[Cixelyn]

Yeah! Docs start on page 323 here: https://datasheets.raspberrypi.org/rp2040/rp2040_datasheet.p....

Looks like there's an assembler for programming the PIO peripheral; they seem quite capable with two IO registers and two scratch registers.

I've used a similar sort of embedded state machine inside EFM8 microcontrollers before. They're great not just for implementing custom communication protocols, but also for offloading simple tasks: one example I've coded before is that you can offload software key debouncing to the state machine, and even get an interrupt on keypress. This greatly simplifies the main loop as you don't need to dedicate polling time or write debounce calculations!

[synack]

TI's PRU is a similar concept, but the PIO here is simpler. Parallax Propeller also has a similar flavor with lots of small cores doing different things. It's not a new idea, but the PIO looks like a nice balance between capability and complexity.

I'm in love with this documentation. It's not just prettier than other vendors' datasheets, it's also got lots of examples, links, tips, and explanations about the "why" in addition to the "how"