

32 433.4500 MHz 67 433.8875 MHz 102 434.3250 MHz 137 434.7625 MHz 

33 433.4625 MHz 68 433.9000 MHz 103 434.3375 MHz 138 434.7750 MHz 

34 433.4750 MHz 69 433.9125 MHz 104 434.3500 MHz 139 434.7875 MHz 

35 433.4875 MHz 70 433.9250 MHz 105 434.3625 MHz 

Note 

The frequency channel of two individually operating transceivers must differ at least the amount of channels 

occupied by the selected RF-mode, in order that the spectrums of the two transceivers do not overlap. 

Example: By the configuration with a RF data rate of 9.6kbit/s (see paragraph RF data rate), four channels 

will be occupied. Therefore other transceivers have to differ at least 4 channels when they work with identical 

communication configuration. 

The higher the difference in channels is the better is the operating range with multiple transceivers active at 

the same time.


Frequenztabelle TRX868-10C 

1 868.0125 MHz 41 868.5125 MHz 81 869.0125 MHz 121 869.5125 MHz 

2 868.0250 MHz 42 868.5250 MHz 82 869.0250 MHz 122 869.5250 MHz 

3 868.0375 MHz 43 868.5375 MHz 83 869.0375 MHz 123 869.5375 MHz 

4 868.0500 MHz 44 868.5500 MHz 84 869.0500 MHz 124 869.5500 MHz 

5 868.0625 MHz 45 868.5625 MHz 85 869.0625 MHz 125 869.5625 MHz 

6 868.0750 MHz 46 868.5750 MHz 86 869.0750 MHz 126 869.5750 MHz 

7 868.0875 MHz 47 868.5875 MHz 87 869.0875 MHz 127 869.5875 MHz 

8 868.1000 MHz 48 868.6000 MHz 88 869.1000 MHz 128 869.6000 MHz 

9 868.1125 MHz 49 868.6125 MHz 89 869.1125 MHz 129 869.6125 MHz 

10 868.1250 MHz 50 868.6250 MHz 90 869.1250 MHz 130 869.6250 MHz 

11 868.1375 MHz 51 868.6375 MHz 91 869.1375 MHz 131 869.6375 MHz 

12 868.1500 MHz 52 868.6500 MHz 92 869.1500 MHz 132 869.6500 MHz 

13 868.1625 MHz 53 868.6625 MHz 93 869.1625 MHz 133 869.6625 MHz 

14 868.1750 MHz 54 868.6750 MHz 94 869.1750 MHz 134 869.6750 MHz 

15 868.1875 MHz 55 868.6875 MHz 95 869.1875 MHz 135 869.6875 MHz 

16 868.2000 MHz 56 868.7000 MHz 96 869.2000 MHz 136 869.7000 MHz 

17 868.2125 MHz 57 868.7125 MHz 97 869.2125 MHz 137 869.7125 MHz 

18 868.2250 MHz 58 868.7250 MHz 98 869.2250 MHz 138 869.7250 MHz 

19 868.2375 MHz 59 868.7375 MHz 99 869.2375 MHz 139 869.7375 MHz 

20 868.2500 MHz 60 868.7500 MHz 100 869.2500 MHz 140 869.7500 MHz 

21 868.2625 MHz 61 868.7625 MHz 101 869.2625 MHz 141 869.7625 MHz 

22 868.2750 MHz 62 868.7750 MHz 102 869.2750 MHz 142 869.7750 MHz 

23 868.2875 MHz 63 868.7875 MHz 103 869.2875 MHz 143 869.7875 MHz 

24 868.3000 MHz 64 868.8000 MHz 104 869.3000 MHz 144 869.8000 MHz 

25 868.3125 MHz 65 868.8125 MHz 105 869.3125 MHz 145 869.8125 MHz 

26 868.3250 MHz 66 868.8250 MHz 106 869.3250 MHz 146 869.8250 MHz 

27 868.3375 MHz 67 868.8375 MHz 107 869.3375 MHz 147 869.8375 MHz 

28 868.3500 MHz 68 868.8500 MHz 108 869.3500 MHz 148 869.8500 MHz 

29 868.3625 MHz 69 868.8625 MHz 109 869.3625 MHz 149 869.8625 MHz 

30 868.3750 MHz 70 868.8750 MHz 110 869.3750 MHz 150 869.8750 MHz 

31 868.3875 MHz 71 868.8875 MHz 111 869.3875 MHz 151 869.8875 MHz 

32 868.4000 MHz 72 868.9000 MHz 112 869.4000 MHz 152 869.9000 MHz 

33 868.4125 MHz 73 868.9125 MHz 113 869.4125 MHz 153 869.9125 MHz 

34 868.4250 MHz 74 868.9250 MHz 114 869.4250 MHz 154 869.9250 MHz 

35 868.4375 MHz 75 868.9375 MHz 115 869.4375 MHz 155 869.9375 MHz 

36 868.4500 MHz 76 868.9500 MHz 116 869.4500 MHz 156 869.9500 MHz 

37 868.4625 MHz 77 868.9625 MHz 117 869.4625 MHz 157 869.9625 MHz 

38 868.4750 MHz 78 868.9750 MHz 118 869.4750 MHz 158 869.9750 MHz 

39 868.4875 MHz 79 868.9875 MHz 119 869.4875 MHz 159 869.9875 MHz 

40 868.5000 MHz 80 869.0000 MHz 120 869.5000 MHz 

Note 

The frequency channel of two individually operating transceivers must differ at least the amount of channels 

occupied by the selected RF-mode, in order that the spectrums of the two ransceivers do not overlap. 

Example: By the configuration with a RF data rate of 9.6kbit/s (see paragraph RF data rate), four channels 

will be occupied. Therefore other transceivers have to differ at least 4 channels when they work with identical 

communication configuration. 

The higher the difference in channels is the better is the operating range with multiple transceivers active at 

the same time.


Instruction set (Version C2) 

To configure the transceiver you have to set the MODE-Pin high. Thereby, the transceiver is set into the 

configuration mode and can be configured over the serial interface (Pin 10, TxD and Pin 11, RxD). 

The serial data type is N, 8, 1 (no parity, 8 data bits, 1 stop bit). The baud rate can be chosen freely in the 

configuration mode because the transceiver detects following baud rate automatically: 1.2kBaud, 2.4kBaud, 

4.8kBaud, 9.6kBaud, 19.2kBaud, 38.4kBaud, 57.6kBaud and 115.2kBaud (115.2kBuad requires a 16MHz 

µP clock frequency). 

Command structure 

A command is always made out of 3 bytes: 

Command byte 1 Command byte 2 Command byte 3 

Starting signal [0B0H] Function [00H…0FFH] Parameter or level [00H…0FFH] 

A transceiver will acknowledge a correct received command with an answer within 2ms (respectively 10ms 

by commands that are stored in EEPROM) if the transceiver is still in configuration mode at the time of the 

answer (MODE-pin on high). The answer is mostly out of two bytes but can include more data, depending on 

the command: 

Answer byte 1 Answer byte 2 Answer byte 3…..n 

Function respectively 

echo of command byte 2 

Value [00H…0FFH] Value [00H…0FFH] 

number of bytes depends on function 

Starting signal 

The starting signal marks the beginning of a command frequency and has to have the value 0B0H. 

Notes: 

• The three bytes have to be transmitted to the transceiver within max. 200ms so that a command is 

identified as such. 

• When a transceiver doesn’t recognize a valid command or recognizes a command with a wrong 

parameter then it returns an error code in the used baud rate. See paragraph error code. 

Configuration in the RAM or EEPROM 

The transceiver starts with the in the EEPROM saved configuration (RS232, baud rate, radio frequency, RF 

data rate etc.) in case of receiving the following event: 

• Power up 

• MCLR\ Reset 

• Wakeup after sleep when Reset is configured after sleep 

Afterwards, any parameter can be changed with the WRITE-function. The change is activated immediately 

after the command. 

Is the Bit7 of the function (Byte 2) set in the WRITE-commands 08H...1FH, then the configuration is saved in 

the RAM and additionally stored permanently in the EEPROM. When the Bit7 is deleted, then the 

configuration is only saved in the RAM and isn’t available anymore after a power up. 

Bit7 isn’t important to all the other commands (outside 08...1FH) and it is therefore ignored. 

The answer to a command is always sent back with a deleted Bit7, no matter if Bit7 was set or not in the sent 

command. 

Important notice: The EEPROM has a limited number of 100’000 write cycles per parameter. Therefore the 

often changing parameters (e.g. frequency change by frequency – hopping systems) may only be stored in 

the RAM.


Commands overview version C2 

The functions are divided into the groups READ, WRITE, REPORT and ERROR. 

functional group 

READ 

WRITE 

Only to 

RAM if 

Bit7=0 in 

Byte2 

To RAM 

and 

EEPROM 

if Bit7=1 

of Byte2 

Byte2 is 

identical 

with Byte3 

of the 

according 

READfunction 

Byte 2 

Bit0...6 

Command or function Byte3 Description Answer (example Numbe 

r of 

bytes 

00H Software version 00H, 02H, 28H, 07H 4 

01H Software type 00H, 03H 2 

02H Instruction set version 00H, 02H 2 

03H Hardware version 00H, 0AH 2 

04H Frequency version 00H, 01H 2 

00H Internal constants 

01H Measurement 

02H Configuration 

(from EEPROM) 

Note: 

The current 

configuration in the RAM 

can differ from the 

configuration in the 

EEPROM when the 

WRITE-command is only 

saving in the RAM! 

03H EEPROM register 00H- 

FFH 

04H – 

07H 

Reserved for future 

command extensions 

08H Frequency RX+TX 01H- 

9FH 

09H Frequency RX 01H- 

9FH 

0AH Frequency TX 01H- 

9FH 

0BH RF data rate 00H- 

05H 

0CH RS232-baud rate 00H- 

07H 

0DH Power up mode 00H- 

25H 

0EH Power control 00H- 

03H 

0FH Automatatic recalibration 00H- 

96H 

10H Data Format 00H- 

1FH 

11H – 

1FH 



05H Serial number 32bit 00H, 12H, 34H, 56H, 78H 5 

00H RSSI current 01H, 90H 2 

01H RSSI peak 01H, A3H 2 

02H Temperature 01H, 18H 2 

09H Receive-frequency 02H, 01H 2 

0AH Transmittion frequency 02H, 01H 2 

0BH RF data rate 02H, 04H 2 

0CH RS232-baud rate 02H, 04H 2 

0DH Power up mode 02H, 20H 2 

0EH Power control 02H, 03H 2 

0FH Automatatic recalibration 02H, 3CH 2 

10H Data Format 02H, 03H 2 

EEPROM register read on 

this address. 

Frequency channel TX 

and RX 

Frequency channel only 

RX 

Frequency channel only 

TX 

03H, 55H 2 

08H, 01H 2 

09H, 01H 2 

0AH, 01H 2 

RF data rate 0BH, 04H 2 

RS232 baud rate 0CH, 04H 2 

Configuration for power 

up, sleep and wakeup 

0DH, 20H 2 

Turn LED and HF on/off 0EH, 03H 2 

Temperature- and time 

controlled calibration 

Data format and radio 

telegram format 

0FH, 3CH 2 

10H, 03H 

2


functional 

group 

WRITE 

Possible 

only in 

RAM, not 

in 

Byte2 

Bit0... 

6 

Command or function Byte3 Description Answer (example) Number 

of bytes 

20H Sleep 00H- 

21H 

21H Calibrate now 00H Start VCO-calibration 

calibration successful 

calibration unsuccessful 

22H- 

2CH 



2DH EEPROM WR-enable 00H- 

FFH 

2EH EEPROM Data 00H- 

FFH 

EEPROM 2FH EEPROM address 00H- 

FFH 

REPORT 

Automatic 

output of 

values 

ERROR 

READY. Ready sign of 

the transceiver after 

power up, MCLR\ - 

Reset or wakeup 

Answers to invalid 

functions or function 

value 

Example of initialization in C 

Defines sleep and wakeup 20H, 21H 2 

Enable specific address 

for writing 

Write this Data byte to 

EEPROM 

EEPROM address which 

will be written on 

Calibration value OK, 

after power up or MCLR\ - 

Reset 

21H. 00H 

21H, 01H (typ. 50ms) 

21H, 02H (typ. 250ms) 

2 

2 

2 

2DH, 10H 2 

2E, 43H 2 

2EH, 10H 2 

30H, 00H 2 

Calibration value failure, 

after power up or MCLR\ - 

Reset 

30H, 80H 2 

Ready after wakeup 30H, 01H 2 

Invalid function 

(Byte2) 

Invalid function 

value(Byte3) 

38H, 00H 2 

38H, 01H 2 

The following example shows the usage of the instruction set in the programming language C. The shown 

initialization sequence configures the transceiver in the desired operation mode. The configuration is saved 

in the EEPROM of the transceiver because the Bit7 of the command = 1. After the next power up, this 

configuration will be available right away and without a configuration. 

While writing in EEPROM you have to be careful that the limited number of 100’000 writing cycles per 

parameter aren’t exceeded. When you try to write a value in the EEPROM which is already there then the 

write instruction will not be done. So you can write a constant configuration in the EEPROM at will. The data 

is thereby just written in the EEPROM the very first time. When the configuration is changed often then you 

should write it exclusively in the RAM so that the maximum number of write cycles of the EEPROM aren’t 

exceeded. For that, delete in the following code in each case Bit7 of the command byte. 

The VCO-calibration will be done again in the end of the initialization so that you can check the result of the 

calibration. The VCO-calibration is made automatically with every power up but even with five calibration 

failures, it wouldn’t result in a error report.


int error_code; // Globale Variable für Fehler-Code 

// ------------------------------------------------------------------------------------------------ 

// Initialisierung eines TRX433-10-C2 direkt ins EEPROM (beschränkte Speicherzyklen beachten). 

// Für Initialisierung nur ins RAM Bit7 des Befehlsbytes auf null setzen. 

// Die Speisung des Transceivermoduls wird kurz vor oder zu Beginn der Initialisierung eingeschaltet. 

// 

// input: - 

// output: error_code: 0 = Komplette Initialisierung erfolgreich 

// 1 = Kein Ready-Report empfangen oder Kalibrationskonstanten fehlerhaft 

// 2 = Fehler in RS232 Kommunikation 

// 3 = Fehler bei VCO-Kalibration 

int init_trx() 

{ 

error_code = 0; // Init Fehler-Code auf erfolgreich 

// hier wird die Speisung des Transceivers eingeschaltet 

// danach muss sich das Modul mit dem REPORT READY melden 

if(!echo(0x30, 0x00)){ // Ready-Report empfangen (Ready-Report wird 170-180ms nach 

// Powerup des Transceivermoduls gesendet). Die Funktion echo() liest zwei 

// Bytes über RS232 ein und prüft, ob diese mit den gewünschten zwei Bytes 

// übereinstimmen. Sie beinhaltet eine Timeoutfunktion, damit bei 

// ausbleibender Antwort vom Modul die Funktion nicht hängen bleibt. 

error_code = 1; // Falls kein Ready-Report empfangen wurde oder Kalibrations- 

return error_code; // konstanten fehlerhaft => Fehler_Code zurückgeben 

} // und Initialisierung abbrechen 

else{ // Ready-Report empfangen. Modul bereit für Initialisierung 

output_rs232(0x88, 0x46); // Frequenz RX+TX : 433.925MHz 

output_rs232(0x8B, 0x02); // Funkdatenrate : 4.8kbit 

output_rs232(0x8C, 0x04); // RS232 Baudrate : 19.2kbaud 

output_rs232(0x8D, 0x25); // Powerup mode : -Continue nach Wakeup 

// -Run nach Powerup 

// -Alle Pins bleiben unverändert 

output_rs232(0x8E, 0x03); // Power control : LED on, HF on 

output_rs232(0x8F, 0x01); // automat. Rekalibration control: -automatisch bei dT>20°C 

output_rs232(0x90, 0x03); // Data Format: : -CRC16 ein 

: -Handshake ein 

: -Fastsend aus 

: -RSSI-TLG nicht anhängen 

: -RSSI-RUHE nicht anhängen 

if(error_code){ // War Kommunikation immer erfolgreich? 

return error_code; // Nein. => Fehler_Code zurückgeben und Initialisierung abbrechen 

} 

// **** Initialisierung war bis hierher erfolgreich ***** 

output_rs232(0x21, 0x00); // VCO-Kalibration starten 

if(!echo(0x21, 0x01)){ // Antwort von Kalibration abwarten (typ. 50ms, maximal 250ms) 

error_code = 3; // Fehler! Fehler-Code setzen 

} 

return error_code; // Fehler-Code zurückgeben 

} // error_code == 0 bedeutet Initialisierung erfolgreich 

} 

// ------------------------------------------------------------------------------------------------ 

// Gibt einen Befehl gemäss Befehlsliste aus (3 Bytes: Startzeichen == 0xB0, Funktion, Wert). 

// Die Antwort wird geprüft. Falls das Transceivermodul keine oder eine falsche Antwort zurückgibt, 

// so wird der Befehl maximal 3x wiederholt. 

// Danach wird im Fehlerfall der Fehler-Code "Fehler in RS232 Kommunikation" gesetzt. 

// input: funktion = Funktion gemäss Befehlssatz 

// wert = Wert gemäss Befehlssatz 

// output: - 

void output_rs232(int funktion, int wert) 

{ 

int i = 3; // maximal 3 Wiederholungen 

while(i){ // Solange noch nicht 3 Versuche gemacht... 

putchar(0xB0); // Startzeichen über RS232 ausgeben (0xB0) 

putchar(funktion); // Funktion über RS232 ausgeben 

putchar(wert); // Wert über RS232 ausgeben 

if(echo((funktion&0x7F), wert)){ // Stimmt Antwort (EEprom-Bit der Funktion nicht prüfen)? 

i = 0; // Ja. Kommunikation erfolgreich -> While-Schlaufe beenden 

} 

else{ // Nein, falsche oder keine Antwort 

if(!--i){ // Befehl schon dreimal wiederholt? 

error_code = 2; // Ja, Fehler-Code setzen 

} } } } 

// ------------------------------------------------------------------------------------------------


Detailed description of the functions 

Functional group READ 

Note: the current configuration in the RAM can differ from the configuration of the EEPROM when a 

configuration with the WRITE-command just was saved in the RAM. Read are always the configurations from 

EEPROM. 

_____________________________________________________________________________________ 

Functional name READ Software version Function 00H 

Functional call 0B0H, 00H, 00H 

Answer 00H, VERS, WEEK, YEAR 

Current software version in the Flash-memory of the transceiver. See READ Software type 

_____________________________________________________________________________________ 

Functional name READ Software type Function 00H 


Answer 00H, 03H 

Software type 1 is called „A“, software type 2 is called „B“, and software type 3 is called „C“. These names 

are part of the module designation. The letter „C” marks the software type in TRX433-10C2. 

Type A = radio modem, Type B = Direct mode, Typ C = byte mode. 

Only the software type along with the software version identify the firmware of the transceiver clearly. 

See READ software version and coding marking of the transceiver module. 

_____________________________________________________________________________________ 

Functional name READ instruction set version Function 00H 


Answer 00H, 02H 

Instruction set version of the transceiver. This is part of the module designation. 

The last number of TRX433-10C2 identifies the instruction set version 2. 

The functions of the transceiver can be extended or adjusted on customer demand in the future. If required 

the backwards compatibility with former versions can be ensured with this version. See coding marking of the 

transceiver module. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ hardware version Function 00H 


Answer 00H, HVERS 

This is part of the module designation and is comprised of assembly variants and module type. 

The number 10 in TRX433-10C2 marks the hardware version 10. 

The transceiver is produced in multiple assembly variants. 

HVERS = 0AH: 16MHz µP clock frequency, internal voltage regulator 3.3V, loop filter 19.2kbaud 

HVERS = 0BH: 8MHz µP clock frequency, internal voltage regulator 3.0V, loop filter 19.2kbaud 

HVERS = 0CH: 16MHz µP clock frequency, without internal voltage regulator, loop filter 19.2kbaud 

HVERS = 0DH: 8MHz µP clock frequency, without internal voltage regulator, loop filter 19.2kbaud 

HVERS = 0EH: 8MHz µP clock frequency, internal voltage regulator 3.3V, loop filter 19.2kbaud 

There might accrue other hardware versions in future. See coding marking of the transceiver module. 

________________________________________________________________________________ 

Functional name READ Frequency version Function 00H 


Answer 00H, FVERS 

Frequency - version of the transceiver. This is part of the module designation. 

The Numbers 433 marks the frequency version in TRX433-10C2. 

FVERS = 0: 433 MHz band, 433.0625 - 434.7875MHz 



See coding marking of the transceiver module. 

_____________________________________________________________________________________ 

Functional name READ serial number Function 00H 


Answer 00H, SER0, SER1, SER2, SER3 

32bit unique serial number of the transceiver. 

SER0 = LSB, SER3 = MSB of the 32 bit-serial number 

See coding marking of the transceiver module. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ RSSI current Function 01H 


Answer 01H, RSSI 

RSSI in two’s complement, range -128 dBm … -60 dBm, resolution 1dBm 

Current RSSI value (Received Signal Strength Indicator) in dBm. 

The RSSI-value is established every 3ms independent of the functional call. RSSI shows therefore the field 

strength of a time that is max. 3ms back. RSSI = -128dBm while sending. 

The max. measurable value is -60dBm. The lower noise-floor depends mainly on the adjusted RF data rate. 

See paragraph RSSI and function READ RSSI peak. 

_____________________________________________________________________________________ 

Functional name READ RSSI peak Function 01H 


Answer 01H, RSSI_peak 

RSSI_peak in two’s complement, range-128 dBm … -60 dBm, resolution 1dBm 

Maximum (peak hold) of the RSSI since last call. (Received Signal Strength Indicator) in dBm. 

The RSSI_peak is initialized after every call of this function and right after sleep. RSSI = -128 while sending. 

The max. measurable value is -60dBm. The lower noise-floor depends mainly on the adjusted RF data rate. 

See paragraph RSSI and function READ RSSI current. 

_____________________________________________________________________________________ 

Functional name READ temperature Function 01H 


Answer 01H, TEMP 

TEMP in two’s complement, range -40°C … +115°C, resolution 1°C 

Temperature transceiver module in °C. 

The temperature is only actualized every 5 seconds no matter how often you invoke this function. 

The temperature is not actualized until the microcontroller was active for 5 seconds because all the timers 

are stopped during the sleep. The RF-part of the transceiver doesn’t have to be active to measure the 

temperature. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ Receive frequency (from EEPROM) Function 02H 


Answer 02H, FREQ 

FREQ = channel number according to frequency table 

Range 1…139 for 433 MHz band 


Frequency channel for the radio reception according to frequency table. 

The channel spacing is fix 12.5kHz independent on the adjusted RF data rate. 

Note: the current configuration (RAM) can differ from the configuration in EEPROM! 

_____________________________________________________________________________________ 

Functional name READ transmittion frequency (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0AH 



Range 1…139 for 433 MHz Band 

Range 1…159 for 868 MHz Band 

Frequency channel for the transceiver according to the frequency table. 

The channel spacing is fix 12.5 kHz independent on the adjusted RF data rate. 


_____________________________________________________________________________________ 

Functional name READ RF data rate (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0BH 

Answer 02H, RF_bitrate 

RF_bitrate = 00H: 1.2 kbit/s; Manchester, GFSK, 9.6kHz RF-bandwidth 

RF_bitrate = 01H: 2.4 kbit/s; NRZ, GFSK, 9.6kHz RF-bandwidth 



RF_bitrate = 04H: 19.2kbit/s; NRZ, GFSK, 51.2kHz RF-bandwidth 


RF data rate for transmittion and receiver 

The data coding type, the modulation type and the RF-bandwidth are linked closely with the RF data rate. 

RF data rates >19.2kbits/s are possible but they require a clock frequency of 16MHz µP and an accordant 

dimensioned loop filter respectively an assembly modification. The reception sensitivity by small RF data 

rates is reduced thereby. The standard version TRXnnn-10C2 is assembled with a loop filter for max 

19.2kbits/s. 


_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ RS232 baud rate (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0CH 

Answer 02H, BAUD 

BAUD = 00H: 1.2 kBaud, tolerance +- 1% 






BAUD = 06H: 57.6 kBaud, tolerance +- 1% with 16 MHz clock 

57.6 kBaud, tolerance -3.5% +-1% with 8 MHz clock 

BAUD = 07H: 115.2kBaud, tolerance -3.5% +-1% 

The highest baud rate of 115.2kBaud is just possible with a 16MHz µP clock frequency. 

The baud rates have the stated typ. tolerance of the ideal value. The at a time highest adjustable baud rate 

is 3.5% lower than the nominal value, i.e. 111.1kBaud respectively 55.5kBaud (by 8MHz µP clock 

frequency). 

The sum of the tolerance of both communication partners should be smaller than 6% (standard) to avoid 

communication problems. 

Notes configuration-baud rate 

The adjusted RS232 baud rate just applies for the normal data traffic but not during the configuration 

(MODE-Pin on high). An automatic detection of baud rate is implemented in the configuration mode, which 

detects automaticly all of the baud rates above (there is a 16MHz µP clock frequency required for 

115.2kBaud). That means it can be configured with any baud rates. Automatic output like the READY after a 

power up are just output when the module is in the configuration mode (MODE-Pin on high). The automatic 

outputs are output in the baud rate which was the last one used to configure. These automatic outputs are 

suppressed in a normal operating mode (MODE-Pin on low). 


_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ power up mode (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0DH 

Answer 02H, PWUP_mode (Bit register) 

The individual bits of the PWUP_mode define the behavior of the transceiver after a power up. The 

command is e.g. important for a battery operation or by switched supply so that the transceiver doesn’t use 

battery current after a change of battery and doesn’t have to be configured by an external controller. 

The configuration of PWUP_mode just effects when bit2 = 0. Otherwise the transceiver starts normally by a 

power up. Therefore, bit2 is the “main switch”. 

This command is alike the sleep-command. The difference is that it only effects by Power up as well as by 

an automatic sleep right after a power up. 

Bit0 and bit1 just effect for a wakeup out of an automatic sleep after a power up (therefore not by a normal 

wakeup after a sleep-command). By a continue after a wakeup, the transceiver is ready again pretty fast (by 

19.2kbit/s RF data rate after 3ms, by 2.4kbits/s RF data rate after 5ms) after a wakeup and doesn’t make a 

calibration and configuration, compared to the soft-reset, which normally takes about 75ms. 

PWUP_mode, bit0 = 0: Wakeup makes an internal soft-reset, i.e. the program will be restarted 

PWUP_mode, bit0 = 1: Continue after wakeup, i.e. program continues where it was before the sleep 

PWUP_mode, bit1: unused, reserved for wakeup 

PWUP_mode, bit2 = 0: automatic sleep after power up. Transceiver has to be awakened afterwards. 

PWUP_mode, bit2 = 1: Runs after power up i.e. transceiver starts after power up with config. from EEPROM 

PWUP_mode, bit3: unused, reserved for power up 

PWUP_mode, bit4: unused, reserved for sleep-state 

PWUP_mode, bit5 = 0: set all pins except WKUP-pin during sleep on output with low-level 

PWUP_mode, bit5 = 1: all pins unchanged 

The automatic sleep after the power up can be stopped with the WKUP-Pin. For that a change in level has to 

appear at the WKUP-Pin. The transceiver reports after the wake up with the READY-signal 30H, 01H “ready 

after wake up” and the pins CTS and RxD become input if they were set on output during the sleep (the 

READY-signal will only be output if the transceiver is in the configuration mode). Alternatively, the RTS-pin 

can be supervised. After a power up with an automatic sleep the RTS-Pin changes to high after ca. 110ms 

(sleep will be started). When the transceiver is awakened (with slope change on WKUP-pin) then the RTSpin 

will be reset to low. You can also use a negative slope on the RTS-pin as a ready signal. 

Note: only the configuration in the EEPROM is of interest, the value in the RAM will be lost by a power down 

– power up cycle! 

See paragraph energy saving mode and WRITE sleep. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ power control (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0EH 

Answer 02H, PWR_ctrl (Bit register) 

PWR_ctrl, bit0 = 0: LED transceiver = OFF 

PWR_ctrl, bit0 = 1 LED transceiver = ON 

PWR_ctrl, bit1 = 0: RF-part transceiver = OFF 

PWR_ctrl, bit1 = 1: RF-part transceiver = ON 

The individual bits of PWR_ctrl enable and disable blocks of the transceiver to save current. The calibration 

data persists when the transceiver is disabled and enabled with this command. 

This command can be used for e.g. reading the temperature or switch the LED, for which you don’t need a 

radio module. The used current is only a fraction amount of the normal usage by a disabled radio part. 


_____________________________________________________________________________________ 

Functional name READ automatic recalibration control (from EEPROM) Function 02H 

Functional call 0B0H, 02H, 0FH 

Answer 02H, ACAL 

ACAL = 0: no automatic VCO-calibration 

ACAL = 1: recalibrates automatically by ∆T = 20°C 

ACAL = mm: recalibrates automatically every mm minutes 

mm = 5d … 150d (Interval 5…150 minutes) 

Time- or temperature controlled automatic VCO-calibration. 

The VCO has to be recalibrated when: 

• the supply voltage changes more than 0.25V. Be careful with this on versions without an internal 

voltage regulator by battery operation. 

• the temperature changes more than 40°C 

There is no radio contact possible during the calibration and the current consumption is the same as during 

the reception mode. Normally, the calibration takes about 50ms i.e. it’s straightaway finished successfully. If 

the first try wasn’t successful then the transceiver will try to recalibrate up to five times. Therefore the 

calibration can take up to 250ms. Beginning, ending and state of the automatic recalibration will not be 

reported, not even when the module is in the configuration mode (contrary to the function “calibrate now” 

(21H, 00H) in which the state of the calibration is reported when the transceiver is in the configuration mode). 

The time controlled outputs only result work as expected when the sleep-command isn’t used because all 

the timers are stopped during the sleep. The same with the temperature controlled calibration because the 

new temperature is only read every 5 seconds. 


_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ Data Format (from EEPROM) Function 02H 


Answer 02H, FORMAT (Bit register) 

The individual bits of the FORMAT define the different possible settings in connection with the serial data 

transmission over RS232 and the radio data transmission. To see the exact effects on the timing behavior 

and the individual settings go to the paragraph radio transmission. 

FORMAT, bit0 = 0: CRC16 off. No checksum of the radio data. 

FORMAT, bit0 = 1: CRC16 on. Checksum of the radio data with CRC16 

FORMAT, bit1 = 0: Handshake off. No Handshake of the RS232-interface 

FORMAT, bit1 = 1: Handshake on. Handshake of the RS232-interface with RTS/CTS 

FORMAT, bit2 = 0: Fast send off. Start of the radio transmittion after 2-3-byte-pause over RS232 

FORMAT, bit2 = 1: Fast send on. Start of the radio transmittion right after the first byte over RS232 

FORMAT, bit3 = 0: After data out, the RSSI of the radio telegram is not output 

FORMAT, bit3 = 1: After data out, the RSSI of the radio telegram will be output 

FORMAT, bit4 = 0: After the RSSI of the radio telegram, the no signal condition– RSSI will not be output 

FORMAT, bit4 = 1: After the RSSI of the radio telegram, the no signal condition– RSSI will be output 

The CRC16 – checksum is a 16-bit checksum which helps to protect the radio transmittion. If the checksum 

calculated by the receiver isn’t the same as the checksum transmitted from the radio module then the data 

will be rejected. 

When the Handshake is enabled then you shouldn’t send any data over the RS232 to the transceiver module 

as long as the RTS-pin is set to high. The user can stop the output of data through the transceiver with 

setting the CTS-pin on high. 

When the handshake is disabled then the user himself is responsible that the internal transmittion buffer and 

receive buffer of the transceiver module won’t overfill. RTS- and CTS-line are ignored in this case. 

Fast send can just be used up to a RF data rate of 19.2kbit/s (respectively 9.6kbits/s by 8MHz µP clock 

frequency) because an enabled fast send means more computing effort for the transceiver. 

The no signal condition – RSSI can just be output when the RSSI of the radio telegram is output as well. The 

RSSI of the telegram and the no signal condition – RSSI are output in a two’s complement in dBm in addition 

to the over radio transmitted payload. 

Note: 

• The current configuration (RAM) can differ from the configuration in EEPROM! 

• When the CTS-pin is used as a handshake then you shouldn’t send any further data to the transceiver 

module as long as the CTS-pin is set on high because those data would be interpreted from the 

transceiver module as configurations data 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name READ EEPROM Function 03H 

Functional call 0B0H, 03H, EE_ADR 

Answer 03H, EE_REG 

EE_REG: EEPROM register contents to the address EE_ADR 

EE_ADR = 0 … FFH 

Read any EEPROM register byte. 

The part of the EEPROM that the transceiver doesn’t use (address 0D0H…0FEH) can be used free from the 

application. The calibration values of the transceiver, diverse constants like the configuration are stated in 

this EEPROM as well and are accessible to the application. 

The writing protection EE_WRPROT for the EEPROM is in the EEPROM-address FFH. 

Every one of the 8 bits of the EEWRPROT controls an EEPROM part as follows: 

Bitn = 0: Address range is writable and readable (factory setting) 

Bitn = 1: Address range is not writable and only readable 

EE_WRPROT, Bit0 address 00H...1FH calibration values frequency and RSSI 

EE_WRPROT, Bit1 address 20H...6FH calibration values temperature compensation 

EE_WRPROT, Bit2 address 70H...8FH calibration values reserve 

EE_WRPROT, Bit3 address 90H...9FH Hardware constant 

EE_WRPROT, Bit4 address A0H...AFH Software constant 

EE_WRPROT, Bit5 address B0H...CFH current transceiver configurations 

EE_WRPROT, Bit6 address D0H...FEH free usable for applications 

EE_WRPROT, Bit7 address FFH...FFH EE_WRPROT (this byte) 

The write protection EE_WRPROT only applies for the access with the commands WRITE EEPROM and not 

for the other WRITE commands which also write in the EEPROM. 

Note: 

• Even if the whole EEPROM is free to write in, only the to the application assigned block can be used 

(address 0D0H…0FEH) 

• When the application uses the EEPROM as memory then set EE_WRPROT on b’10111111’ = BFH to 

protect the EEPROM from unwanted changes. 

• After bit7 of EE_WRPROT in EEPROM is set on 1 then the writing protection as a whole can’t be 

changed anymore. Therefore this command has to be used deliberately! 

• When other EEPROM-data e.g. the calibration values were changed then the transceiver might be 

unusable and has to be recalibrated from the producer. 

See EEPROM function 2DH, 2EH, 2FH for writing on any EEPROM registers. 

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Function group WRITE 

When the parameter are saved in RAM and in EEPROM then you have to be careful that the limited number 

of 100’000 EEPROM write cycles per parameter aren’t exceeded. But when you try to write a value into the 

EEPROM which is already there then the write instruction will not be done. Therefore you can write a 

configuration that doesn’t change in the EEPROM anytime. The data is thereby just written in the EEPROM 

the very first time. 

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Functional name WRITE frequency RX+TX Function 08H 

Functional call 0B0H, 08H, FREQ 





Frequency channel for the radio reception and transmitting according to frequency table. Transmititon- and 

reception channel are set to the same frequency together. 

The channel spacing is fix 12.5kHz, independent of the adjusted RF data rate. 

When Bit7 of Byte2 is high then the parameter is stored in the EEPROM as well and the configuration is 

activated immediately after a power up. The answer is always with Bit7 = 0. 

The frequency change needs 2ms by 19.2kbit/s RF data rate, 5ms by 2.4kbit/s RF data rate, i.e. after that 

time the new frequency is set and can be used. 

_____________________________________________________________________________________ 

Functional name WRITE frequency RX Function 09H 

Functional call 0B0H, 09H, FREQ 





Frequency channel for the radio Transmission and reception channels may differ! 






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Functional name WRITE frequency TX Function 0AH 

Functional call 0B0H, 0AH, FREQ 

Answer 0AH, FREQ 




Frequency channel for the transmittion according to frequency table. Transmission and reception cahnnels 

may differ. 






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Functional name WRITE RF data rate Function 0BH 

Functional call 0B0H, 0BH, RF_bitrate 

Answer 0BH, RF_bitrate 

RF_bitrate = 00H: 1.2 kbit/s; Manchester, GFSK, 9.6kHz RF-bandwidth 






RF data rate for the transmittion and the receiver. 

With the RF data rate, the data coding type, the module type, and the RF-bandwidth are attached. 

RF data rates >19.2kbits/s are possible but they require a clock frequency of 16MHz µP and an accordingly 

dimensioned loop filter respectively an assembly modification. Thereby the receiver sensitivity by small RF 

data rates is reduced. The standard version TRXnnn-10C2 is assembled with a loop filter for max. 

19.2kbits/s. 

When Bit7 of Byte2 is high then the parameter is stored in EEPROM as well and the configuration is 

activated right after the start up. The answer is always Bit7 = 0. 

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Functional name WRITE RS232 baud rate Function 0CH 

Functional call 0B0H, 0CH, BAUD 

Answer 0CH, BAUD 

BAUD = 00H: 1.2 kBaud, tolerance+- 1% 

BAUD = 01H: 2.4 kBaud, tolerance+- 1% 





BAUD = 06H: 57.6 kBaud, tolerance +- 1% with 16 MHz clock 

57.6 kBaud, tolerance -3.5% +-1% with 8 MHz clock 

BAUD = 07H: 115.2 kBaud, tolerance -3.5% +-1% 

The highest baud rate of 115.2kbaud is just possible with a 16MHz µP clock frequency. 

The baud rates have the stated typ. tolerance of the ideal value. The at a time highest adjustable baud rate 

is 3.5% lower than the nominal value, i.e. 111.1kBaud respectively 55.5kBaud (by 8MHz µP clock 

frequency). 

The sum of the tolerance of both communication partners should be smaller than 6% (standard) to avoid 

communication problems. 

Note configuration-baud rate 

The adjusted RS232 baud rate just applies for the normal data traffic but not during the configuration 

(MODE-Pin on high). An automatic detection of baud rate is implemented in the configuration mode which 

automaticly detects all of the baud rates above (there is a 16MHz µP clock frequency required for 

115.2kBaud). That means it can be configured with any baud rate. Automatic output like the READY after a 

power up are just output when the module is in the configuration mode (MODE-Pin on high). The automatic 

outputs are output in the baud rate which was the last one used to configure. These automatic outputs are 

suppressed in a normal operating mode (MODE-Pin on low). 



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Functional name WRITE power up mode Function 0DH 

Functional call 0B0H, 0DH, PWUP_mode 

Answer 0DH, PWUP_mode (Bit register) 

The individual bits of the PWUP_mode define the behavior of the transceiver after a power up. The 

command is e.g. important for a battery operation or with switched supply so that the transceiver doesn’t use 

battery current after a change of battery and doesn’t have to be configured by an external controller. 

The configuration of PWUP_mode just effects when bit2 = 0. Otherwise the transceiver starts normally by a 

power up. Therefore, bit2 is the “main switch”. 

This command is alike the sleep-command. The difference is that it only effects by Power up as well as by 

an automatic sleep right after a power up. 

Bit0 and bit1 just effect for a wakeup out of an automatic sleep after a power up (therefore not by a normal 

wakeup after a sleep-command). By a continue after a wakeup, the transceiver is ready again pretty fast (by 

19.2kbit/s RF data rate after 3ms, by 2.4kbits/s RF data rate after 5ms) after a wakeup and doesn’t make a 

calibration and configuration, compared to the soft-reset, which normally takes about 75ms. 

PWUP_mode, bit0 = 0: Wakeup makes an internal soft-reset, i.e. the program will be restarted 

PWUP_mode, bit0 = 1: Continue after wakeup, i.e. program continues where it was before the sleep 

PWUP_mode, bit1: unused, reserved for wakeup 

PWUP_mode, bit2 = 0: automatic sleep after power up. Transceiver has to be awakened afterwards. 

PWUP_mode, bit2 = 1: Runs after power up i.e. transceiver starts after power up with config. from EEPROM 

PWUP_mode, bit3: unused, reserved for power up 

PWUP_mode, bit4: unused, reserved for sleep-state 

PWUP_mode, bit5 = 0: set all pins except WKUP-pin during sleep on output with low-level 

PWUP_mode, bit5 = 1: all pins stay unchanged 

The automatic sleep after the power up can be stopped with the WKUP-Pin. For that a change in level has to 

appear at the WKUP-Pin. The transceiver respnds after the wake up with the READY-signal 30H, 01H “ready 

after wake up” and the pins CTS and RxD become inputs if they were set on output during the sleep (the 

READY-signal will only be output if the transceiver is in the configuration mode). Alternatively, the RTS-pin 

can be supervised. After a power up with an automatic sleep the RTS-Pin changes to high after ca. 110ms 

(sleep will be started). When the transceiver is awakened (with slope change on the WKUP-pin) then the 

RTS-pin will be reset to low. You can also use a negative slope on the RTS-pin as ready signal. 

Note: only the configuration in the EEPROM is of interest, the value in the RAM will be lost by a power down 

– power up cycle! Therefore Bit7 of Byte2 has to be high and the parameter has to be stored in EEPROM so 

that the configuration will be activated after a power up. The answer is always with Bit7 = 0. 

See paragraph energy saving mode and WRITE sleep. 

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Functional name WRITE power control Function 0EH 

Functional call 0B0H, 0EH, PWR_ctrl 

Answer 0EH, PWR_ctrl (Bit register) 

PWR_ctrl, bit0 = 0: LED transceiver = OFF 

PWR_ctrl, bit0 = 1 LED transceiver = ON 

PWR_ctrl, bit1 = 0: RF-part transceiver = OFF 

PWR_ctrl, bit1 = 1: RF-part transceiver = ON 

The individual bits of PWR_ctrl enable and disable blocks of the transceiver to save current. The calibration 

data persist when the transceiver is disabled and enabled with this command. 

The RF-part needs 2ms by 19.2kbit/s RF data rate, 5ms by 2.4kbit/s RF data rate to get ready to use after 

that command. 

This command can be used for e.g. reading the temperature or switch the LED for which you don’t need a 

radio module. The used current is only a fraction amount of the normal usage by a disabled radio part. 


activated right after the start up. The answer is always with Bit7 = 0. 

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Functional name WRITE automat. recalibration control Function 0FH 

Functional call 0B0H, 0FH, ACAL 

Answer 0FH, ACAL 

ACAL = 0: no automatic VCO-calibration 

ACAL = 1: recalibrates automatically by ∆T = 20°C 

ACAL = mm: recalibrates automatically every mm minutes 

mm = 5d … 150d (Interval 5…150 minutes) 

Defines the time- or temperature controlled automatic VCO-calibration. 

The VCO has to be recalibrated when: 

• the supply voltage changes more than 0.25V. Be careful with this on versions without an internal 

voltage regulator by battery operation. 

• the temperature changes more than 40°C 

There is no radio contact possible during the calibration and the current consumption is the same as during 

the reception mode. Normally, the calibration takes about 50ms i.e. it’s straightaway finished successfully. If 

the first try wasn’t successful then the transceiver will try to recalibrate up to five times. Therefore the 

calibration can take up to 250ms. Beginning, ending and state of the automatic recalibration will not be 

reported, not even when the module is in the configuration mode (contrary to the function “calibrate now” 

(21H, 00H) in which the state of the calibration is reported when the transceiver is in the configuration mode). 

The time controlled outputs only work as expected when the sleep-command isn’t used because all the 

timers are stopped during the sleep. The same with the temperature controlled calibration because the new 

temperature is only read every 5 seconds. 



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_____________________________________________________________________________________ 

Functional name WRITE Data Format Function 10H 

Functional call 0B0H, 10H, FORMAT 

Answer 10H, FORMAT (Bit register) 

The individual bits of the FORMAT define the different possible settings in connection with the serial data 

transmission over RS232 and the radio data transmission. To see the exact effects on the timing behavior 

and the individual settings go to the paragraph radio transmittion. 

FORMAT, bit0 = 0: CRC16 off. No checksum of the RF data. 

FORMAT, bit0 = 1: CRC16 on. Checksum of the RF data with CRC16 

FORMAT, bit1 = 0: Handshake off. No handshake of the RS232-interface 

FORMAT, bit1 = 1: Handshake on. Handshake of the RS232-interface with RTS/CTS 

FORMAT, bit2 = 0: Fast send off. Start of the radio transmittion after 2-3-byte-pause over RS232 

FORMAT, bit2 = 1: Fast send on. Start of the radio transmittion right after the first byte over RS232 

FORMAT, bit3 = 0: After data out, the RSSI of the radio telegram is not output 

FORMAT, bit3 = 1: After data out, the RSSI of the radio telegram will be output 

FORMAT, bit4 = 0: After the RSSI of the radio telegram, the no signal condition– RSSI will not be output 

FORMAT, bit4 = 1: After the RSSI of the radio telegram, the no signal condition– RSSI will be output 

The CRC16 – checksum is a 16-bit checksum which helps to protect the radio transmittion. If the checksum 

calculated by the receiver isn’t the same as the checksum transmitted from the radio module then the data 

will be rejected. 

When the Handshake is enabled then you shouldn’t send any data over the RS232 to the transceiver module 

as long as the RTS-pin is set to high. The user can stop the output of data through the transceiver by setting 

the CTS-pin on high. 

When the handshake is turned of then the user is responsible for himself that the internal transmittion - and 

receiving buffer of the transceiver module won’t overfill. RTS- and CTS-line are ignored in this case. 

Fast send can just be used up to a RF data rate of 19.2kbit/s (respectively 9.6kbits/s by 8MHz µP clock 

frequency) because an enabled fast send means more computating effort for the transceiver. 

The no signal condition – RSSI can just be output when the RSSI of the radio telegram is output as well. The 

RSSI of the telegram and the no signal condition – RSSI are output in two’s compliment in dBm in addition to 

the over radio transmitted payloads. 


activated right after the start up. The answer is always with Bit7 = 0. 

Note: When the CTS-pin is used as handshake then no further data should be sent as long as the CTS-pin 

is set on high, otherwise these data would be interpreted from the transceiver module as configurations data. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name WRITE sleep Function 20H 

Functional call 0B0H, 20H, WKUP_mode 

Answer 20H, WKUP_mode (Bit register) 

Sets the whole transceiver in the sleep-mode to save energy. Transceiver and LED will be disabled and the 

clock of the micro controller will be stopped. 

The WKUP-Pin has to be on its sleep-level (high or low) before the sleep command but the latest 50µs after 

the answer to the sleep command. Afterwards a level change starts immediately a wake up. 

The individual bits of the PWUP_mode define the behavior of the transceiver during the sleep as well as 

after the wake up. These configurations are important for the battery operation. 

WKUP_mode, bit0 = 0: Wake up starts a soft-reset, i.e. program will restart. 

WKUP_mode, bit0 = 1: Continue after Wakeup, i.e. program resumes where it was before the sleep. 

WKUP_mode, bit1: unused, reserved for wake up 

WKUP_mode, bit2: unused 

WKUP_mode, bit3: unused 

WKUP_mode, bit4: unused, reserved for sleep-state 

WKUP_mode, bit5 = 0: sets all Pins except WKUP-pin during the sleep on output with Low-level. 

WKUP_mode, bit5 = 1: all Pins stay unchanged 

Sleep can be stopped with the WKUP-Pin. For that a change in level has to appear at the WKUP-Pin. The 

transceiver answers after the wake up with the READY-signal 30H, 01H (the READY-signal will only be 

output if the transceiver is in the configuration mode).The pins CTS and RxD become inputs again if they 

were set on output during the sleep. 

The pin can be supervised alternatively to the READY-report 30H, 01H-pin. The RTS-pin changes to high 

after the sleep-command. When the transceiver is ready again after a wake up then the RTS-pin is set on 

low again. Therefore you can also use a negative slope on the RTS-Pin as a ready signal. 

The last calibration data are still active after a wake up. If they are not valid anymore after the wake up (e.g. 

because of great temperature change) then you have to recalibrate. By soft-reset, it calibrates and sets the 

configuration of the EEPROM automatically. That’s why the transceiver takes about 75ms to get ready after 

the soft-reset, compared to the Continue after a wake up which doesn’t calibrate automatically and is 

therefore ready after 3ms (by 19.2kbit/s RF data rate) respectively 5ms (by 2.4 kbit/s RF data rate). 

All timers are stopped for automatic outputs etc. during the sleep and won’t continue running until a wake up. 

Time controlled outputs therefore just result as expected when the sleep command isn’t used. 

See function WRITE power up mode as well as the paragraph save current consumption. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name WRITE calibrate now Function 21H 


Answer 21H, 00H immediately when calibration starts 

21H, 01H after typ. 50ms, when calibration ends successfully 

resp. 21H, 00H immediately when calibration starts. 

21H, 02H after typ. 250ms, if calibration was not successful 

Starts immediately a VCO-calibration. If the transceiver module is in the configuration mode then the start 

and the ending will be reported just as the result of the calibration. Normally, the calibration takes about 

50ms i.e. it’s straightaway finished successfully. If the first try wasn’t successful then the transceiver tries to 

recalibrate up to five times. Therefore the calibration can take from 50ms up to 250ms. 

When a calibration was not successful then the call can be repeated. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name WRITE EEPROM WR-enable Function 2DH 

Functional call 0B0H, 2DH, ADR 

Answer 2DH, ADR 

ADR EEPROM address which is enabled for writing 

Address space 0…FFH 

The EEPROM-register in ADDR is enabled for just one write instruction. 

It is necessary that the three commands WRITE EEPROM WR-enable, WRITE EEPROM data and WRITE 

EEPROM address are done in that order and immediately after each other. When the time in between the 

first command to the third command is more than 90ms then nothing will be written in the EEPROM. This 

process protects from an unwanted change of the EEPROM. 

The part of the EEPROM that the transceiver doesn’t use (address 0D0H…0FEH) can be used free from the 

application. The calibration values of the transceiver, diverse constants like the configuration are stored in 

this EEPROM as well and are accessible to the application. 

The writing protection EE_WRPROT for the EEPROM is on the EEPROM-address FFH. 

Every one of the 8 bits of the EEWRPROT controls an EEPROM part as follows: 

Bitn = 0: Address range is writable and readable (factory setting) 

Bitn = 1: Address range is not writable and only readable 

EE_WRPROT, Bit0 address 00H...1FH Calibration value frequency and RSSI 

EE_WRPROT, Bit1 address 20H...6FH Calibration value temperature compensation 

EE_WRPROT, Bit2 address 70H...8FH Calibration value reserve 

EE_WRPROT, Bit3 address 90H...9FH Hardware constant 

EE_WRPROT, Bit4 address A0H...AFH Software constant 

EE_WRPROT, Bit5 address B0H...CFH current transceiver configurations 

EE_WRPROT, Bit6 address D0H...FEH free usable for applications 

EE_WRPROT, Bit7 address FFH...FFH EE_WRPROT (this byte) 

The write protection EE_WRPROT only applies for the access with the commands WRITE EEPROM and not 

for the other WRITE commands which also write in the EEPROM. 

Note: 

• Even if the whole EEPROM is free to write in, only the to the application assigned block can be used 

(address 0D0H…0FEH) 

• When the application uses the EEPROM as memory then set EE_WRPROT on b’10111111’ = BFH to 

protect the EEPROM from unwanted changes. 

• After bit7 of EE_WRPROT in EEPROM is set on 1 then the writing protection as a whole can’t be 

changed anymore. Therefore this command has to be used deliberately! 

• When other EEPROM-data e.g. the calibration values were changed then the transceiver might be 

unusable and has to be recalibrated from the manufacturer. But if the calibrations data were saved by 

the user then they can be written in the EEPROM again. 

Be careful with the EEPROM writing function and don’t change the working calibration! It is recommended to 

only write the EEPROM-part to the address D0H…FFH. 

See WRITE EEPROM data and WRITE EEPROM address. 

_____________________________________________________________________________________


_____________________________________________________________________________________ 

Functional name WRITE EEPROM data Function 2EH 

Functional call 0B0H, 2EH, DATA 

DATA EEPROM data byte which should be saved in the previous enabled 

address for writing. 

Answer 2EH, DATA 

Data byte for the EEPROM-register to the previous defined address. The DATA will be written in the 

EEPROM after receiving the third command. 

See WRITE EEPROM WR-enable and WRITE EEPROM address. 

_____________________________________________________________________________________ 

Functional name WRITE EEPROM address Function 2FH 

Functional call 0B0H, 2FH, ADR 

ADR confirmation of the EEPROM address which is enabled for writing. 

Address space 0…FFH 

Answer 2FH, ADR 

The previous transfused DATA-byte will be saved in the EEPROM now if the ADR matches to the address 

transfused in the first command and if the three commands arrive within max. 90ms. 

See WRITE EEPROM WR-enable and WRITE EEPROM address. 

_____________________________________________________________________________________


Functional group REPORT 

The automatic outputs happen in the baud rate with which the last configuration was made. They will only be 

output when the transceiver is in the configuration mode (MODE-on high). 

_____________________________________________________________________________________ 

Functional name REPORT READY (automatic data output) 

Functional call automatically after power up, MCLR\ - Reset or wake up 

Automat. output: 30H, RDY_state 

RDY_state 00H Micro controller ready after power up or MCLR\ - Reset, check sum 

calibration values OK (takes normally 170ms by 16MHz respectively 180ms 

by 8MHz µP clock frequency). 

01H Micro controller ready after wake up. 

80H Micro controller ready after Power up or MCLR\ - Reset, check sum 

calibration values wrong! 

Shows that the micro controller of the transceiver is ready. Depending on the configuration of the transceiver 

it takes a while until the HF-part is absolutely ready as well (3ms by 19.2kbit/s RF data rate, 5ms by 2.4kbit/s 

RF data rate). 

It will be shown after a power up or MCLR\ - reset in the RDY_status when then the calibration values were 

changed in the EEPROM. 

The automatic output of REPORT READY happens in the baud rate with which the last configuration was 

made. They will only be output when the transceiver is in the configuration mode (MODE- on high). 

Note: An autonomous calibration is accomplished by the power up and MCLR\ - reset and it is repeated up 

to 5x in case of a failure. When the calibration can’t be finished successfully then RDY_status = 00H 

(respectively 80H) will be output anyway. 

The result of the calibration can only be established with the calibration command. 

_____________________________________________________________________________________


Functional group ERROR 

_____________________________________________________________________________________ 

Functional name ERROR 

Functional call answer to invalid functions or functional value. 

Automat. output: 38H, ERR_code 

ERR_code 00H invalid function (Byte2) 

01H invalid functional value (Byte3) 

Shows that the transceiver can’t accomplish the command. 

The transceiver responds to every configuration. When no valid command is recognized then an error code 

will be output so that the command can be repeated. 

_____________________________________________________________________________________


Factory setting 

The transceiver modules are delivered with following configuration in the EEPROM: 

Function Value Description 

Frequency RX 01H 433.0625 MHz respectively. 868.0125 MHz 

Frequency TX 01H 433.0625 MHz respectively. 868.0125 MHz 

RF data rate 04H 19.2 kbit/s 

RS232 baud rate 04H 19.2 kBaud 

Power up mode 25H Continue after Wakeup 

Run after power up 

All pin stay unchanged 

Power control 03H LED Transceiver ON 

HF-part Transceiver ON 

Automat. recalibration control 01H Recalibrates automatically by ∆T = 20°C 

Data format 03H CRC16 ON 

Handshake ON 

Fast send OFF 

RSSI of the telegram not output 

No signal condition-RSSI not output


Coding marking of the transceiver module 

Example type plats: 

TRX433-10-C2 

S:02 40 07 Lot:16 08 

46 08 / DS 200 . 

TRX433-10-C2: 

S:02 40 07 Lot:16 08 

46 08 / DS 200 

Software version 1 = Softwarevers. 1 (refered to software type) 

2 = Softwarevers. 2 (refered to software type) 

3 = Softwarevers. 3 (refered to software type) 

4 = … 

Family code A = Radio modem 

B = Direct mode 

C = Byte mode 

D = .. 

Option code 0 = 16MHz / 3.3V / loop filter 19.2kbaud 

1 = 8MHz / 3.0V / loop filter 19.2kbaud 

2 = 16MHz / without volt. reg. / loop filter 19.2kbaud 

(Hardware version) 3 = 8MHz / without volt. reg. / loop filter 19.2kbaud 

4 = 8MHz / 3.3V / loop filter 19.2kbaud 

5 = … 

Module type 1 = With CC1020 / PIC16F648A 

2 = … 

Frequency band 433 = 433.0625 - 434.7875MHz 

868 = 868.0125 - 869.9875MHz 

915 = 914.0125 - 915.9875MHz 

Transceiver module TRX = Transceiver module 

Hardware version = Option code + module type 

Lot-number => Production lot 

Software version => Software version transceiver 

Serial number => Unique address (serial number of software) 

Alias => Alias of the programmer 

Programming date => Date of burning the flash memory


CE declaration of conformity

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