EVM430-FR6043: Difficulty reading ADC values

Pierre Gambier

Hello,

I am currently working on an EVM430-FR6043 card. I'm trying to get an external analog signal through an ADC on the MCU. I enter my signal on PIN 32 which is the analog input A3 (I unsoldered the led that was on this PIN). My problem is that the signal does not seem to vary, I always get the same value which is 74. Checking with the voltmeter I have the right analogical value in input which value changes over time.
I initialize my registers in the following way:

And in a while loop I get the value and start a new capture

Do you have any idea how to make this work?

Best regards,

Pierre

over 3 years ago

0 Johnson He over 3 years ago

TI__Mastermind 30386 points

Hi Pierre,

Does your code is modified based this example?

https://dev.ti.com/tirex/explore/node?node=A__AC2i1bGmQkBkBbBZ2lwHbg__msp430ware__IOGqZri__LATEST

And have you tried other channel?

Thanks!

Best Regards

Johnson

0 Pierre Gambier over 3 years ago in reply to Johnson He

Prodigy 60 points

Hi Johnson,

My code is not based on this one but I tried the same initializations for A3 and it doesn't seem to solve my problem. The only thing that changes is the output value of the ADC which becomes 1857 but remains constant

I don't think I can try other channels as I'm on an evaluation card they are already in use.

Thanks for helping

Pierre

0 Bruce McKenney over 3 years ago in reply to Pierre Gambier

Guru 101935 points

> ADC12CTL1 |= ADC12SHP_0;

I recommend you set SHP=1 to get the pulse mode. Try instead:

> ADC12CTL1 |= ADC12SHP_1;

0 Pierre Gambier over 3 years ago in reply to Bruce McKenney

Prodigy 60 points

Hello Bruce,

I tried your idea but when running I get caught in the following interrupt :

The program stops at the green line. This code is located in a file named is_trap.asm which is added when compiling with ccs studio i guess.

Thanks for helping

Pierre

+1 Bruce McKenney over 3 years ago in reply to Pierre Gambier

Guru 101935 points

Your code is enabling ADC12IE0, but I don't see an ISR (ADC12_B_VECTOR) for it. If you didn't have one, that would be the symptom.

If you're not interested in the interrupt, don't enable IE0. (You can instead spin for completion using something like "while(ADC12CTL1 & ADC12BUSY);" -- it will be pretty quick.)

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EVM430-FR6043: Difficulty reading ADC values