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MSP430FR5724: ADC sampling issue

Cherry Zhou
Mastermind 22235 points
Part Number: MSP430FR5724

Hi team,

The customer would like to collect the external voltage information for three channels of A3 A4 A5 using multiple samples of the sequential channels.

But as described in manual, only the highest bit can be defined when sampling a sequence channel. The customer would like to know how to resolve this issue by configuring.

Could you help check this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 18090 points

    Hi Cherry,

    Is the customer wanting to sample them out of order or just reset when it gets to A3 instead of A0?

    This is untested but, if you just want to still do them in order you could start at A5 then you can do a check for when the register is now on A3 and reset after A3's check. So this would be a software change just checking what register you are in after taking the sample. 

    If you want to sample them out of order, then there might need to be manual checks instead.

    Below is a screenshot of the ADC10INCHx register which was taken from the MSP430FR57xx Family User's Guide.

    Regards,

    Luke

  • 0 in reply to Luke Ledbetter
    TI__Mastermind 22235 points

    Hi Luke,

    Thanks for your reply.

    The customer's need is to obtain external voltage values for three channels of A3 A4 A5 for a long time, and the starting channel cannot be set for this type of monolithic.

    Luke Ledbetter said:
    sample them out of order

    Also, could you clarify what do you mean here by "sample them out of order"?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Mastermind 22235 points

    Hi,

    May I know is there any updates about the additional question?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Mastermind 18090 points

    Hi Cherry,

    By "sampling out of order", I was asking if they wanted to check A5 then A3 then A4 or some other combination, but it seems like its just A5-A3.

    Its actually more beneficial and faster to just keep the sequential order. If they just read the A5, A4 and A3 channels then store those results and let the readings of A2, A1 and A0 run without storing the result it is faster than resetting. This is due to the hardware in the system providing faster actions than the software changes.

    By highest bit you would set it to A5 here then the readings would take A5-A0 for the sequential channel mode.

    Hope this helps clarify!

    Regards,

    Luke

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