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ADS1256: ADS1256

Igal Sokolov
Prodigy 100 points
Part Number: ADS1256
Other Parts Discussed in Thread: ADS131A02

Hello,

I am researching the most efficient (time-wise) way to transfer the data from ADC to ARM CPU that runs Linux. Is there any way to initialize ADC's SPI in master-mode ?

Thank you,

Igal

  • 0
    TI__Mastermind 44680 points

    Hi Igal,

    The ADS1256's SPI only behaves as a slave device.

    For the fastest data transfer, I would recommend using the maximum SCLK frequency (up to 1/4 fCLK frequency), using the /DRDY interrupt signal to trigger reading data, and using the MUX cycling procedure (shown in Figure 19 of the datasheet) if multiplexing through multiple channels.

    Best regards,
    Chris

  • 0 in reply to Christopher Hall
    Prodigy 100 points

    Thank you Chris for the prompt and informative answer.

    Are you aware of other 24-bit ADCs that can be initialized as SPI master ? How to find out that from the data sheets ?

    Is that even worth to go to that direction ?

    Thank you,

    Igal Sokolov

  • 0 in reply to Igal Sokolov
    TI__Mastermind 44680 points
    Hi Igal,

    There aren't many devices that provide an SPI master mode, but one that does is the ADS131A02. It's not always easy to tell without searching through the datasheet.

    I'm not sure that an SPI master mode device would provide much more throughput than an SPI slave. (The ADS131A02 has a higher data rate than the ADS1256, so for that reason alone you'll be able to have a faster throughput). The benefit of a SPI slave would be that your CPU can schedule when to read data (as long as it is read with before the next ADC conversion completes). Using the ADC in master mode may require you to make the read data task a high priority.

    Best regards,
    Chris