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ADS1299: Robust RESET via SPI when status is unknown

yf liu
Prodigy 100 points
Part Number: ADS1299

Hi,

From the data sheet, we can read that the ADS1299 might be in status like: POWER-DOWN, STANDBY, NOT-STARTED, STARTED, CONTINUOUS/SINGLE-SHOT etc.

On a device where the START/CLKSEL/PWDN/RESET pins have been statically provisioned so that MCU can rely on SPI commands to control the ADS. Given the fact the MCU might have been rebooted while the ADS device is still running. There is a need for MCU to robustly RESET ads1299 device via SPI commands despite current status of the ADS. 

I am currently considering the following command sequences:

  1. WAKEUP just in case device is in STANDBY state
  2. RESET 

Is the above sequence enough? 

Regards,

yf

  

  • 0
    TI__Guru**** 180931 points
    Hi yf,

    Do you have any extra GPIO's on your processor? I'm not sure what might be going on with your setup with the ADS1299 (schematics and screen captures would help), but having access to the RESET pin could help in situations where the SPI communications are corrupted for whatever reason - reboot of the MCU for instance.
  • 0 in reply to Tom Hendrick
    Prodigy 100 points

    Tom,

    attached you can find my schematics. 

    Regards,

    yf

  • 0 in reply to yf liu
    TI__Guru 55152 points
    Hello yf,

    I agree with Tom that having direct access to the RESET pin is a preferable method since issuing the commands relies on SPI communication being uncorrupted. If you are able to connect S3 to GND to pull the pin low it would be a more dependable design.

    If everything is running smoothly then issuing WAKEUP & RESET via SPI will be enough, but if there is an issue in the transmission line then the results cannot be guaranteed.