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ADS131A02: Good way to send the reset command even if the communication mode is unknown

Genius 15690 points
Part Number: ADS131A02
Other Parts Discussed in Thread: ADS131A04

Hello,

I have a question for ADS131A02.

ADS131A02 SPI has two different modes which are Fixed-Frame mode and Dynamic Frame mode.
Usually the host MCU knows which mode ADS131A02 is in because the MCU controls the mode.
But if the MCU goes out of control because of noise or S/W bugs etc,  the MCU don’t know what mode the ADS131A02 is.
In that case, MCU don’t know which mode it should use for the SPI communication.

So the question is that is there any good way to send reset command correctly to ADS131A02 even if the MCU doesn’t know which mode ADS131A02 is?

Regards,
Oba

  • Oba,


    Normally, I think that the best way to do the RESET is to use the RESET pin instead of the reset command. However, if you don't have access to the pin, I think there is an alternative, even if you don't know if the device is in fixed-frame mode or dynamic frame mode.

    I would send the command as if the device is in fixed-frame mode. In that mode, you would clock out the command with the total number of words for that transaction (6 words for the ADS131A04 and 4 words for the ADS131A02). The ADS131A0x device is specific about the communication transaction and underclocking the data (not giving enough SCLKs for the transaction) may cause it to not accept the command. However, I don't believe there is a consequence of overclocking the data (sending too many SCLKs for the command).

    Hopefully that works for you. If you are having problems with the MCU, I would ensure that the controller is stable first. Regardless, I think treating the device as if it were in the fixed-frame mode should work.


    Joseph Wu