How to Initialize and Interact with Programmable I/O

So far, we’ve studied the Assembly Language instructions for the ARM Cortex-M0+ processor. In this chapter, we put that aside and look at a new Assembly Language syntax quite different from ARM’s. The RP2040 contains eight programmable I/O (PIO) processors that are programmed as state machines with their own Assembly Language instructions. There is a tool in the SDK, pioasm, which assembles these in a similar manner to the GNU Assembler we have used.