Raspberry Pi RP2040 Bare-Metal Programming – Day 2

The RP2040 documentation tells us that using the custom RP2040 MicroPython build along with the MicroPython SDK eliminates the need for the programmer to consult the registers area of the RP2040 data sheet. Since we are not coding with MicroPython or the MicroPython SDK we will depend on the RP2040 data sheet to guide us through bringing up one of the RP2040's UARTs. Not only will we breathe some firmware life into an RP2040 UART we will also code a buffered UART receive interrupt routine to support the UART hardware.