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diff --git a/keyboards/lets_splitv2/readme.md b/keyboards/lets_splitv2/readme.md new file mode 100644 index 0000000000..73fdb0f789 --- /dev/null +++ b/keyboards/lets_splitv2/readme.md @@ -0,0 +1,102 @@ +Let's Split +====== + +This readme and most of the code are from https://github.com/ahtn/tmk_keyboard/ + +Split keyboard firmware for Arduino Pro Micro or other ATmega32u4 +based boards. + +Features +-------- + +Some features supported by the firmware: + +* Either half can connect to the computer via USB, or both halves can be used + independently. +* You only need 3 wires to connect the two halves. Two for VCC and GND and one + for serial communication. +* Optional support for I2C connection between the two halves if for some + reason you require a faster connection between the two halves. Note this + requires an extra wire between halves and pull-up resistors on the data lines. + +Required Hardware +----------------- + +Apart from diodes and key switches for the keyboard matrix in each half, you +will need: + +* 2 Arduino Pro Micro's. You can find theses on aliexpress for ≈3.50USD each. +* 2 TRS sockets +* 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 cable need to connect GND, VCC, and digital pin 3 (i.e. +PD0 on the ATmega32u4) between the two Pro Micros. + +Then 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](imgs/split-keyboard-serial-schematic.png) + +The wiring for i2c: + +![i2c wiring](imgs/split-keyboard-i2c-schematic.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. + +Notes on Software Configuration +------------------------------- + +Configuring the firmware is similar to any other TMK project. One thing +to note is that `MATIX_ROWS` in `config.h` is the total number of rows between +the two halves, i.e. if your split keyboard has 4 rows in each half, then +`MATRIX_ROWS=8`. + +Also the current implementation assumes a maximum of 8 columns, but it would +not be very difficult to adapt it to support more if required. + + +Flashing +-------- + +If you define `EE_HANDS` in your `config.h`, you will need to set the +EEPROM for the left and right halves. The EEPROM is used to store whether the +half is left handed or right handed. This makes it so that the same firmware +file will run on both hands instead of having to flash left and right handed +versions of the firmware to each half. To flash the EEPROM file for the left +half run: +``` +make eeprom-left +``` +and similarly for right half +``` +make eeprom-right +``` + +After you have flashed the EEPROM for the first time, you then need to program +the flash memory: +``` +make program +``` +Note that you need to program both halves, but you have the option of using +different keymaps for each half. You could program the left half with a QWERTY +layout and the right half with a Colemak layout. Then if you connect the left +half to a computer by USB the keyboard will use QWERTY and Colemak when the +right half is connected. + + |