1 files changed, 43 insertions, 3 deletions

diff --git a/readme.md b/readme.md
index a7320202b..d5a259ccb 100644
--- a/readme.md
+++ b/readme.md
@@ -140,6 +140,9 @@ If this is a bit complex for you, Docker might be the turn-key solution you need
 
 docker run -e keymap=gwen -e keyboard=ergodox --rm -v $('pwd'):/qmk:rw edasque/qmk_firmware
 
+# On windows docker seems to have issue with VOLUME tag in Dockerfile, and $('pwd') won't print a windows compliant path, use full path instead like this
+docker run -e keymap=default -e keyboard=ergobop --rm -v D:/Users/Sacapuces/Documents/Repositories/qmk:/qmk:rw edasque/qmk_firmware
+
 ```
 
 This will compile the targetted keyboard/keymap and leave it in your QMK directory for you to flash.
@@ -320,6 +323,18 @@ This enables MIDI sending and receiving with your keyboard. To enter MIDI send m
 
 This allows you to send unicode symbols via `UC(<unicode>)` in your keymap. Only codes up to 0x7FFF are currently supported.
 
+`UNICODEMAP_ENABLE`
+
+This allows sending unicode symbols using `X(<unicode>)` in your keymap. Codes
+up to 0xFFFFFFFF are supported, including emojis. You will need to maintain
+a separate mapping table in your keymap file.
+
+Known limitations:
+- Under Mac OS, only codes up to 0xFFFF are supported.
+- Under Linux ibus, only codes up to 0xFFFFF are supported (but anything important is still under this limit for now).
+
+Characters out of range supported by the OS will be ignored.
+
 `BLUETOOTH_ENABLE`
 
 This allows you to interface with a Bluefruit EZ-key to send keycodes wirelessly. It uses the D2 and D3 pins.
@@ -328,6 +343,10 @@ This allows you to interface with a Bluefruit EZ-key to send keycodes wirelessly
 
 This allows you output audio on the C6 pin (needs abstracting). See the [audio section](#driving-a-speaker---audio-support) for more information.
 
+`VARIABLE_TRACE`
+
+Use this to debug changes to variable values, see the [tracing variables](#tracing-variables) section for more information.
+
 ### Customizing Makefile options on a per-keymap basis
 
 If your keymap directory has a file called `Makefile` (note the filename), any Makefile options you set in that file will take precedence over other Makefile options for your particular keyboard.
@@ -376,6 +395,8 @@ Instead of using `FNx` when defining `ACTION_*` functions, you can use `F(x)` -
 
 `TG(layer)` - toggles a layer on or off. As with `MO()`, you should set this key as `KC_TRNS` in the destination layer so that tapping it again actually toggles back to the original layer. Only works upwards in the layer stack.
 
+`TO(layer)` - Goes to a layer. This code is special, because it lets you go either up or down the stack -- just goes directly to the layer you want. So while other codes only let you go _up_ the stack (from layer 0 to layer 3, for example), `TO(2)` is going to get you to layer 2, no matter where you activate it from -- even if you're currently on layer 5. This gets activated on keydown (as soon as the key is pressed).
+
 
 ### Fun with modifier keys
 
@@ -823,7 +844,7 @@ And then, to assign this macro to a key on your keyboard layout, you just use `M
 
 ## Dynamic macros: record and replay macros in runtime
 
-In addition to the static macros described above, you may enable the dynamic macros which you may record while writing. They are forgotten as soon as the keyboard is unplugged. Only two such macros may be stored at the same time, with the total length of 128 keypresses.
+In addition to the static macros described above, you may enable the dynamic macros which you may record while writing. They are forgotten as soon as the keyboard is unplugged. Only two such macros may be stored at the same time, with the total length of 64 keypresses (by default).
 
 To enable them, first add a new element to the `planck_keycodes` enum -- `DYNAMIC_MACRO_RANGE`:
 
@@ -864,7 +885,7 @@ Add the following code to the very beginning of your `process_record_user()` fun
 
 To start recording the macro, press either `DYN_REC_START1` or `DYN_REC_START2`. To finish the recording, press the `_DYN` layer button. The handler awaits specifically for the `MO(_DYN)` keycode as the "stop signal" so please don't use any fancy ways to access this layer, use the regular `MO()` modifier. To replay the macro, press either `DYN_MACRO_PLAY1` or `DYN_MACRO_PLAY2`.
 
-If the LED-s 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: 256; please read the comments for it in the header).
+If the LED-s 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.
 
@@ -889,7 +910,7 @@ In `quantum/keymap_extras/`, you'll see various language files - these work the
 
 ## Unicode support
 
-You can currently send 4 hex digits with your OS-specific modifier key (RALT for OSX with the "Unicode Hex Input" layout) - this is currently limited to supporting one OS at a time, and requires a recompile for switching. 8 digit hex codes are being worked on. The keycode function is `UC(n)`, where *n* is a 4 digit hexidecimal. Enable from the Makefile.
+You can currently send 4 hex digits with your OS-specific modifier key (RALT for OSX with the "Unicode Hex Input" layout, see [this article](http://www.poynton.com/notes/misc/mac-unicode-hex-input.html) to learn more) - this is currently limited to supporting one OS at a time, and requires a recompile for switching. 8 digit hex codes are being worked on. The keycode function is `UC(n)`, where *n* is a 4 digit hexidecimal. Enable from the Makefile.
 
 ## Backlight Breathing
 
@@ -1266,3 +1287,22 @@ If there are problems with the tests, you can find the executable in the `./buil
 It's not yet possible to do a full integration test, where you would compile the whole firmware and define a keymap that you are going to test. However there are plans for doing that, because writing tests that way would probably be easier, at least for people that are not used to unit testing.
 
 In that model you would emulate the input, and expect a certain output from the emulated keyboard.
+
+# Tracing variables 
+
+Sometimes you might wonder why a variable gets changed and where, and this can be quite tricky to track down without having a debugger. It's of course possible to manually add print statements to track it, but you can also enable the variable trace feature. This works for both for variables that are changed by the code, and when the variable is changed by some memory corruption.
+
+To take the feature into use add `VARIABLE_TRACE=x` to the end of you make command. `x` represents the number of variables you want to trace, which is usually 1. 
+
+Then at a suitable place in the code, call `ADD_TRACED_VARIABLE`, to begin the tracing. For example to trace all the layer changes, you can do this
+```c
+void matrix_init_user(void) {
+  ADD_TRACED_VARIABLE("layer", &layer_state, sizeof(layer_state));
+}
+```
+
+This will add a traced variable named "layer" (the name is just for your information), which tracks the memory location of `layer_state`. It tracks 4 bytes (the size of `layer_state`), so any modification to the variable will be reported. By default you can not specify a size bigger than 4, but you can change it by adding `MAX_VARIABLE_TRACE_SIZE=x` to the end of the make command line.
+
+In order to actually detect changes to the variables you should call `VERIFY_TRACED_VARIABLES` around the code that you think that modifies the variable. If a variable is modified it will tell you between which two `VERIFY_TRACED_VARIABLES` calls the modification happened. You can then add more calls to track it down further. I don't recommend spamming the codebase with calls. It's better to start with a few, and then keep adding them in a binary search fashion. You can also delete the ones you don't need, as each call need to store the file name and line number in the ROM, so you can run out of memory if you add too many calls.
+
+Also remember to delete all the tracing code ones you have found the bug, as you wouldn't want to create a pull request with tracing code.
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