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MSPM0G3519: MSPM0G3519: ADC channel mapping

Khanh Doan
Prodigy 150 points

Part Number: MSPM0G3519
Other Parts Discussed in Thread: MSPM0G3218

Hi TI Team,

I have two question regardings ADC Channel mapping:

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1/ If I want to measure VREF- and VREF+ , do I need to configure using external reference. Is it possible that I use VDD as voltage reference but can still measure the ADC from these 2 pins ? 

I have another chip MSPM0G3218 , and in the datasheet it mentioned the VREF1 and VREF2 ? What are their meaning ? It is VREF+ and VREF- 

2/ If I choose voltage reference as MCU supply voltage, I guess the ADC value read for channel 15 will be equal to the supply voltage. What will happen it I use external reference, and still measure the supply/battery monitoring ?  (I mean the VDD is not available now, or it must to be available to turn on the chip ?)

  • +1
    TI__Expert 4670 points

    Hi Khanh,

    To answer your questions:

    1. You cannot use the same pins to configure VREF+ and VREF- and configure ADC input channels. To measure VREF it would need to be in the range of 0 = VSSA = VREF- < VREF+ < VDDA otherwise you will only read 0xFF. This can be measured by setting the ADC voltage reference to VDDA as you have mentioned, but you would need to route the VREF+ and VREF- signals to other ADC channels.

    For the MSPM0G3218 there are two separate VREF modules.  One can do both internal and external voltage references while the other can only do internal.

    2. Without VDDA the device will not power on.  Our data sheet specifications for the supply/battery monitor were taken with respect to using an external VREF.

    Best Regards,
    Brian