IWR6843: 512+ Num of loops

Thanks for the response, does it mean that there is no way to increase the Doppler FFT over the 512 samples barrier? Utilizing the IWR6843 chip. Does it differ to the IWR1863 chip?

Hello Pavel.

Pavel Bartoš said:

hanks for the response, does it mean that there is no way to increase the Doppler FFT over the 512 samples barrier?

Let me confirm this and provide a response by the end of the day tomorrow.

Pavel Bartoš said:

Does it differ to the IWR1863 chip?

This will not differ for the IWR1843, which is what I think you meant, as the firmware for both devices is the same.

Sincerely,

Santosh

Hello Santosh,

number of doppler samples is not defined by ADC samples. ADC samples define just size of Range FFT. Doppler FFT is defined by number of chirp loops. The question remains: what is the maximum number of Chirp loops AKA Doppler FFT size.

Thank you,

Pavel B.

We are able to achieve 512 Doppler FFT loops with this setting:

Hi Pavel.

I understand; I missed the second chirpCfg.  However, what is your channelCfg configured for?  Are you enabling all 3 Tx's?

Sincerely,

Santosh

No, we are using a single Rx and a single Tx, because we have our own radar antenna.

Hello.

As stated in the mmwave_demo_user_guide, there may be some combinations of the chirpCfg and total number of chirps that result in the radar cube/internal buffers and heap size that cause out of memory conditions.  I think having 1 Rx and 1 Tx is ok, but you will have to adjust other parameters to make everything fit in memory.  I have included a screenshot of the note in the SDK user guide for reference.  Can you provide the exact error you are getting from the current configuration?  I presume that you are seeing some CLI error indicating that the device was configured properly?

Sincerely,

Santosh

Hi,

the memory demand is checked during the creation of the parameters on our side. Could you please provide a functioning config (prepared to be sent into the device) that introduces more than 512 Doppler FFT loops to test it on the demo SW? Thank you

Hi Pavel.

Could you please share what error you are encountering when using your current configuration?  If there is no chirp configuration in the SDK or toolbox that meets your requirements, I would recommend using the mmWave Sensing Estimator tool to design your chirp configuration.  I would make sure that the number of chirps you are trying to perform can perform within the frame time you have configured, and if not increase that time.  The sensing estimator tool will highlight all of these points for you once you put your configuration into the tool.

Sincerely,

Santosh

when using this config:

sensorStop
flushCfg
dfeDataOutputMode 1
channelCfg 1 1 0
adcCfg 2 1
adcbufCfg -1 0 1 1 1
profileCfg 0 60 23 7 55.125 0 0 69.1994572591588 0 256 10189.0547263682 0 0 158
chirpCfg 0 0 0 0 0 0 0 1
chirpCfg 1 1 0 0 0 0 0 1
chirpCfg 2 2 0 0 0 0 0 1
chirpCfg 3 3 0 0 0 0 0 1
frameCfg 0 1 254 0 1000 1 0
lowPower 0 0
guiMonitor -1 1 1 1 0 0 1
cfarCfg -1 0 2 8 4 3 0 15 1
cfarCfg -1 1 0 4 2 3 1 15 1
multiObjBeamForming -1 1 0.5
clutterRemoval -1 0
calibDcRangeSig -1 0 -5 8 256
bpmCfg -1 0 0 1
extendedMaxVelocity -1 0
lvdsStreamCfg -1 0 0 0
compRangeBiasAndRxChanPhase 0.0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
measureRangeBiasAndRxChanPhase 0 1.5 0.2
CQRxSatMonitor 0 3 4 79 0
CQSigImgMonitor 0 127 4
analogMonitor 0 0
aoaFovCfg -1 -20 20 -20 20
cfarFovCfg -1 0 0.5 45
cfarFovCfg -1 1 -5 5
calibData 0 0 0
sensorStart

everything works as it is supposed to work. However if we try to increase the number of Chirps:

sensorStop
flushCfg
dfeDataOutputMode 1
channelCfg 1 1 0
adcCfg 2 1
adcbufCfg -1 0 1 1 1
profileCfg 0 60 23 7 55.125 0 0 69.1994572591588 0 256 10189.0547263682 0 0 158
chirpCfg 0 0 0 0 0 0 0 1
chirpCfg 1 1 0 0 0 0 0 1
chirpCfg 2 2 0 0 0 0 0 1
chirpCfg 3 3 0 0 0 0 0 1
frameCfg 0 3 254 0 1000 1 0
lowPower 0 0
guiMonitor -1 1 1 1 0 0 1
cfarCfg -1 0 2 8 4 3 0 15 1
cfarCfg -1 1 0 4 2 3 1 15 1
multiObjBeamForming -1 1 0.5
clutterRemoval -1 0
calibDcRangeSig -1 0 -5 8 256
bpmCfg -1 0 0 1
extendedMaxVelocity -1 0
lvdsStreamCfg -1 0 0 0
compRangeBiasAndRxChanPhase 0.0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
measureRangeBiasAndRxChanPhase 0 1.5 0.2
CQRxSatMonitor 0 3 4 79 0
CQSigImgMonitor 0 127 4
analogMonitor 0 0
aoaFovCfg -1 -20 20 -20 20
cfarFovCfg -1 0 0.5 45
cfarFovCfg -1 1 -5 5
calibData 0 0 0
sensorStart

then this is the console messages output using the mmWave sensing estimator to load the config:

mmwDemo:/>sensorStop
Ignored: Sensor is already stopped

Done

mmwDemo:/>flushCfg
Done

mmwDemo:/>dfeDataOutputMode 1
Done

mmwDemo:/>channelCfg 1 1 0
Done

mmwDemo:/>adcCfg 2 1
Done

mmwDemo:/>adcbufCfg -1 0 1 1 1
Done

mmwDemo:/>profileCfg 0 60 23 7 55.125 0 0 69.1994572591588 0 256 10189.0547263682 0 0 158
Done

mmwDemo:/>chirpCfg 0 0 0 0 0 0 0 1
Done

mmwDemo:/>chirpCfg 1 1 0 0 0 0 0 1
Done

mmwDemo:/>chirpCfg 2 2 0 0 0 0 0 1
Done

mmwDemo:/>chirpCfg 3 3 0 0 0 0 0 1
Done

mmwDemo:/>frameCfg 0 3 254 0 1000 1 0
Done

mmwDemo:/>lowPower 0 0
Done

mmwDemo:/>guiMonitor -1 1 1 1 0 0 1
Done

mmwDemo:/>cfarCfg -1 0 2 8 4 3 0 15 1
Done

mmwDemo:/>cfarCfg -1 1 0 4 2 3 1 15 1
Done

mmwDemo:/>multiObjBeamForming -1 1 0.5
Done

mmwDemo:/>clutterRemoval -1 0
Done

mmwDemo:/>calibDcRangeSig -1 0 -5 8 256
Done

mmwDemo:/>bpmCfg -1 0 0 1
Done

mmwDemo:/>extendedMaxVelocity -1 0
Done

mmwDemo:/>lvdsStreamCfg -1 0 0 0
Done

mmwDemo:/>compRangeBiasAndRxChanPhase 0.0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
Done

mmwDemo:/>measureRangeBiasAndRxChanPhase 0 1.5 0.2
Done

mmwDemo:/>CQRxSatMonitor 0 3 4 79 0
Done

mmwDemo:/>CQSigImgMonitor 0 127 4
Done

mmwDemo:/>analogMonitor 0 0
Done

mmwDemo:/>aoaFovCfg -1 -20 20 -20 20
Done

mmwDemo:/>cfarFovCfg -1 0 0.5 45
Done

mmwDemo:/>cfarFovCfg -1 1 -5 5
Done

mmwDemo:/>calibData 0 0 0
Done

mmwDemo:/>sensorStart


how can we achieve more doppler FFT's? Are you aware of a config that would work for us?

Hello Pavel.

It isn't clear what error you are seeing from the console output, is there anything that is output after the sensorStart or any message after the sensorStart?  If not, it would indicate that the device is crashing.  Have you tried using subFrameCfg and advFrameCfg?  This would allow you to send out four chirps, but it is treated as one chirp as the four chirps are accumulated into that one chirp.  For more info on these cfg commands, you can refer to the sdk user guide.

Sincerely,

Santosh