This repo contains the firmware for my dactyl keyboard, written in C using the Zephyr RTOS.
For the body I largely followed the instructions here.
Mistakes were made during the build. I had to resolder the order I'd connected the columns to the pins on the MCP23018, all of the diodes on the right side, and debug a short. Other than that, the build stage was relatively painless.
The firmware was a real learning curve. Initially I intended to use QMK, but my specific configuration was unsupported. I was faced with a decision to use a different soc, or build my firmware from scratch. So, naturally, I decided to write my own firmware.
I came across ZMK during my research, but again, my use case wasn't that well supported, so I started looking at tools I had used before like PlatformIO and Arduino. I didn't really want to use C++, and fancied using C, and then I stumbled upon Zephyr when looking through PlatformIO.
After getting my dev environment setup, I faced a steep learning curve. I broke down the task into chunks and plowed on. I've created a branch after each of these milestones to serve as a reminder to myself in the future.
blinky - something basic to compile and flash, just toggles the board led.
hello-world - communicating with uart over usb.
boop - make a single button work with gpio pins.
boop-rhs - make a single button work on the rhs using i2c.
lhs - complete scanning matrix on lhs.
matrix - complete scanning of rhs.
rhs-boop-2 - test using the PCF8575 as the rhs gpio extender
main - current version.
After experiencing a number of short issues on the rhs, I accidentally broke a pin of the MCP23018 when attempting to diagnose them. At that point, I elected to replace it with a different gpio expander, and instead opted for the PCF8575.
If your goal is just to make a keyboard, just use QMK or ZMK. However, if you wish to learn C, or Zephyr and really get to grips with how a keyboard works, then I can thoroughly recommend a project like this.
| Pin | Port/Pin | Usage |
|---|---|---|
| 0 | GPIO1_3 | Column 1 |
| 1 | GPIO1_2 | Column 2 |
| 2 | GPIO4_4 | Column 3 |
| 3 | GPIO4_5 | Column 4 |
| 4 | GPIO4_6 | Column 5 |
| 5 | GPIO4_8 | Column 6 |
| 6 | GPIO2_10 | Row 1 |
| 7 | GPIO2_17 | Row 2 |
| 8 | GPIO2_16 | Row 3 |
| 9 | GPIO2_11 | Row 4 |
| 10 | GPIO2_0 | Row 5 |
| 11 | GPIO2_2 | Row 6 |
| Pin | Usage | Notes |
|---|---|---|
| 18 | I2C1_SDA | to RHS |
| 19 | I2C1_SCL |
| Pin | Usage |
|---|---|
| 00 | Column 1 |
| 01 | Column 2 |
| 02 | Column 3 |
| 03 | Column 4 |
| 04 | Column 5 |
| 05 | Column 6 |
| 10 | Row 1 |
| 11 | Row 2 |
| 12 | Row 3 |
| 13 | Row 4 |
| 14 | Row 5 |
| 15 | Row 6 |