CC1101: WOR just using carrier

I did a test where I used the recommended settings from SmartRF Studio for the 2.4 kbps PHY, and then I enabled WoR with a 1 s wakeup interval, 12.5% duty cycle, and an CS threshold of -70 dBm (for test purposes)(see table 32 in the data sheee).

Settings from Studio, and code is shown below:

// Address Config = No address check 
// Base Frequency = 867.999939 
// CRC Autoflush = false 
// CRC Enable = true 
// Carrier Frequency = 867.999939 
// Channel Number = 0 
// Channel Spacing = 199.951172 
// Data Format = Normal mode 
// Data Rate = 2.39897 
// Deviation = 5.157471 
// Device Address = 0 
// Manchester Enable = false 
// Modulated = true 
// Modulation Format = GFSK 
// PA Ramping = false 
// Packet Length = 255 
// Packet Length Mode = Variable packet length mode. Packet length configured by the first byte after sync word 
// Preamble Count = 4 
// RX Filter BW = 58.035714 
// Sync Word Qualifier Mode = 30/32 sync word bits detected 
// TX Power = 0 
// Whitening = false 
// PA table 
#define PA_TABLE {0x50,0x00,0x00,0x00,0x00,0x00,0x00,0x00}

static const registerSetting_t preferredSettings[]= 
{
  {CC1101_IOCFG0,      0x06},
  {CC1101_FIFOTHR,     0x47},
  {CC1101_PKTCTRL0,    0x05},
  {CC1101_FSCTRL1,     0x06},
  {CC1101_FREQ2,       0x21},
  {CC1101_FREQ1,       0x62},
  {CC1101_FREQ0,       0x76},
  {CC1101_MDMCFG4,     0xF6},
  {CC1101_MDMCFG3,     0x83},
  {CC1101_MDMCFG2,     0x13},
  {CC1101_DEVIATN,     0x15},
  {CC1101_MCSM0,       0x18},
  {CC1101_FOCCFG,      0x16},
  {CC1101_WORCTRL,     0xFB},
  {CC1101_FSCAL3,      0xE9},
  {CC1101_FSCAL2,      0x2A},
  {CC1101_FSCAL1,      0x00},
  {CC1101_FSCAL0,      0x1F},
  {CC1101_TEST2,       0x81},
  {CC1101_TEST1,       0x35},
  {CC1101_TEST0,       0x09},
};

void main(void)
{
    // Initialize MCU and peripherals
    initMCU();

    // Write radio registers
    registerConfig();
    
    uint8 writeByte;
    
    // WoR settings for 1 s wakeup interval, 12.5% duty cycle
    writeByte = 0x18; cc1101SpiWriteReg(CC1101_MCSM0,   &writeByte, 1);
    writeByte = 0x38; cc1101SpiWriteReg(CC1101_WORCTRL, &writeByte, 1);
    writeByte = 0x00; cc1101SpiWriteReg(CC1101_MCSM2,   &writeByte, 1);
    
    writeByte = 0xB3; cc1101SpiWriteReg(CC1101_AGCCTRL2, &writeByte, 1); // CS threshold = -70dBm
    
    writeByte = 0x69; cc1101SpiWriteReg(CC1101_IOCFG0, &writeByte, 1); // Debug signal to show when device is awake
    writeByte = 14;   cc1101SpiWriteReg(CC1101_IOCFG2, &writeByte, 1); // CS  signal (RSSI > -70 dBm)
    
    trxSpiCmdStrobe(CC1101_SWOR);
    
    while(1);
}

For testing purposes, I had a transmitter that transmitted for around 2 s every time a button was pushed.

As you can see prom the plots, the radio wakes up 125 ms every second. Every time a 2 s carrier is transmitted, the CS signal will be asserted.

From your description, this is how I understand you want your system to work.

Once you have gotten it to work with characterized settings and a strict CS threshold, you can start changing your settings and thresholds.

In the data sheet we only have CS threshold settings for the 2.4 kbps and the 250 kbps PHYs, so if you use something other than that, you need to test different compinations of the  following parameters to find a suitable threshold for your application:

AGCCTRL2.MAX_LNA_GAIN

AGCCTRL2.MAX_DVGA_GAIN

AGCCTRL2.MAGN_TARGE

Siri

The carrier sense signal (IOCFG2 = 14) does not care about what data is being transmitted. It only look at the signal strength, and asserts if the RSSI is above your programmed threshold.

What  SYNC_MODE you use will not affect the CS signal.

I tested the code with both sending packets with long preamble (2 s) and by sending unmodulated data for a given period of time.