| SN32F268 | ATmega32U4 | AT90USB1286 | Proton C - STM32F303xC | Blackpill - STM32F411 | Nice Nano (nRF52840) | RP2040 | |
|---|---|---|---|---|---|---|---|
| Speed | 48MHz | 16MHz | 16MHz | 72MHz | ~96MHz | 64MHz | 2@ 133MHz |
| Voltage | 3.3V | 5V | 5V | 3.3V with some 5V capable pins | 3.3V with 5V capable pins | 3.3v | 3.3v |
| Flash size | 32kB (~28kB usable) | 32kB (28kB usable) | 128kB (120kB usable) | 256kB | 512kB | 1MB | off-chip flash, up to 16MB |
| EEPROM size | Emulated | 1kB | 4kB | Emulated | Emulated (with SPI SOIC footprint) | Emulated | Emulated |
| Memory | 2kB | 2.5kB | 8kB | 48kB | 128kB | 256 kB | 264kB |
| Timers | 2 total | 4 total | 4 total | 10 total | 11 total | 8 | 9 total |
| Digital IO | "up to 42" pins | 25 pins | 46 pins | 37 pins | 26 usable pins (more with caveats) | 21 | 30 |
| Architecture | ARM Cortex M0 | AVR8 8-bit | AVR8 8-bit | ARM Cortex M4 | ARM Cortex M4 | ARM Cortex M4 | ARM Cortex M0+ |
| Cost | N/A | ~$6 - Digikey | ~$12 - Digikey | ~$8 - Digikey | ~$11 - Digikey ~$5 -AliExpress |
~$8 - Digikey ~$25 NiceNano |
$1 - Digikey $9 Adafruit KB2040 |
- Emulated eeprom uses program flash as EEPROM, reducing the total flash size.
- All controllers support external eeprom, via I2C or SPI.
- RP2040 has 2 cores, but QMK will not leverage the second one, currently.
- Prices are relative, and fluctuate