mirror of
https://github.com/qmk/qmk_firmware
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182 lines
6.4 KiB
Markdown
182 lines
6.4 KiB
Markdown
Let's Split
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======
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This readme and most of the code are from https://github.com/ahtn/tmk_keyboard/
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Split keyboard firmware for Arduino Pro Micro or other ATmega32u4
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based boards.
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## Build Guide
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A build guide for putting together the Let's Split v2 can be found here: [An Overly Verbose Guide to Building a Let's Split Keyboard](https://github.com/nicinabox/lets-split-guide)
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There is additional information there about flashing and adding RGB underglow.
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## First Time Setup
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Download or clone the whole firmware and navigate to the keyboards/lets_split directory. Once your dev env is setup, you'll be able to generate the default .hex using:
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```
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$ make rev2
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```
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You will see a lot of output and if everything worked correctly you will see the built hex files:
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```
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lets_split_rev2_serial.hex
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lets_split_rev2_i2c.hex
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```
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If you would like to use one of the alternative keymaps, or create your own, copy one of the existing [keymaps](keymaps/) and run make like so:
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```
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$ make rev2-YOUR_KEYMAP_NAME
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```
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If everything worked correctly you will see a file:
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```
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lets_split_rev2_YOUR_KEYMAP_NAME.hex
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```
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For more information on customizing keymaps, take a look at the primary documentation for [Customizing Your Keymap](/readme.md##customizing-your-keymap) in the main readme.md.
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### Let's split 1.0
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If you have a first generation Let's Split you will need to use the revision 1 code. To do so, use `rev1` in all your commands instead.
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Features
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--------
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For the full Quantum Mechanical Keyboard feature list, see [the parent readme.md](/readme.md).
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Some features supported by the firmware:
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* Either half can connect to the computer via USB, or both halves can be used
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independently.
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* You only need 3 wires to connect the two halves. Two for VCC and GND and one
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for serial communication.
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* Optional support for I2C connection between the two halves if for some
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reason you require a faster connection between the two halves. Note this
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requires an extra wire between halves and pull-up resistors on the data lines.
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Required Hardware
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-----------------
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Apart from diodes and key switches for the keyboard matrix in each half, you
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will need:
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* 2 Arduino Pro Micro's. You can find theses on aliexpress for ≈3.50USD each.
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* 2 TRRS sockets and 1 TRRS cable, or 2 TRS sockets and 1 TRS cable
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Alternatively, you can use any sort of cable and socket that has at least 3
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wires. If you want to use I2C to communicate between halves, you will need a
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cable with at least 4 wires and 2x 4.7kΩ pull-up resistors
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Optional Hardware
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-----------------
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A speaker can be hooked-up to either side to the `5` (`C6`) pin and `GND`, and turned on via `AUDIO_ENABLE`.
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Wiring
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------
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The 3 wires of the TRS/TRRS cable need to connect GND, VCC, and digital pin 3 (i.e.
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PD0 on the ATmega32u4) between the two Pro Micros.
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Then wire your key matrix to any of the remaining 17 IO pins of the pro micro
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and modify the `matrix.c` accordingly.
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The wiring for serial:
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The wiring for i2c:
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The pull-up resistors may be placed on either half. It is also possible
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to use 4 resistors and have the pull-ups in both halves, but this is
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unnecessary in simple use cases.
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Notes on Software Configuration
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-------------------------------
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Configuring the firmware is similar to any other QMK project. One thing
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to note is that `MATIX_ROWS` in `config.h` is the total number of rows between
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the two halves, i.e. if your split keyboard has 4 rows in each half, then
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`MATRIX_ROWS=8`.
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Also the current implementation assumes a maximum of 8 columns, but it would
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not be very difficult to adapt it to support more if required.
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Flashing
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-------
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From the keymap directory run `make SUBPROJECT-KEYMAP-avrdude` for automatic serial port resolution and flashing.
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Example: `make rev2-serial-avrdude`
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Choosing which board to plug the USB cable into (choosing Master)
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--------
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Because the two boards are identical, the firmware has logic to differentiate the left and right board.
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It uses two strategies to figure things out: look at the EEPROM (memory on the chip) or looks if the current board has the usb cable.
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The EEPROM approach requires additional setup (flashing the eeeprom) but allows you to swap the usb cable to either side.
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The USB cable approach is easier to setup and if you just want the usb cable on the left board, you do not need to do anything extra.
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### Setting the left hand as master
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If you always plug the usb cable into the left board, nothing extra is needed as this is the default. Comment out `EE_HANDS` and comment out `I2C_MASTER_RIGHT` or `MASTER_RIGHT` if for some reason it was set.
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### Setting the right hand as master
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If you always plug the usb cable into the right board, add an extra flag to your `config.h`
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```
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#define MASTER_RIGHT
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```
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### Setting EE_hands to use either hands as master
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If you define `EE_HANDS` in your `config.h`, you will need to set the
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EEPROM for the left and right halves.
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The EEPROM is used to store whether the
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half is left handed or right handed. This makes it so that the same firmware
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file will run on both hands instead of having to flash left and right handed
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versions of the firmware to each half. To flash the EEPROM file for the left
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half run:
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```
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avrdude -p atmega32u4 -P $(COM_PORT) -c avr109 -U eeprom:w:eeprom-lefthand.eep
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// or the equivalent in dfu-programmer
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```
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and similarly for right half
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```
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avrdude -p atmega32u4 -P $(COM_PORT) -c avr109 -U eeprom:w:eeprom-righhand.eep
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// or the equivalent in dfu-programmer
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```
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NOTE: replace `$(COM_PORT)` with the port of your device (e.g. `/dev/ttyACM0`)
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After you have flashed the EEPROM, you then need to set `EE_HANDS` in your config.h, rebuild the hex files and reflash.
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Note that you need to program both halves, but you have the option of using
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different keymaps for each half. You could program the left half with a QWERTY
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layout and the right half with a Colemak layout using bootmagic's default layout option.
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Then if you connect the left half to a computer by USB the keyboard will use QWERTY and Colemak when the
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right half is connected.
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Notes on Using Pro Micro 3.3V
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-----------------------------
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Do update the `F_CPU` parameter in `rules.mk` to `8000000` which reflects
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the frequency on the 3.3V board.
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Also, if the slave board is producing weird characters in certain columns,
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update the following line in `matrix.c` to the following:
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```
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// _delay_us(30); // without this wait read unstable value.
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_delay_us(300); // without this wait read unstable value.
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```
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