Using single ADC with multiple channels — does timer trigger apply to all channels?

[Rakesh212]

Hi,
I am using one ADC with multiple channels on an STM32 device. I configured a timer trigger (external trigger) for the ADC, but I noticed that the trigger seems to apply to all channels of the same ADC, not just the selected channel.

I would like to confirm:

• Is it true that one ADC has only one trigger source, and all configured channels share that trigger?
• Is it possible to configure different sampling/trigger properties per channel, or is the external trigger common for the entire ADC conversion sequence?

My goal is to use different trigger timing per channel, but I am using only one ADC peripheral.

Thank you.

[MasterT]

Only one trigger to all channels, two mode - one events to convert sequence or conversion triggered separately for each channel in sequence.

You have to come up with more complex trigger processing, using timers input multiplexers. So ADC 'd stay connected to one timer, and this timer selects another sources to generate events. 

[Saket_Om]

Hello @Rakesh212 

STM32 ADC has different scope:
- multi-instance: multimode with ADC1+ADC2
- instance: ADC1, ADC2, ...
- groups: regular, injected (not available on all series, available on STM32H7 you are using)
- channel

Parameters group wise: resolution, ...
Parameters group wise: trigger sources, sequencer, ...
Parameters channel wise: sampling time, mode single ended or differential.
 

Therefore, on STM32H7, you can have 2 trigger sources per ADC instance: one on group regular, one on group injected.
Then, you can distribute channels in regular or injected sequencer.

[Ozone]

> I would like to confirm: ...

The place to go would be the reference manual of the MCU, as usual.