The key here is the "PIO" which you won't find on a Teensy. It lets you do extreme "bit banging" tricks including generating video. People have even implemented Ethernet on it. I've used it for some custom serial protocols ("Weigand") used by alarm panels.

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ge96 4 hours ago | parent [-]

Really I guess I don't know what that is then as I buy the Teensy since it has so much IO, multiple UART, multiple I2C busses, sd card reading, etc...

edit: interesting

(Teensy | Pico)

Special Features: CAN Bus (3x), SDIO, S/PDIF | PIO (Programmable I/O) (8 SMs)

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fortran77 an hour ago | parent [-]

The Pico PIO has an instruction set and can be programmed.

You write PIO assembly that runs autonomously on a state machine, with explicit timing (e.g., out, in, set, mov, jmp, wait) and cycle‑accurate interfaces. The CPU communicates via small FIFOs, and interrupts are optional; the PIO can be “fire‑and‑forget” for many protocols.

	▲	ge96 an hour ago \| parent [-]
		That's cool, I'm not at that level right now, side note I bought an FPGA like 5 years ago and still haven't used it.