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ADS127L01: Is RDATA cmd needed to read conversion data from ADC when working in SPI mode and using DRDY signal?

Wojtek Jodlowski
Prodigy 30 points
Part Number: ADS127L01

After analyzing datasheet I have impression that I can read conversion data from ADS127L01 ADC without using RDATA command: conversion results are loaded into the output shift register before DRDY signal goes low so I think that generating SPI frame with CS low and 24 clks (or 32 clks if status word included) of SCLK signal will shift this result out to the DOUT pin. So there is no need to *** RDATA cmd to DIN pin before getting conversion result. Am I correct? Please clarify this to me.

Regards

Wojtek

  • 0
    TI__Guru 57296 points

    Hello Wojtek,

    Thank you for your post and welcome to our forum.

    You are correct that data is automatically loaded into the output shift register before the /DRDY interrupt occurs. This data can be read simply by applying SCLKs with 0x00 or NULL on the DIN pin. To reread the most recent conversion, send the RDATA command to reload the conversion result into the output shift register and send the number of required SCLKs again. This must be completed before the next /DRDY occurs to avoid reading a mix of old and new data, which would corrupt the result.

    Regards,