To the average microcontroller, Ethernet networks are quite a step up from the basic I2C, SPI and UART interfaces, requiring either a built-in Ethernet MAC or SPI-based MAC, with tedious ...
the Raspberry Pi 4 has six SPI controllers, six I2C controllers, and six UARTs – all on its 40-pin header. You can’t make use of all of these at once, but with up to four different connections ...