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MSP430FR2433: MSP430FR2433 -----ADC10 issue

SeaFesse
Expert 2690 points

Part Number: MSP430FR2433

Hi TI guys,

I found the ADC10 of FR2433 doesn't works as the user guider says.

The problem happens on  Repeat-Sequence-of-Channels Mode.

As we know, there is no DTC or DMA in FR2433 . Besides, it has only one ADCMEM. so I need your help clear sth.

1) If  I chose the sample trigger source  is TA1 , not by software(ADCSC),  and there're 5 channels in one sequence.

A rising edge of TA ,will trigger the whole sequence or just only one channel ?

In my head , if set ADCMSC bit,  the rising edge of TA will trigger the whole sequence , or , it just trigger only one channel.

   Am I right?

2)

Does it necessary to toggle ADCENC bit after each sequence conversion  completed in Repeat-Sequence-of-Channels Mode?


3)

Keep these precondion in mind,

a) Repeat-Sequence-of-Channels Mode   

b）Trigger by TA ,and TA always runs    

c)  ADCMSC  is NOT set.

When one sequence completed, will another sequence starts automatically ?

Thanks.

  • 0
    Guru 100445 points

    The ADC sequencing for CONSEQ=3 is shown in the User Guide (SLAU445H) Fig 21-16.
    1) With MSC=1, a single TA trigger will start an unending repetition of sequences (up-arrow to the left). Further TA triggers will effectively be ignored.
    2) No need to toggle ENC, regardless of the MSC setting. (Up-arrows to the left and inner-right).
    3) With MSC=0, each TA trigger will cause a single conversion (in sequence), and the sequence will restart once finished. (Up-arrow inner-right)

    I use (3) routinely with a TA period divided by 5 (in your case), so as to avoid the ADCMEM race (ie, no DMA). I don't get "pseudo-simultaneous" sampling in the burst, but that's ultimately a consequence of the ADCMEM race, not the technique.

    To have a single TA trigger run a full burst, you need to use CONSEQ=1 with MSC=1 [UG Fig 21-12], which does require toggling ENC each round. But now you're back to the ADCMEM race.

    What incorrect behavior are you observing?

    [Edit: Fixed some wording goofs.]

  • 0
    TI__Intellectual 1000 points

    You can see details in below figure:

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