ADC and DAC xxx_timed() methods can't be used concurrently #1129

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1. ul5255 commented on Feb 22, 2015

   

   ul5255

   on Feb 22, 2015

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   I'd suggest to allocate one timer to the ADC(s) and a separate timer to the DAC(s).
2. dpgeorge commented on Feb 22, 2015

   

   dpgeorge

   on Feb 22, 2015

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   I'd suggest to allocate one timer to the ADC(s) and a separate timer to the DAC(s).

   Yes, that's a reasonable thing to do. Could even allow to pass a timer object in as a kwarg to select the timer, with default being tim6.
3. peterhinch commented on Mar 6, 2015

   

   peterhinch

   on Mar 6, 2015

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   That has the advantage of generality: for example you might want to allocate a timer to each DAC instance to enable them to output asynchronously.
4. ul5255 commented on Apr 27, 2015

   

   ul5255

   on Apr 27, 2015

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   Should I should go ahead and implement this? If yes: What is the proper way of doing that? I have another pull request (#1130) which is untouched since 22-FEB-2015 even though I thought I followed the instructions for pull requests. Implementing different timers for DAC and ADC is certainly more involved.
5. dpgeorge commented on Apr 27, 2015

   

   dpgeorge

   on Apr 27, 2015

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   @ul5255 yes this is something you can try to implement. I didn't yet because it's difficult :) Especially since DMA restricts which timers work with which peripherals. And also I want to make ADC.read_timed work with DMA.

   Please feel free to start thinking/hacking on these ideas. Eg a good start is to simply list all the timers and DMA channels for DAC and ADC and see which ones work with each other.
6. dpgeorge

   added a commit that references this issue on Jul 21, 2015

   stmhal: Allow DAC.write_timed to take Timer object in place of freq.

   ...

   abc24c1
7. dpgeorge commented on Jul 21, 2015

   

   dpgeorge

   on Jul 21, 2015

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   DAC now allows you to specify a different timer for write_timed, so both ADC and DAC can work together (ADC still uses Timer(6) always).

   Would be nice to be able to specify timer for ADC similar to DAC, so leaving this issue open until that is implemented.
8. bmentink commented on Jul 21, 2015

   

   bmentink

   on Jul 21, 2015

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   Can you also specify a different timer for each DAC channel? Is the current change checked in, I would like to try it.
9. dpgeorge commented on Jul 21, 2015

   

   dpgeorge

   on Jul 21, 2015 via email

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   Yes and yes. See the most recent commits.
10. dpgeorge

    added a commit that references this issue on Jul 22, 2015

    stmhal: Allow ADC.read_timed to take Timer object in place of freq.

    ...

    7693ef3
11. dpgeorge commented on Jul 22, 2015

    

    dpgeorge

    on Jul 22, 2015

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    ADC.read_timed now allows to specify a timer to use for the triggering. For example:

    adc = pyb.ADC(pyb.Pin("X19"))
    buf = bytearray(100)
    tim = pyb.Timer(2, freq=100)
    adc.read_timed(buf, tim)

    You can use any timer to set the read frequency. You can then use a different timer (or even the same one if you want the same frequency) for DAC.write_timed.
12. dpgeorge

    closed this as completedon Jul 22, 2015
13. bmentink commented on Jul 22, 2015

    

    bmentink

    on Jul 22, 2015

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    Terrific! .... now all we need is DMA support for the Timer and it will be game-set-and-match ;)