Using CC1000 for the Konnex standard

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&KLSFRQ$SSOLFDWLRQ1RWH $1and so on). In this mode the data clock (DCLK) is not used, so the over-sampling and thesynchronisation must be done externally, by a microcontroller, or by an UART.The Konnex protocolA preheader that has a Manchester Violation is used in the konnex standard. TheSynchronous Manchester mode can for this reason not be used in the TX mode of CC1000during transmission of this Preheader.In Rx mode the settling of the averaging filter in CC1000 require a balanced baud in thepreamble. In Manchester mode the chip stream must be ’100110011001…’ during thepreamble to ensure correct bit synchronisation. The Konnex preamble is however a chipstream of ‘0101010101’.PreheaderPreamble Manchester Sync word Postambleviolation15x ‘01’ chip ‘000111’ ‘011010010110’ 2-8 chipsDue to the Konnex preheader, CC1000 must use Synchronous NRZ mode and not useSynchronous Manchester mode. The Manchester coding must then be done in the MCU andthe datarate of this Manchester coded data need a datarate of 32.768 kbaud. Using thesynchronous NRZ mode, the preamble of balanced baud are ‘01010101..’, because the baudrate is the same as the bit rate in NRZ. Further the Manchester violation bit stream can easilybe implemented.In NRZ mode the settling time should be set to 01 to give a settling time of the averaging filterin the demodulator to 32 baud. In NRZ the baud rate is equal to the bit rate, and the Konnexrequire that the receiver are able to receive valid data after the preamble. This preamble is 30baud in NRZ mode, and it is ok for the CC1000 to use SETTLING=01 in MODEM1 Register.CC1000 Rx test for KonnexA preliminary test was performed using the calculated crystal frequency, in order to verify thatRX mode complies with the Konnex standard. During the test, a Signal Generator was used togive the Crystal frequency. The test result is given in the table below.Crystal SeparationMODEM0SensitivityfrequencyBAUDRATE DATA_FORMAT XOSC_FREQ12.586060 80 kHz 101 00 NRZ 01 -96 dBm12.586060 100 kHz 101 00 NRZ 01 -97 dBm12.586060 160 kHz 101 00 NRZ 01 -96 dBmTx data rate offset of 2% gives no effect on the sensitivity.Chipcon AS AN010 Using C1000 for the konnex standard (Rev. 1.0) 2001-11-27 Page 4 of 6
&KLSFRQ$SSOLFDWLRQ1RWH $1The blocking performance of CC1000 is given in the table below.Frequency offset CC1000 Requirement+/- 1 MHz 43 dB 30 dB+/- 2 MHz 49 dB 35 dB+/- 5 MHz 68 dB 50 dB+/- 10 MHz 72 dB 60 dBThe blocking result between +/- 10 MHz offset of 868 MHz is given in figure 1. This indicatesthat CC1000 complies with the blocking requirement of the Konnex standard.80706050dBc403020100855 860 865 870 875 880-10Figure 1: Blocking performance of CC1000 at 868 MHzCC1000 Tx test for KonnexThe synchronous data clock in transmit mode will also be scaled as shown above. The loopfilter bandwidth is adequate for baud rate at 32.768 kbaud but an optimisation of the PLLbandwidth could be done to improve the modulation response. A simple modulation analysiswas performed, and the time versus frequency plot showed a peak-to-peak separation of +/-120 kHz using a programmed frequency separation of 100 kHz. The Konnex require aseparation between 80-160 kHz, and CC1000 complies with the Konnex regarding modulation.In transmit mode the DCLK gives a signal equal to the data rate, and has no duty cycle offset.This informs us that there is no TX jitter on the transmitted signal.SummaryBy using a crystal frequency of 12.586060 MHz with a total accuracy of 11.5 ppm, the datarate and the frequency tolerance of the Konnex standard can be met. The sensitivity is –96dBm also meeting the standard.Chipcon AS AN010 Using C1000 for the konnex standard (Rev. 1.0) 2001-11-27 Page 5 of 6
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Using CC1000 for the Konnex standard

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