Hello,

I have found an issue in duplication mode of SPI expander. It occurs in situation when master wants to duplicate output data to multiple slaves. If slaves use adjacent channels like SS3 and SS4 and master decides to activate them simultaneously the first slave (SS3) is activated by SS signal one period of SCK signal prior the another slave (SS4). It means that the first slave gets first byte shifted by one pulse of SCK prior the second slave.

Here is the correct function of expander. One master transmits to one slave.

Here is incorrect function of expander. One master transmits to two adjacent slaves. The slave select signal for the slaves is not aligned ant the first slave catches a misaligned data on MOSI signal.

The solution is not to place same slaves side by side to each other.