AM2634-Q1: How to Start Multi-Channel DMA ADC Conversion via Software in adc_soc_continuous_dma Example

Rahul Dahiya

Part Number: AM2634-Q1

Tool/software:

Hi TI Team,

I am working with the adc_soc_continuous_dma example from the TI SDK. I noticed that although multiple channels selected in the .syscfg file, the example only runs once and collects data from just one channel. The conversions, as per the example, are triggered by the EPWM timer.

My main questions are:

1. Is there a Software API (similar to ADC_forceMultipleSOC) to start DMA-based ADC conversions for multiple channels at once?
2. How can I trigger a new DMA acquisition cycle via software after the DMA ISR indicates all samples are collected, instead of relying on continuous hardware triggering?
3. What are the recommended steps or APIs to re-initiate the DMA and ADC conversions for all selected channels when using software triggers?

My goal is to:

1. Select multiple ADC channels.
2. Trigger conversions and corresponding DMA transfers in software.
3. Process the data in the DMA ISR when complete.
4. Restart the acquisition via software upon ISR or user input.

Any guidance or example code for this use case would be very helpful!

Thanks in advance.

Thanks,
Rahul

1 month ago

0 Fleenor 1 month ago

TI__Mastermind 23023 points

Hi Rahul,

Thanks for reaching out. I am looking into this for you and will get back to you by the end of the week.

Best Regards,

Zackary Fleenor

0 Fleenor 1 month ago

TI__Mastermind 23023 points

Hey Rahul,

Sorry for the delayed response here.

Q1) What do you mean by DMA-based ADC conversions? You can program the ADC Start of Conversion block to use a variety of trigger events to begin sampling.Including the ADC_setupSOC() API link below for reference.

https://software-dl.ti.com/mcu-plus-sdk/esd/AM263X/latest/exports/docs/api_guide_am263x/group__DRV__ADC__MODULE.html#ga476ce05331b08ff2fec27cbf5bca73fd

Q2) The EDMA_enableTransferRegion() API supports 3 trigger types: EDMA_TRIG_MODE_MANUAL, EDMA_TRIG_MODE_QDMA, and EDMA_TRIG_MODE_EVENT.

https://software-dl.ti.com/mcu-plus-sdk/esd/AM263X/latest/exports/docs/api_guide_am263x/group__DRV__EDMA__MODULE.html#ga50ac4ed1bc5df32e3476e7fdd67280a4

What is meant by "relying on continous hardware triggering" in this context?

Q3) I am going to loop in a fellow software expert here to provide more feedback for this software triggered use-case.

Thank you for your patience.

Best Regards,

Zackary Fleenor

0 Rahul Dahiya 1 month ago in reply to Fleenor

Prodigy 120 points

Hi Zackary,

In the adc_soc_continuous_dma example, I’ve noticed that samples are collected for one channel, even when multiple channels are selected in the SYSCFG file. Ideally, if 5 channels are selected and the total sample count is set to 1000, each channel should show 200 samples. However, in the current example, sampling is performed for single channel.

Could you clarify:

How can we configure the example so that each channel gets an equal share of samples based on the selected channel count?
What is the recommended approach to re-trigger the sampling process, so we can capture another set of samples after the initial run? Currently, the example only runs once and doesn’t restart automatically.

Looking forward to your guidance on proper sample distribution and triggering repeated data collection.

Thanks,
Rahul