There are several other considerations for writing on the SPI:
- The R/W bit must be set to 0.
- The data on SDI pin is clocked into a shift register on each rising edge on the SCK pin.
- The CS# must be held low for data to be clocked. Device will ignore clock pulses if CS# is held high.
- The CS# transition from high to low must occur when SCK is low.
- When SCK and SDI lines are shared between devices, TI recommends to hold the CS# line high on the device that is not to be clocked.
There are several other considerations for SPI readback:
- The R/W bit must be set to 1.
- The MUXOUT pin will always be low for the address portion of the transaction.
- The data on MUXOUT becomes available momentarily after the falling edge of SCK, and therefore, should be read back on the rising edge of SCK.
- The data portion of the transition on the SDI line is always ignored.