Version List

Transceiver module TRX433-10C2 / TRX868-10C2 (Vers. 1.0E) 48
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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.
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