MSPM0G3507: ADC is not working properly, in all setups as expected.

Ankush

Part Number: MSPM0G3507
Other Parts Discussed in Thread: MSP430F2619

Tool/software:

Hi team,

I am testing ADC functionality on both the MSPM0G3507 and MSP430F2619 controllers with the reference voltage configured to 2.5 v.

For an input of 137 mV, I observe the following results:

MSPM0G3507 → ~200 ADC counts
MSP430F2619 → ~228 ADC counts

The theoretical value for a 12-bit ADC with 2.5 V reference is approximately 224 counts. The MSP430 result is close to expectation, but the MSPM0G3507 result is noticeably lower.

I would appreciate your suggestions on this observation, or if there are any specific settings that need to be activated for accurate ADC conversion on the MSPM0.

27 days ago

0 Cash Hao11 26 days ago

TI__Mastermind 46765 points

Hi,

Which demo code you are using? If you are using adc12_single_conversion_vref_internal. You need to check if there is one 1uF cap on the PA23 pin to GND. Using the internal VREF module requires a 1uF cap on the VREF+(PA23) pin on the hardware.

Best regards,

Cash Hao

0 Ankush 26 days ago in reply to Cash Hao11

Intellectual 500 points

yes it is there 1uF cap on the PA23 pin to GND

0 Cash Hao11 26 days ago in reply to Ankush

TI__Mastermind 46765 points

Then which demo project you are using for test? Have you tried with adc12_single_conversion_vref_internal demo?

0 Ankush 26 days ago in reply to Cash Hao11

Intellectual 500 points

yes I have tried adc12_single_conversion_vref_internal demo code

0 Cash Hao11 26 days ago in reply to Ankush

TI__Mastermind 46765 points

Ok. Let me run the test and give you feedback.

0 Ankush 26 days ago in reply to Cash Hao11

Intellectual 500 points

0 Ankush 24 days ago in reply to Cash Hao11

Intellectual 500 points

Hello Cash,
Just checking in to know if you had a chance to run the test. Please let me know your feedback whenever convenient.

0 Cash Hao11 24 days ago in reply to Ankush

TI__Mastermind 46765 points

Hi,

I run the adc12_single_conversion_vref_internal on the LP. Apply a 137mV on the PA25 pin. And record 10 times of the ADC results.

It seems that there are some noise in the data. That is majorly due to the SWD interfacing with the MCU. If the MCU runs at standalone mode, the noise level should be lower.

Best regards,

Cash Hao

0 Ankush 24 days ago in reply to Cash Hao11

Intellectual 500 points

Hello Cash,

I am using PB17 pin. Is there is any thing again, So i can solve the issue for ADC counts difference.

0 Cash Hao11 23 days ago in reply to Ankush

TI__Mastermind 46765 points

Hi,

There should be no difference between PA25 and PB17 on the LP.

Best regards,

Cash Hao

0 Ankush 23 days ago in reply to Cash Hao11

Intellectual 500 points

Hello Cash,

I am passing a 7 mV input signal to the ADC. Ideally, I should get around 15 ADC counts (or greater), but I am only seeing 1 count. If the input is less than 7 mV, the ADC always gives 0.

I tested the same setup on the MSP430 controller, and it works fine — even from 1 mV input it provides the expected ADC counts. Could you please help me understand why this behavior is different on the current controller, and how I can make it respond properly for such low-level inputs?

Looking forward to your support.

Best regards,
Ankush Tiwari