The Frood is a high-performance and affordable Pro Micro drop-in replacement based on a Raspberry Pi RP2040. It is physically and electrically compatible with Elite-C/nice!nano as much as possible.
It follows the SparkFun Pro Micro RP2040 pinout with 5 more pins (GPIO12-GPIO16) added along the bottom edge (like on Elite-C), and USB data lines broken out in the top corners.
- Powerful dual-core Raspberry Pi RP2040 MCU
- 4 MB of on-board flash memory
- Only 3.2 mm thick thanks to a mid-mounted USB-C socket
- 500 mA linear regulator and resettable fuse
- Combined Pro Micro / Elite-C / nice!nano / SparkFun Pro Micro RP2040 compatible pinout
- 5 more I/O pins (GPIO12-GPIO16) added along the bottom edge
- 2 more I/O pins (GPIO10, GPIO11) can be converted from left-hand side GND pins by cutting a jumper
- 23-25 total available digital pins for a maximum of 11x12 = 132 (or even 12x13 = 156) switches
- 4 pins configurable as analogue inputs
- USB D+/D- broken out for use with an external USB socket/daughterboard
- USB power sensing on GPIO19 for split keyboard side detection
- UF2 bootloader for drag & drop programming with no extra software required
- Orange indicator LED on pin GPIO17
- Now with official CircuitPython support
The Frood is available from 42keebs.eu.
Rev9 (03/01/2024)
- Allows converting left-hand side GND pins into GPIO pins (GPIO10, GPIO11) by cutting PCB jumpers
- VBUS IN/OUT solder jumper dropped, the RAW pin is now connected to VBUS after a Schottky diode/input of linear regulator before a resettable fuse
- Uses a different (but equivalent) USB-C socket due to component shortage
- Routing and silkscreen tweaks/improvements
Rev8 (10/10/2023)
- Add a 2-way solder jumper to select VBUS OUT or VBUS IN on the RAW pin
- Use orange indicator LED again
Rev7 (23/06/2023)
- Use a different 4 MB flash chip (Winbond W25Q32JVUUIQ) which will hopefully not need a special config
- Use a higher-quality Panasonic reset/boot switches
- Some routing tweaks
- Bug: uses red indicator LED by mistake
Rev6 (28/12/2022)
- Use a 4 MB (32 Mbit) flash chip (needs a special configuration in QMK
config.h:#define RP2040_FLASH_GD25Q64CS) - Tweak a few tracks
Rev5 (26/10/2022)
- Improve USB socket position to match nice!nano
- Add BOOT/RESET pads on the bottom of the PCB (when the buttons are not accessible)
- Use a smaller crystal to gain some valuable space
- Add an orange indicator LED on pin GPIO17 (inspired by the 0xB2)
Rev4 (28/09/2022) - Confirmed working
- Use a 2 MB flash with correct supply voltage rating
- Switch to GT-USB-7014C USB-C socket and a standard 1.6 mm PCB
- Improve pin labels
- Improve routing
Rev3 (18/08/2022) - DO NOT USE!
- Rename to "Frood"
- Use HRO-TYPE-C-31-M-14 for a fully mid-mounted socket with a 1.0 mm PCB
- Use 500 mA fuse instead of 350 mA one
- Improve layout (move USB termination resistors closer to MCU)
- Still uses the same flash chip with an incorrect supply voltage (1.8-2.6 V)
Rev2 (16/08/2022) - DO NOT USE!
- Rename to "PiMicro2040"
- Fix crystal routing
- Use Elite-C/nice!nano-like outline
- Use mid-mounted USB-C connector (HRO-TYPE-C-31-M-13)
- Use a "standard" Sparkfun Pro Micro-compatible pinout
- Add 350 mA resettable fuse
- Add VBUS sensing
- Break-out USB data lines
- Contains a critical error - flash chip with an incorrect supply voltage (1.8-2.6 V)
Rev1 (08/08/2022) - DO NOT USE!
- Initial version with a top-mounted USB-C socket, a shorter outline and a custom pinout
- Contains a critial error - incorrect crystal routing due to a mismatch between a 2-pin symbol and a 4-pin footprint