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maier
maier
Associate
March 30, 2014
Question

STM32F4 ADCs triggerd by TIM1 possible?

  • March 30, 2014
  • 3 replies
  • 909 views
Posted on March 30, 2014 at 18:34

Hello,

at first, I try to explain my target functinality:

-TIM1 generates a 3PH Center aligned PWM

- the ADCs are configured in triple mode, some channels are converted and the DMA generates an Interrupt when the Transfer of data to RAM has finished (regular channels)

-TIM1 should Trigger the sampling sequence of the ADCs when 0, Period, or both (Software selectable)

What is working:

-the timer is configured proper an generates the PWM pattern

-the ADCs and DMA work, but only with Software Trigger

The question:

Is it possible to configure TIM1 to generate the Trigger for the ADCs in that way?

The Statements ''TIM1_CHx Event'' in RM0090 on page 396 are not clear to me. It seems to me, that a new conversion is immediately started, after the last has finnished.

Thanks in advance for your help!

#adc #trog #triple-mode #dma
This topic has been closed for replies.

3 replies

Tesla DeLorean
Tesla DeLorean
Guru
March 30, 2014
Posted on March 30, 2014 at 23:47

Triple mode implies they all trigger at the same time, some how I think you want them phase aligned with the respective channels.

You should be able to configure each of the three ADC with a different channel, and different trigger TIM1_CH1, TIM1_CH2_ TIM1_CH3, and you'll need three independent DMA, or IRQ
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maier
maierAuthor
Associate
March 31, 2014
Posted on March 31, 2014 at 06:21

Hi Clive,

the three PWM-Channels are running with no Phase shift, simmilar to the Picture (sorry for Picture source, Google did it ;) :(

http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/908/6036.pwm_5F00_cent.JPG

I want all regular ADC channels on all ADCs converted at PWM Counter == 0, Counter == ADD or both.

When does the ''TIM1_CHx Event'' Trigger the ADC? I can't find further Information for this Events...

Is it right, that the Trigger for triple mode ADC are only the ADC1 ones?
Tesla DeLorean
Tesla DeLorean
Guru
March 31, 2014
Posted on March 31, 2014 at 15:08

You should be able to start the conversion on multiple channels using the trigger. You only have a single trigger, although you can presumably reconfigure it on the fly.

The conversions on an ADC will occur one after another at the sampling rate, in non-continuous mode it will stop after the list is enumerated.

In Triple mode the triggering is mastered by ADC1, but you really want all the ADC configured in a balanced fashion. In this mode you get 3 channels sampled in a synchronous fashion.

For a TIM1 Channel1 Trigger, it should occur when TIM1->CNT == TIM1->CCR1
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