Restructure the hardware and feature docs to make things easier to find (#1888)

* fix #1313 by documenting more config.h options

* Clean up and organize documentation

1 files changed, 220 insertions, 0 deletions

diff --git a/docs/feature_macros.md b/docs/feature_macros.md
new file mode 100644
index 000000000..66d2bc090
--- /dev/null
+++ b/docs/feature_macros.md
@@ -0,0 +1,220 @@
+# Macros
+
+Macros allow you to send multiple keystrokes when pressing just one key. QMK has a number of ways to define and use macros. These can do anything you want: type common phrases for you, copypasta, repetitive game movements, or even help you code. 
+
+{% hint style='danger' %}
+**Security Note**: While it is possible to use macros to send passwords, credit card numbers, and other sensitive information it is a supremely bad idea to do so. Anyone who gets ahold of your keyboard will be able to access that information by opening a text editor.
+{% endhint %}
+
+## The new way: `SEND_STRING()` & `process_record_user`
+
+Sometimes you just want a key to type out words or phrases. For the most common situations we've provided `SEND_STRING()`, which will type out your string for you. All ascii that is easily translated to a keycode is supported (eg `\n\t`).
+
+For example:
+
+```c
+enum custom_keycodes {
+	PRINT_TRUTH = SAFE_RANGE
+};
+
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+	if (record->event.pressed) {
+		switch(keycode) {
+			case PRINT_TRUTH:
+				SEND_STRING("QMK is the best thing ever!");
+				return false; break;
+		}
+	}
+	return true;
+};
+```
+
+### Tap/down/up
+
+You can send arbitary keycodes by wrapping them in:
+
+* `SS_TAP()`
+* `SS_DOWN()`
+* `SS_UP()`
+
+For example:
+
+    SEND_STRING(SS_TAP(X_HOME));
+
+Would tap `KC_HOME` - note how the prefix is now `X_`, and not `KC_`. You can also combine this with other strings, like this:
+
+    SEND_STRING("VE"SS_TAP(X_HOME)"LO");
+
+Which would send "VE" followed by a `KC_HOME` tap, and "LO" (spelling "LOVE" if on a newline).
+
+There's also a couple of mod shortcuts you can use:
+
+* `SS_LCTRL(string)`
+* `SS_LGUI(string)`
+* `SS_LALT(string)`
+
+That can be used like this:
+
+    SEND_STRING(SS_LCTRL("a"));
+
+Which would send LCTRL+a (LTRL down, a, LTRL up) - notice that they take strings (eg `"k"`), and not the `X_K` keycodes.
+
+### Alternative keymaps
+
+By default, it assumes a US keymap with a QWERTY layout; if you want to change that (e.g. if your OS uses software Colemak), include this somewhere in your keymap:
+
+    #include <sendstring_colemak.h>
+
+### Strings in memory
+
+If for some reason you're manipulating strings and need to print out something you just generated (instead of being a literal, constant string), you can use `send_string()`, like this:
+
+```c
+char my_str[4] = "ok.";
+send_string(my_str);
+```
+
+The shortcuts defined above won't work with `send_string()`, but you can separate things out to different lines if needed:
+
+```c
+char my_str[4] = "ok.";
+SEND_STRING("I said: ");
+send_string(my_str);
+SEND_STRING(".."SS_TAP(X_END));
+```
+
+## The old way: `MACRO()` & `action_get_macro`
+
+{% hint style='info' %}
+This is inherited from TMK, and hasn't been updated - it's recommend that you use `SEND_STRING` and `process_record_user` instead.
+{% endhint %}
+
+By default QMK assumes you don't have any macros. To define your macros you create an `action_get_macro()` function. For example:
+
+```c
+const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
+	if (record->event.pressed) {
+		switch(id) {
+			case 0:
+				return MACRO(D(LSFT), T(H), U(LSFT), T(I), D(LSFT), T(1), U(LSFT), END);
+			case 1:
+				return MACRO(D(LSFT), T(B), U(LSFT), T(Y), T(E), D(LSFT), T(1), U(LSFT), END);
+		}
+	}
+	return MACRO_NONE;
+};
+```
+
+This defines two macros which will be run when the key they are assigned to is pressed. If instead you'd like them to run when the key is released you can change the if statement:
+
+	if (!record->event.pressed) {
+
+### Macro Commands
+
+A macro can include the following commands:
+
+* I() change interval of stroke in milliseconds.
+* D() press key.
+* U() release key.
+* T() type key(press and release).
+* W() wait (milliseconds).
+* END end mark.
+
+### Mapping a Macro to a key
+
+Use the `M()` function within your `KEYMAP()` to call a macro. For example, here is the keymap for a 2-key keyboard:
+
+```c
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+	[0] = KEYMAP(
+		M(0), M(1)
+	),
+};
+
+const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
+	if (record->event.pressed) {
+		switch(id) {
+			case 0:
+				return MACRO(D(LSFT), T(H), U(LSFT), T(I), D(LSFT), T(1), U(LSFT), END);
+			case 1:
+				return MACRO(D(LSFT), T(B), U(LSFT), T(Y), T(E), D(LSFT), T(1), U(LSFT), END);
+		}
+	}
+	return MACRO_NONE;
+};
+```
+
+When you press the key on the left it will type "Hi!" and when you press the key on the right it will type "Bye!".
+
+### Naming your macros
+
+If you have a bunch of macros you want to refer to from your keymap while keeping the keymap easily readable you can name them using `#define` at the top of your file.
+
+```c
+#define M_HI M(0)
+#define M_BYE M(1)
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+	[0] = KEYMAP(
+		M_HI, M_BYE
+	),
+};
+```
+
+## Advanced macro functions
+
+There are some functions you may find useful in macro-writing. Keep in mind that while you can write some fairly advanced code within a macro if your functionality gets too complex you may want to define a custom keycode instead. Macros are meant to be simple.
+
+### `record->event.pressed`
+
+This is a boolean value that can be tested to see if the switch is being pressed or released. An example of this is
+
+```c
+	if (record->event.pressed) {
+		// on keydown
+	} else {
+		// on keyup
+	}
+```
+
+### `register_code(<kc>);`
+
+This sends the `<kc>` keydown event to the computer. Some examples would be `KC_ESC`, `KC_C`, `KC_4`, and even modifiers such as `KC_LSFT` and `KC_LGUI`.
+
+### `unregister_code(<kc>);`
+
+Parallel to `register_code` function, this sends the `<kc>` keyup event to the computer. If you don't use this, the key will be held down until it's sent.
+
+### `clear_keyboard();`
+
+This will clear all mods and keys currently pressed.
+
+### `clear_mods();`
+
+This will clear all mods currently pressed.
+
+### `clear_keyboard_but_mods();`
+
+This will clear all keys besides the mods currently pressed.
+
+## Advanced Example: Single-key copy/paste
+
+This example defines a macro which sends `Ctrl-C` when pressed down, and `Ctrl-V` when released. 
+
+```c
+const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
+	switch(id) {
+		case 0: {
+			if (record->event.pressed) {
+				return MACRO( D(LCTL), T(C), U(LCTL), END  );
+			} else {
+				return MACRO( D(LCTL), T(V), U(LCTL), END  );
+			}
+			break;
+		}
+	}
+	return MACRO_NONE;
+};
+```
+
+