ADS131A02: Repeated Sample Values when Reading out from ADC

Ajith Peter

Part Number: ADS131A02

Hello,

I am running my ADS131A02 ADC using a 16MHz crystal. The sampling rate is set to 20kHz. I am reading the ADC through an SPI read at the rising edge of every DRDY pulse. I am getting 20000 samples in a second, but if I look at the received data buffer, two successive sample values in the register are the same.

I checked the entire code on my DSP side and I feel that the problem is rising from the ADC side ? Any ideas why two successive reads will yield the same sample values ?

Any help will be deeply appreciated.

Thanks and regards

Ajith

over 6 years ago

0 Joseph Wu over 6 years ago

TI__Guru* 98025 points

Ajith,

Not that this is the direct cause of the problem, but generally, the data should be read at the falling edge of the /DRDY pulse.

I'm guessing that you somehow are reading the data too early, but I need much more information. The communications on this device are rather difficult and I'll need to know about the communication modes you're using. What are the settings of the M0, M1, and M2 pins?

After that what are you sending and what sequence are you sending it? It would help to see the output of a logic analyzer to verify the data and timing of the communications. If you have the output, you can post plots into this thread.

Again, there are many communication options for this device and it'll be important to see what's coming out of the device.

Joseph Wu

0 Ajith Peter over 6 years ago in reply to Joseph Wu

Prodigy 50 points

Dear Joseph,

I owe you a beer !!! You rock !!! :) It was the falling edge !

Thanks a zillion !

Best Regards

Ajith

Data converters

Data converters forum

ADS131A02: Repeated Sample Values when Reading out from ADC