IWR6843AOP: Questions Regarding profileCfg

Hi Robin, 

RobinSpearhead said:

In the document "\mmwave_sdk_03_06_02_00-LTS\packages\ti\control\mmwavelink\include\rl_sensor.h", at line 713, it states that only even numbers can be used for freqSlopeConst. However, the given limits are odd numbers. Is this a typo?

Yes this appears to be a typo, it should be "integer numbers" instead of "even numbers". However, please note, this comment refers the to the value for ramp slope frequency which is used by the mmWave link layer. This is not the same as what can be sent over CLI via the profileCfg command. The value sent over CLI can be a float value which is then translated to the 16 bit int as below (cli_mmwave.c). 

    /* Translate from MHz/us to [1 LSB = (gCLI_mmwave_freq_scale_factor * 1e6 * 900) / 2^26 kHz/uS]
     * units of mmwavelink format */
    profileCfg.freqSlopeConst        = (int16_t)(atof(argv[8]) * (1U << 26) /
                                                 ((gCLI_mmwave_freq_scale_factor * 1e3) * 900.0));

RobinSpearhead said:

Is there a recommendation or calculation for how far adcStartTimeConst and txStartTime should be apart? This should depend on the max. unambiguous range, correct?

There is a ramp-timing calculator available in the 'RadarStudio' tool from the DFP package that should aid you in avoiding the settling region of the adc. The sampling rate, the ADC mode, the slope of the ramp all affect the amount of settling that is seen in a chirp. 

RobinSpearhead said:

What is the minimum idleTimeConst? Is it dependent on the bandwidth of the chirps?

The ramp down time does slightly depend on the bandwidth and the idle time configured should be enough to avoid the ramp down time. You can check the timing through the Ramp Timing Calculator in mmWave Studio 2.1. Alternatively, you can also use the Advanced Chirp Design and Tuning tab of the mmWave Sensing Estimator to verify this as well. However, your question specifically mentions idleTimeConst  which is the value passed to mmWave link layer. The valid range for idleTimeConst is 0 to 524287 (in units of 10 ns).

Best Regards,

Josh

HI Robin, 

My apologies, the mmWave Studio has limited functionality without DCA1000. Please use the mmWave Sensing Estimator tool instead.

Best Regards,

Josh