ADS1261EVM: ADC showing only half of the expected ADC Value

Paul Will-Groo

Part Number: ADS1261EVM

Hello,

I have trouble getting the right ADC value from the ADS1261EVM Evaluation board. Currently, I am using the +/- 2,5 V analog supply.

For the configuration of the registers I am using the Delta-Sigma ADC EvaluaTIon Software with the following values:

Mostly, I am using default values. I changed the REFENB to the internal reference (REG 0x06 VAL 0x15) , and the Input to AN1 and AIN0 ((REG 0x11 VAL 0x21). I apllied a Voltage of 0,5 V to those pins.

Now what happens: I always get a value of 0,25 V out of the measurement, but I cannot see what the problem is.

Thanks you in advance

over 4 years ago

+1 Paul Will-Groo over 4 years ago

Prodigy 30 points

I guess I found my Issue myself,

it isn't enough only to enable the internal reference. You have to set your upper and lower boundaries yourself in the REF Register. With that I get the right value.

0 Bryan Lizon86 over 4 years ago in reply to Paul Will-Groo

TI__Guru 58961 points

Hi Paul,

Glad you quickly identified the issue, and let us know that you did.

If you have any additional questions, feel free to start a new thread and we will answer them there.

-Bryan

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ADS1261EVM: ADC showing only half of the expected ADC Value