qmk_firmware/docs/feature_console_in.md
2017-12-28 18:35:04 -05:00

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# Console In
The "Console" in QMK refers to PJRC's vendor page of `0xFF31` and usage page of `0x74` - this is mainly used for sending debug statements to the computer that can be read via the QMK Toolbox (recommended), or HID listen.
When `#define CONSOLE_IN_ENABLE` is placed in the `config.h` file, the keyboard will also listen to messages sent to the keyboard, will be able to respond in a custom way, defined at the `quantum`, `kb`, or `user` level. A keymap's example might look like this:
```c
void process_console_data_user(uint8_t * data, uint8_t length) {
switch (data[0]) {
case 0x05:
print("Sending back a message to the computer\n");
break;
}
}
```
Which will execute when a report is sent to the keyboard when the first byte is `0x05`.
## Default actions (defined at the `quantum` level)
When the first byte is:
* `0x01`: Print "Saying hello\n" via the console, and play the audio on song
* `0xFE`: Enter the bootloader - only works when `CONSOLE_IN_BOOTLOADER` is defined in the `config.h`
This needs to be fleshed out a bit more with some sort of versioning.