I'm confused about transfer adc result to memory with dma

[Piper123]

Hi:

    I want to transfer adc result to memory with dma, but failed. here is my question, on condition that I configed to use software trigger to start a adc conversition, whether using dma to transfer adc data is legal. If using dma to transfer adc data is legal,  is there any example? or how to config dma and adc registers?  

[PetrS]

Hi,

could you please specify a device you have?

BR, Petr

[Piper123]

S32k146uavlq  evb from nxp

[PetrS]

Hi,

yes, it is possible. An SC2[DMAEN] controls if DMA request is generated upon complete conversion

Then you need to config DMAMUX channel to route ADC DMA request to DMA channel and configure DMA channel descriptor to do a moves you need. 

You can refer to below examples, but it uses HW triggering from PDB
non-sdk: https://community.nxp.com/t5/S32K-Knowledge-Base/Example-S32K144-PDB-ADC-trigger-DMA-ISR-S32DS/ta-p/...
sdk: https://community.nxp.com/t5/S32K-Knowledge-Base/Example-S32K144-PDB-ADC-DMA-S32DS-ARM-2018-R1/ta-p/...

BR, Petr

[Piper123]

Hi, PetrS

        I have read the example you give, and compare with my configurations, DMAMUX and DMA configurations have no difference. Then only difference is my project use only DMA channel0, and ADC just use the channel 0 of ADC0.

        I have test the adc and dma separatly,  both adc  dma can work normally. Dma use software trigger mode also can transfer data from ADC0->R[0] to memory. But after I config DMAMUX->CHCFG.SOURCE = 0x2A and anable adc DMAEN bit, it doesn't work. Is there any step I missed?

   Pictures below is some register's value, Please help me check. Thanks.

[PetrS]

Hi,

is the DMAMUX clocked and do you have DMAMUX->CHCFG.ENBL set as well? Or share the code you have.

BR, Petr

[Piper123]

Hi, Petrs
Thanks for your help. I have found the reason of the problem; I configured two dma channels with the same priority and use thte periodic trigger incorrctly.