STM32Fx external input counting and triggering ADC

[priven]

Hi,

I have a PWM signal input to STM32Fx MCU, I would like to count the number of pulses and trigger ADC on each rising edge of the PWM.

If I use the input as the clock source for the Timer I don't know how to generate a trigger to the ADC on each pulse without using GPIO EXTI

Please assist,

Michael

[Tesla DeLorean]

Find a TIM where the TIMx_CHx can trigger an ADC, and be routed the external count clock. This, or an Indirect (CH1<->CH2) input capture method should work.

[priven]

Hi Clive,

Thank you for your replay.

From what I understand ADC is triggered by TIM-TRGO or TIM-CC or Ext_IT, and for counting I need to use TIM_Base with the clock being my input?

Maybe I can use TIMx-CH1 as input, than split it to TI1FP1 and TIFP2 set CC_register_1 to base mode and CC_register_2 to capture mode with period of 1?

[Tesla DeLorean]

Don't know what part you're using.

The input capture does CCR2 = CNT, it wouldn't really matter what CNT was doing, which presumably be a maximal setting, as you would just be using it as a trigger event. The ADC would explicitly have support for TIMx_CHx, or be mapped at the TIM to be TIMx_TRGO

The Reference Manual for the part should have a list of trigger sources.

[S.Ma]

You can have your ADC PWM pulse go directly to ADC trigger pin AND the timer if you wish to count periods. If ADC uses DMA to automatically fill a buffer, by simply checking DMA counters, you'll be able to know how many pulses and how many ADC sampled data are in the buffer.

[priven]

Nice work-around, I'll consider it

Thanks