FTM-PDB-ADC trigger goes wrong on S32K148

[renhaochen]

Hi, I'm developing a DC motor control project based on S32K148, and I basically follow the MTR-148 example code to write code. Now the problem is that adc interrupt randomly stopped after successful working few seconds or few minutes.

Since I use the FTM-PDB-ADC trigger sequence, I had tried to change PDB MOD, Delay time...etc, but the interrupt is acting the same, sometimes even not work since beginning. When I check the register after the interrupt stopped, the COCO flag of last ADC channel (which also is configured to generate interrupt) is not set, but the COCO flag before this channel had all set.

Do you have any idea to this problem? Or is there any reference could help to this problem?

There's my initial settings below:

FTM with 80us,12.5kHz

TRGMUX:

PDB:

ADC:

Thank you very much!!

[PetrS]

Hi,

do you see some sequence error reported on PDB_CH0S?
Generally, be sure PDB pretriggers delays are properly set to be sure a conversion is finished between two petriggers. Also be sure ADC result registers are always read after conversion.
You can try to use DMA to read all result registers, trigger DMA from PDB using IDLY set for right time with respect of expected last conversion.

BR, Petr

[renhaochen]

Hi @PetrS ,

Thank you for the fast replying,

I checked PDB0.CH0S register and it shows Sequence error not detected.

And I had tried to set DMA enable configuration for ADC module and add DMA channel for ADC0, it works fine until I enable UART0 through DMA. While UART0 is working ADC interrupt goes unstable again. Is this one of the issue?

Also you had mentioned " trigger DMA from PDB using IDLY ", is there more specific settings information I could know? For now I just simply configured ADC and DMA on Processor Expert tool, and PDB initial codes shows below:

Thank you !

[PetrS]

Hi,

I am not aware of the example for trigger DMA from PDB. Anyway you should do

- disable DMA from ADC and enable DMA from PDB within ADC and PDB components
- assign PDB as request to DMA channel in DMA component
- use PDB_SetValueForTimerInterrupt to configure IDLY register, to specify a time when DMA is triggered
- configure DMA channel to read all ADC result registers upon single DMA request

BR, Petr

[renhaochen]

Hi @PetrS :

I had followed the first 3 steps, but I don't really get the 4th step,

I only use ADC_DRV_GetChanResult() function to get the result, and it end up the same.

I'm a little confuse with this part, It would be better if you could explain more details,

Thank you!

Best regards,

[PetrS]

Hi,

when using DMA to read result registers then you need not to use ADC_DRV_GetChanResult() function.
You can try to refer to https://community.nxp.com/t5/S32K-Knowledge-Base/Example-S32K144-PDB-ADC-DMA-S32DS-ARM-2018-R1/ta-p/...
to see how DMA is used. It is set up differently, to be triggered from ADC directly, but you can modify it for your need. 

BR, Petr