qmk_firmware/keyboards/handwired/dactyl_promicro/readme.md

# Dactyl with Arduino Pro Micro

See https://github.com/adereth/dactyl-keyboard for the original Version.

This Dactyl uses the Arduino Pro Mirco (2x).
Wiring is a 6x6 Matrix like the [Dactyl Manuform](https://github.com/qmk/qmk_firmware/tree/master/keyboards/handwired/dactyl_manuform)


## Build the Firmware:

  - Build the firmware with `make handwired/dactyl_promicro:<keymapname>`, for example `make handwired/dactyl:default`
  - This will result in a hex file called `handwired_dactyl_promicro_<keymapname>.hex`, e.g.
    `handwired_dactyl_promicro_default.hex`

How to setup your build enviroment can be found here: [Installing Build Tools](https://docs.qmk.fm/#/getting_started_build_tools)

## Required Hardware

Apart from diodes and key switches for the keyboard matrix in each half, you
will need:

* 2 Arduino Pro Micros. You can find these on AliExpress for ≈3.50USD each.
* 2 TRRS sockets and 1 TRRS cable, or 2 TRS sockets and 1 TRS cable

Alternatively, you can use any sort of cable and socket that has at least 3
wires. If you want to use I2C to communicate between halves, you will need a
cable with at least 4 wires and 2x 4.7kΩ pull-up resistors

## Optional Hardware
A speaker can be hooked-up to either side to the `5` (`C6`) pin and `GND`, and turned on via `AUDIO_ENABLE`.

## Wiring

The 3 wires of the TRS/TRRS cable need to connect GND, VCC, and digital pin 3 (i.e.
PD0 on the ATmega32u4) between the two Pro Micros.

Next, wire your key matrix to any of the remaining 17 IO pins of the pro micro
and modify the `matrix.c` accordingly.

The wiring for serial:

![serial wiring](https://i.imgur.com/C3D1GAQ.png)

The wiring for i2c:

![i2c wiring](https://i.imgur.com/Hbzhc6E.png)

The pull-up resistors may be placed on either half. It is also possible
to use 4 resistors and have the pull-ups in both halves, but this is
unnecessary in simple use cases.

You can change your configuration between serial and i2c by modifying your `config.h` file.

## Notes on Software Configuration

the keymaps in here are for the 4x5 layout of the keyboard only.

## Flashing

To flash your firmware take a look at: [Flashing Instructions and Bootloader Information](https://docs.qmk.fm/#/flashing).

Under Windows the most convenient way is installing the [QMK Drivers](https://github.com/qmk/qmk_driver_installer/releases) and use the [QMK Toolbox](https://github.com/qmk/qmk_toolbox/releases).


## Choosing which board to plug the USB cable into (choosing Master)

### Setting the right or left hand as master

If you always plug the usb cable into the right board, add an extra flag to your `config.h`
```
 #define MASTER_RIGHT
```

OR

```
 #define MASTER_LEFT
```


Notes on Using Pro Micro 3.3V
-----------------------------

Do update the `F_CPU` parameter in `rules.mk` to `8000000` which reflects
the frequency on the 3.3V board.

Also, if the slave board is producing weird characters in certain columns,
update the following line in `matrix.c` to the following:

```
// _delay_us(30);  // without this wait read unstable value.
_delay_us(300);  // without this wait read unstable value.
```