IWR6843: Abnormal ADC data occurs when radar is runnung.

tungyen wu

Prodigy 20 points

Part Number: IWR6843
Other Parts Discussed in Thread: , AWR1642, AWR1642BOOST, AWR6843ISK, MMWAVEICBOOST

Hi,

I am testing radar system and I find there are some abnormal data in a chirp from rawdata.

The data are logged after eDMA triggerd and showed as following pictures.

The eDMA setting refer to Short Range Radar demo project.

There are 128 chirps in a frame and each chirp contains 256 smaple.

The following code is how I logged the data in "MmwDemo_interChirpProcessing".

MmwDemo_startDmaTransfer(obj->edmaHandle[EDMA_INSTANCE_B],
SRR_SF0_EDMA_CH_1D_IN_PING,
SRR_SF1_EDMA_CH_1D_IN_PING,
subframeIndx);

if(obj->chirpCount==0)
{
int i;
int16_t *src = (int16_t *)&obj->adcDataIn[pingPongId(0) * obj->numRangeBins];
for(i=0; i<obj->numAdcSamples*2; i++)
{
obj->debugSample[i] = src[i];
}
}

This problem occurs after radar start running several hours.

Once the adc goes wrong, it will not go back eventually.

Please help me finding out the root cause of the abnormal adc data.

Thanks,

over 2 years ago

0 Alec May over 2 years ago

TI__Genius 17265 points

Hi,

So to be clear, you have modified the SRR demo to work on the IWR6843, and you see the ADC values get abnormal after several hours, and that they never return to normal values, correct?

Best Regards,
Alec

0 tungyen wu over 2 years ago in reply to Alec May

Prodigy 20 points

Yes. I have checked the voltage and oscillator on the IWR6843.

0 Alec May over 2 years ago in reply to tungyen wu

TI__Genius 17265 points

Hi,

Understood. Is this the only change which you have made to the demo software? And is this a TI Evaluation Module or is it running on custom hardware? I am just trying to understand the scope to determine whether it is something which can be reproduced on our end.

Best Regards,
Alec

0 tungyen wu over 2 years ago in reply to Alec May

Prodigy 20 points

Is this the only change which you have made to the demo software?

I add a function to detect if there is a problem in detMatrix array and target id association in EKF.

And is this a TI Evaluation Module or is it running on custom hardware?

We made our custom borad according to iwr6843isk evm.

0 Alec May over 2 years ago in reply to tungyen wu

TI__Genius 17265 points

Hi,

To try to eliminate some of the potential sources of issue, could you try running the same firmware on a TI evaluation module?

Best Regards,
Alec

0 tungyen wu over 2 years ago in reply to Alec May

Prodigy 20 points

Sure. Since our custom radar borad transfer data by SPI rather than uart, It takes me some time to modify the project code.

0 Alec May over 2 years ago in reply to tungyen wu

TI__Genius 17265 points

Understand. Take your time and let me know what results you find or if you have any questions for me.

Best Regards,
Alec

0 tungyen wu over 2 years ago in reply to Alec May

Prodigy 20 points

I have tested the project and logged the IQ(the first picture).

I found a little part of IQ data on the custom board were wrong when the system started.

0 E. Shareef over 2 years ago in reply to tungyen wu

TI__Genius 16440 points

What are you using for your raw ADC data capture?

-Shareef

0 tungyen wu over 2 years ago in reply to E. Shareef

Prodigy 20 points

Because the heatmap(detMatrix) is weird in output, I want find the cause.

The iwr6843 does not support lowpower mode while the original srr project uses this setting, so I change the lowpower mode to "LP_ADC_MODE_REGULAR".

Is there any more setting should be changed when I port the project from AWR1642 to IWR6843?

0 aozer over 2 years ago in reply to tungyen wu

TI__Mastermind 30715 points

Hello Tungyen,

If I understand correctly, you are using the same code form AWR1642 on your custom IWR6843 design?

How are you capturing the raw data? Is it possible for you to do a data capture with mmWave Studio and DCA1000 on your custom design and see if the data is corrupted?

Regards,

Adrian

0 tungyen wu over 2 years ago in reply to aozer

Prodigy 20 points

It's hard to capture data with mmWave Studio and DCA 1000, since our custom board does not have the interface.

I now create a memory block to log data of first chirp in every frame and transfer them out with SPI.

0 Alec May over 2 years ago in reply to tungyen wu

TI__Genius 17265 points

Hi,

Stepping back a bit. Can you clarify whether the software used when comparing the custom board to the EVM above was the same software on both boards? Or was there significant differences in the SW and/or the method used to capture the data?

Best Regards,
Alec

0 aozer over 2 years ago in reply to tungyen wu

TI__Mastermind 30715 points

In addition to the above question, can you confirm which EVM you are testing on? Are you testing on the AWR1642BOOST or the AWR6843ISK?

Regards,

Adrian

0 tungyen wu over 2 years ago in reply to aozer

Prodigy 20 points

I used IWR6843ISK+MMWAVEICBOOST.

I think I should give the eDMA more time and copy the sample data after "MmwDemo_dataPathWait1DInputData".

0 Alec May over 2 years ago in reply to tungyen wu

TI__Genius 17265 points

Hi,

Can you confirm what firmware you were using during the comparison between your custom hardware and the IWR6843ISK? Was this firmware the same, or were modifications made for the different hardware platforms?

Best Regards,
Alec

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IWR6843: Abnormal ADC data occurs when radar is runnung.