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Multi-channel RS422 Interface


This isn’t strictly RS422 but it’s close… RS422 defines two signals, each swinging from 0V to 5V and one signal is an inverted version of the other.


The differential interface capability of GPIO 1 is ideal for this, however this interface is limited to 3.3V so not quite so ideal. However the GPIO3 interface is 5V and therefore capable of providing a two-wire differential driver similar to RS422.


Using external drivers / receivers tranceivers etc. this becomes even easier. The FPGA can provide several UART functions or the serial RXD/TXD port of the Pi could be used…