This may look like a joyless ripoff of @adafruit's Feather M0 Basic, but I assure you it's not. I redid the pinout entirely to break out as much of the L21's functionality as possible while making it feel familiar: DACs on A0 and A1, all the opamp pins on the analog row, and the L21's special battery backup input on the "free" pin on the bottom. I also reserved pins for an eventual Neopixel and Flash chip; to quote the 'fruit, this board is the “bones” for building future SAM L21 based gadgets.
Had to rework the USB port a lot, as one does, but y’all: that is a bootloader.
also I think the amount of rosin fumes I just inhaled have taken a year off my life.
Welp. I’ve only coded the UI so far, and even then I’m unsure why the top two rows of pixels are glitchy. But the new Feather works, so I guess I’d better start writing the @hackaday project page! #opampchallenge
For background: the SAM L21 microcontroller that I’ve chosen for its low power prowess? It also has an advanced analog peripheral with three op amps, right there on the chip! We can program how they’re connected to each other right there in the code, and this UI lets us hook them up however we please. Inspired by David Johnson Davies’ Pocket Op Amp Lab, I’m calling this the Feather Op Amp Lab. (but of course it’s not real yet; I still have some code to write to make it do stuff)
stress testing the UI. This actually conveys a lot of information in 128x30 pixels! Tho I’ll need those top two rows for some of the more esoteric ways OA2 can connect back to OA0 and OA1. (these circuits aren’t meant to make any sense btw, it’s just me pressing buttons)
milling a board to break out the op amp pins. i am very good at documenting things.
