Other Parts Discussed in Thread: ADS8694,
My ADS8694 is not responding on SPI, similiar to this question: ADS8698: the ADC does not response - Data converters forum - Data converters - TI E2E support forums
The platform is Raspberry PI 4, and on this platform, the SPI writes are per byte, and the clock stretches in between the bytes, as shown in the linked topic. I have spent a lot of time searching for a SPI fix on the Raspberry Pi, but there seems to be none.
My question is, is there such a timing requirement on SCLK that there cannot be a clock pulse stretched?
Unfortunately that detail information is not in the datasheet, so it would require someone to look at the design HDL code to see if such a constraint exists, or perhaps setup an eval board with a Raspberry Pi to at least confirm the issue exists - I could send some code over to help with that. Or perhaps this is already known...?
Its possible that something else is wrong in my setup. I have tried different SPI bus speeds to no avail. I have tried every combination of clock polarity and phase. The ADS8698 simply does not respond - exactly as shown in the related topic. I notice that on power up, the reference voltage (REFSEL is GND) is not present, but I read that the ADC is in power down until a SPI transaction wakes it up. I have been sending it 0xA000. There is no echo back of any SPI command that I write.
