qmk-firmware/docs/feature_dynamic_macros.md

Dynamic Macros: Record and Replay Macros in Runtime

QMK supports temporary macros created on the fly. We call these Dynamic Macros. They are defined by the user from the keyboard and are lost when the keyboard is unplugged or otherwise rebooted.

You can store one or two macros and they may have a combined total of 128 keypresses. You can increase this size at the cost of RAM.

To enable them, first add a new element to the end of your keycodes enum — DYNAMIC_MACRO_RANGE:

enum keycodes {
	QWERTY = SAFE_RANGE,
	COLEMAK,
	DVORAK,
	PLOVER,
	LOWER,
	RAISE,
	BACKLIT,
	EXT_PLV,
	DYNAMIC_MACRO_RANGE,
};

Your keycodes enum may have a slightly different name. You must add DYNAMIC_MACRO_RANGE as the last element because dynamic_macros.h will add some more keycodes after it.

Below it, include the dynamic_macro.h header:

	#include "dynamic_macro.h"`

Add the following keys to your keymap:

• DYN_REC_START1 — start recording the macro 1,
• DYN_REC_START2 — start recording the macro 2,
• DYN_MACRO_PLAY1 — replay the macro 1,
• DYN_MACRO_PLAY2 — replay the macro 2,
• DYN_REC_STOP — finish the macro that is currently being recorded.

Add the following code to the very beginning of your process_record_user() function:

	if (!process_record_dynamic_macro(keycode, record)) {
		return false;
	}

That should be everything necessary. To start recording the macro, press either DYN_REC_START1 or DYN_REC_START2. To finish the recording, press the DYN_REC_STOP layer button. To replay the macro, press either DYN_MACRO_PLAY1 or DYN_MACRO_PLAY2.

Note that it's possible to replay a macro as part of a macro. It's ok to replay macro 2 while recording macro 1 and vice versa but never create recursive macros i.e. macro 1 that replays macro 1. If you do so and the keyboard will get unresponsive, unplug the keyboard and plug it again.

For users of the earlier versions of dynamic macros: It is still possible to finish the macro recording using just the layer modifier used to access the dynamic macro keys, without a dedicated DYN_REC_STOP key. If you want this behavior back, use the following snippet instead of the one above:

	uint16_t macro_kc = (keycode == MO(_DYN) ? DYN_REC_STOP : keycode);

	if (!process_record_dynamic_macro(macro_kc, record)) {
		return false;
	}

If the LEDs start blinking during the recording with each keypress, it means there is no more space for the macro in the macro buffer. To fit the macro in, either make the other macro shorter (they share the same buffer) or increase the buffer size by setting the DYNAMIC_MACRO_SIZE preprocessor macro (default value: 128; please read the comments for it in the header).

For the details about the internals of the dynamic macros, please read the comments in the dynamic_macro.h header.