ISOW7841EVM: Not able to establish SPI communication with ISOW7841EVM

Hi Rohan,

Thanks for reaching out and sorry to hear about the issue.

Rohan Mane said:

When we connect ISOW7841EVM GND1 and GND2 then SPI communication works properly.

It is very unusual to hear that SPI communication issue disappears when GND1 and GND2 are shorted. This indicates that there isn't any software timing issue or issue due to added propagation delay of ISOW7841.

Could you please elaborate on the SPI communication issue a little more?
I am assuming you are either trying to send data from STM to DAC or trying to read data from DAC to STM. Could you quantify how exactly you are seeing an issue here? Does STM fail to establish communication at all or do you see data received is corrupted?
Are you doing any of EMC tests this test setup or is it just being tested in the lab environment?

Any more details related to the above questions will help us understand the issue and try debug. Thanks.

Regards,
Koteshwar Rao

Hi Rohan,

I would also like to request you to share some waveforms where signals on the MCU side of isolator and signals from the DAC side of isolator are captured in the same waveform. Capture the waveform such that left side and right side waveforms of the isolator do not match so that I can review and comment if the isolator is indeed not working correctly.

I ask these waveform because the ISOW7841 is a physical layer device and this is the only place where it can make an impact. Thanks.

Regards,
Koteshwar Rao