Good day,
We are trying to interface TCAN4550 to nRF52840 over SPI, and found that sometimes TCAN throws SPI error (underflow of read/write).
Looking further, we found that this always happens after MOSI having a glitch between nCS low and first SCK rising edge:
On that figure, glitch in one of the previous transactions took place so the error (0x88 on MISO, 1st byte) is already here. But the idea is the same.
Theoretically, this should not affect communication, since the glitch is in between nCS/SCK, and there is no timing violations either.
However, somehow that glitch affects TCAN, making it think that not the right amount of data was sent/read.
While we are working with TI to clarify that, question to Nordic team: how to get rid of that glitch on MOSI?
I tried to manually configure the driver, clear MOSI line prior to transaction, use pull-down config... same thing.. sometimes we do see that pulse.
SPI config: 2MHz (tried lower speed - same thing), manual CS control, Mode 0, all SPI pins - high-frequency / standard drive (tried H0H1 too).
Thanks! Wishing everyone success in development!
