CC1101 asynchronous mode problem

Hi,

We are using CC1101 with MSP430F5xxx to communicate with “strange” device. We send a question and the device sends a response. It is always the same question, and the answer also should be the same. But randomly we receive incorrect data. On oscilloscope it looks like additional bit/bits appears in receiving frames. They don’t look like glitches nor jitters – just shorter bits.

We work on 433MHz; use asynchronous serial mode; 2,4kbd; RX filter BW=200kHz; 2-FSK modulation; deviation 6,3kHz. Below all our register settings.

We have another transceiver which work properly all the time and that’s why we assume that “strange” device always responses in the same way. We have tried many other registers settings, used another CC1101 module, antennas, tried to incorporate pull-ups, pull-downs and RC filters on uart lines and a few other things, but with no luck. And we don’t know what to do else.

Maybe someone faced with similar problem or registers settings are wrong? We ask for help with our problem.

Thanks in advance.

// Rf settings for CC1101

const RF_SETTINGS g_CC1100RFSettingsItron =

{

    0x0D,  // IOCFG2        GDO2 Output Pin Configuration-

    0x2E,  // IOCFG1        GDO1 Output Pin Configuration

    0x2D,  // IOCFG0        GDO0 Output Pin Configuration-

    0x07,  // FIFOTHR       RX FIFO and TX FIFO Thresholds

    0xD3,  // SYNC1         Sync Word, High Byte

    0x91,  // SYNC0         Sync Word, Low Byte

    0xFF,  // PKTLEN        Packet Length-

    0x04,  // PKTCTRL1      Packet Automation Control-

    0x32,  // PKTCTRL0      Packet Automation Control-

    0x00,  // ADDR          Device Address-

    0x00,  // CHANNR        Channel Number-

    0x06,  // FSCTRL1       Frequency Synthesizer Control-

    0x00,  // FSCTRL0       Frequency Synthesizer Control-

    0x10,  // FREQ2         Frequency Control Word, High Byte

    0xAF,  // FREQ1         Frequency Control Word, Middle Byte

    0x78,  // FREQ0         Frequency Control Word, Low Byte

    0x86,  // MDMCFG4       Modem Configuration-

    0x83,  // MDMCFG3       Modem Configuration-

    0x04,  // MDMCFG2       Modem Configuration-

    0x22,  // MDMCFG1       Modem Configuration-

    0xF8,  // MDMCFG0       Modem Configuration-

    0x20,  // DEVIATN       Modem Deviation Setting-

    0x07,  // MCSM2         Main Radio Control State Machine Configuration

    0x30,  // MCSM1         Main Radio Control State Machine Configuration

    0x18,  // MCSM0         Main Radio Control State Machine Configuration-

    0x16,  // FOCCFG        Frequency Offset Compensation Configuration-

    0x6C,  // BSCFG         Bit Synchronization Configuration-

    0x07,  // AGCCTRL2      AGC Control-

    0x47,  // AGCCTRL1      AGC Control-

    0x91,  // AGCCTRL0      AGC Control-

    0x87,  // WOREVT1       High Byte Event0 Timeout

    0x6B,  // WOREVT0       Low Byte Event0 Timeout

    0xF8,  // WORCTRL       Wake On Radio Control

    0x56,  // FREND1        Front End RX Configuration-

    0x10,  // FREND0        Front End TX Configuration-

    0xE9,  // FSCAL3        Frequency Synthesizer Calibration-

    0x2A,  // FSCAL2        Frequency Synthesizer Calibration-

    0x00,  // FSCAL1        Frequency Synthesizer Calibration-

    0x1F,  // FSCAL0        Frequency Synthesizer Calibration-

    0x41,  // RCCTRL1       RC Oscillator Configuration

    0x00,  // RCCTRL0       RC Oscillator Configuration

    0x59,  // FSTEST        Frequency Synthesizer Calibration Control

    0x7F,  // PTEST         Production Test

    0x3F,  // AGCTEST       AGC Test

    0x81,  // TEST2         Various Test Settings-

    0x35,  // TEST1         Various Test Settings-

    0x09,  // TEST0         Various Test Settings-

};