I'm trying to use SC16IS740 as a bridge from SPI to UART, but I'm yet to receive a response from the device as shown in datasheet page 43. There is a stable 3.072 MHz crystal clock visible on the oscilloscope as well.
I've provided an example below. It shows what happens when 10001000 is sent as the first byte (R/W = 1, A=0001, CH1=0, CH2=0, X=0). 0xFF is sent as dummy data to provide clock cycles for the next byte expecting to read a value (all cleared due to reset)
- Part of schematic showing how connections are done
- Oscilloscope output for SI
- Oscilloscope output for CS
- Oscilloscope output for SO
Excuse if I mistakenly published in the wrong "place". I am unfamiliar with NXP communities forum structure.