2021 May 29 Breaking Changes Update (#13034)

* Add Per Key functionality for AutoShift (#11536)

* LED Matrix: Reactive effect buffers & advanced indicators (#12588)

* [Keyboard] kint36: switch to sym_eager_pk debouncing (#12626)

* [Keyboard] kint2pp: reduce input latency by ≈10ms (#12625)

* LED Matrix: Split (#12633)

* [CI] Format code according to conventions (#12650)

* feat: infinite timeout for leader key (#6580)

* feat: implement leader_no_timeout logic

* docs(leader_key): infinite leader timeout docs

* Format code according to conventions (#12680)

* Update ADC driver for STM32F1xx, STM32F3xx, STM32F4xx (#12403)

* Fix default ADC_RESOLUTION for ADCv3 (and ADCv4)

Recent ChibiOS update removed ADC_CFGR1_RES_10BIT from the ADCv3 headers
(that macro should not have been there, because ADCv3 has CFGR instead of
CFGR1).  Fix the default value for ADC_RESOLUTION to use ADC_CFGR_RES_10BITS
if it is defined (that name is used for ADCv3 and ADCv4).

* Update ADC docs to match the actually used resolution

ADC driver for ChibiOS actually uses the 10-bit resolution by default
(probably to match AVR); fix the documentation accordingly.  Also add
both ADC_CFGR_RES_10BITS and ADC_CFGR1_RES_10BIT constants (these names
differ according to the ADC implementation in the particular MCU).

* Fix pinToMux() for B12 and B13 on STM32F3xx

Testing on STM32F303CCT6 revealed that the ADC mux values for B12 and
B13 pins were wrong.

* Add support for all possible analog pins on STM32F1xx

Added ADC mux values for pins A0...A7, B0, B1, C0...C5 on STM32F1xx
(they are the same at least for STM32F103x8 and larger F103 devices, and
also F102, F105, F107 families).  Actually tested on STM32F103C8T6
(therefore pins C0...C5 were not tested).

Pins F6...F10, which are present on STM32F103x[C-G] in 144-pin packages,
cannot be supported at the moment, because those pins are connected only
to ADC3, but the ChibiOS ADC driver for STM32F1xx supports only ADC1.

* Add support for all possible analog pins on STM32F4xx

Added ADC mux values for pins A0...A7, B0, B1, C0...C5 and optionally
F3...F10 (if STM32_ADC_USE_ADC3 is enabled).  These mux values are
apparently the same for all F4xx devices, except some smaller devices may
not have ADC3.

Actually tested on STM32F401CCU6, STM32F401CEU6, STM32F411CEU6 (using
various WeAct “Blackpill” boards); only pins A0...A7, B0, B1 were tested.

Pins F3...F10 are inside `#if STM32_ADC_USE_ADC3` because some devices
which don't have ADC3 also don't have the GPIOF port, therefore the code
which refers to Fx pins does not compile.

* Fix STM32F3xx ADC mux table in documentation

The ADC driver documentation had some errors in the mux table for STM32F3xx.
Fix this table to match the datasheet and the actual code (mux settings for
B12 and B13 were also tested on a real STM32F303CCT6 chip).

* Add STM32F1xx ADC pins to the documentation

* Add STM32F4xx ADC pins to the documentation

* Add initial support for tinyuf2 bootloader (when hosted on F411 blackpill) (#12600)

* Add support for jumping to tinyuf2 bootloader. Adds blackpill UF2 example.

* Update flashing.md

* Update chconf.h

* Update config.h

* Update halconf.h

* Update mcuconf.h

* eeprom driver: Refactor where eeprom driver initialisation (and EEPROM emulation initialisation) occurs to make it non-target-specific. (#12671)

* Add support for MCU = STM32F446 (#12619)

* Add support for MCU = STM32F446

* Update platforms/chibios/GENERIC_STM32_F446XE/configs/config.h

* Restore mcuconf.h to the one used by RT-STM32F446RE-NUCLEO64

* stm32f446: update mcuconf.h and board.h for 16MHz operation, with USB enabled, and other peripherals disabled.

* Format code according to conventions (#12682)

* Format code according to conventions (#12687)

* Add STM32L433 and L443 support (#12063)

* initial L433 commit

* change to XC

* fix L433

* disable all peripherals

* update system and peripheral clocks

* 433 change

* use its own board  files

* revert its own board files

* l433 specific change

* fix stm32l432xx define

* remove duplicate #define

* fix bootloader jump

* move to L443xx and add i2c2, spi2, usart3 to mcuconf.h

* move to L443

* move to L443

* fix sdmmc in mcuconf.h

* include STM32L443

* add L443

* Include L443 in compatible microcontrollers

* Include L443 in compatible microcontrollers

* Update config bootloader jump description

* Update ChibiOS define reasoning

* Update quantum/mcu_selection.mk

* fix git conflict

* Updated Function96 with V2 files and removed chconf.h and halconf.h (#12613)

* Fix bad PR merge for #6580. (#12721)

* Change RGB/LED Matrix to use a simple define for USB suspend (#12697)

* [CI] Format code according to conventions (#12731)

* Fixing transport's led/rgb matrix suspend state logic (#12770)

* [CI] Format code according to conventions (#12772)

* Fix comment parsing (#12750)

* Added OLED fade out support (#12086)

* fix some references to bin/qmk that slipped in (#12832)

* Resolve a number of warnings in `qmk generate-api` (#12833)

* New command: qmk console (#12828)

* stash poc

* stash

* tidy up implementation

* Tidy up slightly for review

* Tidy up slightly for review

* Bodge environment to make tests pass

* Refactor away from asyncio due to windows issues

* Filter devices

* align vid/pid printing

* Add hidapi to the installers

* start preparing for multiple hid_listeners

* udev rules for hid_listen

* refactor to move closer to end state

* very basic implementation of the threaded model

* refactor how vid/pid/index are supplied and parsed

* windows improvements

* read the report directly when usage page isn't available

* add per-device colors, the choice to show names or numbers, and refactor

* add timestamps

* Add support for showing bootloaders

* tweak the color for bootloaders

* Align bootloader disconnect with connect color

* add support for showing all bootloaders

* fix the pyusb check

* tweaks

* fix exception

* hide a stack trace behind -v

* add --no-bootloaders option

* add documentation for qmk console

* Apply suggestions from code review

* pyformat

* clean up and flesh out KNOWN_BOOTLOADERS

* Remove pointless SERIAL_LINK_ENABLE rules (#12846)

* Make Swap Hands use PROGMEM (#12284)

This converts the array that the Swap Hands feature uses to use PROGMEM,
and to read from that array, as such. Since this array never changes at
runtime, there is no reason to keep it in memory. Especially for AVR
boards, as memory is a precious resource.

* Fix another bin/qmk reference (#12856)

* [Keymap] Turn OLED off on suspend in soundmonster keymap (#10419)

* Fixup build errors on `develop` branch. (#12723)

* LED Matrix: Effects! (#12651)

* Fix syntax error when compiling for ARM (#12866)

* Remove KEYMAP and LAYOUT_kc (#12160)

* alias KEYMAP to LAYOUT

* remove KEYMAP and LAYOUT_kc

* Add setup, clone, and env to the list of commands we allow even with broken modules (#12868)

* Rename `point_t` -> `led_point_t` (#12864)

* [Keyboard] updated a vendor name / fixed minor keymap issues (#12881)

* Add missing LED Matrix suspend code to suspend.c (#12878)

* LED Matrix: Documentation (#12685)

* Deprecate `send_unicode_hex_string()` (#12602)

* Fix spelling mistake regarding LED Matrix in split_common. (#12888)

* [Keymap] Fix QWERTY/DVORAK status output for kzar keymap (#12895)

* Use milc.subcommand.config instead of qmk.cli.config (#12915)

* Use milc.subcommand.config instead

* pyformat

* remove the config test

* Add function to allow repeated blinking of one layer (#12237)

* Implement function rgblight_blink_layer_repeat to allow repeated blinking of one layer at a time

* Update doc

* Rework rgblight blinking according to requested change

* optimize storage

* Fixup housekeeping from being invoked twice per loop. (#12933)

* matrix: wait for row signal to go HIGH for every row (#12945)

I noticed this discrepancy (last row of the matrix treated differently than the
others) when optimizing the input latency of my keyboard controller, see also
https://michael.stapelberg.ch/posts/2021-05-08-keyboard-input-latency-qmk-kinesis/

Before this commit, when tuning the delays I noticed ghost key presses when
pressing the F2 key, which is on the last row of the keyboard matrix: the
dead_grave key, which is on the first row of the keyboard matrix, would be
incorrectly detected as pressed.

After this commit, all keyboard matrix rows are interpreted correctly.

I suspect that my setup is more susceptible to this nuance than others because I
use GPIO_INPUT_PIN_DELAY=0 and hence don’t have another delay that might mask
the problem.

* ensure we do not conflict with existing keymap aliases (#12976)

* Add support for up to 4 IS31FL3733 drivers (#12342)

* Convert Encoder callbacks to be boolean functions (#12805)

* [Keyboard] Fix Terrazzo build failure (#12977)

* Do not hard set config in CPTC files (#11864)

* [Keyboard] Corne - Remove legacy revision support (#12226)

* [Keymap] Update to Drashna keymap and user code (based on develop) (#12936)

* Add Full-duplex serial driver for ARM boards (#9842)

* Document LED_MATRIX_FRAMEBUFFER_EFFECTS (#12987)

* Backlight: add defines for default level and breathing state (#12560)

* Add dire message about LUFA mass storage bootloader (#13014)

* [Keyboard] Remove redundant legacy and common headers for crkbd (#13023)

Was causing compiler errors on some systems.

* Fix keyboards/keymaps for boolean encoder callback changes (#12985)

* `backlight.c`: include `eeprom.h` (#13024)

* Add changelog for 2021-05-29 Breaking Changes merge (#12939)

* Add ChangeLog for 2021-05-29 Breaking Changes Merge: initial version

* Add recent develop changes

* Sort recent develop changes

* Remove sections for ChibiOS changes per tzarc

No ChibiOS changes this round.

* Add and sort recent develop changes

* add notes about keyboard moves/deletions

* import changelog for PR 12172

Documents the change to BOOTMAGIC_ENABLE.

* update section headings

* re-sort changelog

* add additional note regarding Bootmagic changes

* remove changelog timestamp

* update dates in main Breaking Changes docs

* fix broken section anchors in previous changelogs

* add link to backlight/eeprom patch to changelog

* highlight some more changes

* link PRs from section headers

* Restore standard readme

* run: qmk cformat --core-only

27 files changed, 368 insertions, 220 deletions

diff --git a/users/arkag/arkag.c b/users/arkag/arkag.c
index 564c234c39..ea716ecdab 100644
--- a/users/arkag/arkag.c
+++ b/users/arkag/arkag.c
@@ -363,7 +363,7 @@ void matrix_scan_user(void) {
       surround_type(4, KC_GRAVE, true);
     }
     SEQ_ONE_KEY(KC_C) {
-      send_unicode_hex_string("00E7");
+      register_unicode(0x00E7); // ç
     }
     SEQ_TWO_KEYS(KC_A, KC_V) {
       surround_type(2, KC_QUOT, true);
@@ -384,10 +384,10 @@ void matrix_scan_user(void) {
       surround_type(6, KC_GRAVE, false);
     }
     SEQ_ONE_KEY(KC_E) {
-      send_unicode_hex_string("00E8");
+      register_unicode(0x00E8); // è
     }
     SEQ_TWO_KEYS(KC_E, KC_E) {
-      send_unicode_hex_string("00E9");
+      register_unicode(0x00E9); // é
     }
     // end format functions
 
@@ -407,8 +407,7 @@ void matrix_scan_user(void) {
 
     // start typing functions
     SEQ_TWO_KEYS(KC_T, KC_M) {
-      // ™
-      send_unicode_hex_string("2122");
+      register_unicode(0x2122); // ™
     }
     SEQ_TWO_KEYS(KC_D, KC_D) {
       SEND_STRING(".\\Administrator");
@@ -420,27 +419,22 @@ void matrix_scan_user(void) {
       tap_code(KC_ENTER);
     }
     SEQ_THREE_KEYS(KC_L, KC_O, KC_D) {
-      // ಠ__ಠ
-      send_unicode_hex_string("0CA0 005F 005F 0CA0");
+      send_unicode_string("ಠ__ಠ");
     }
     SEQ_THREE_KEYS(KC_M, KC_A, KC_P) {
       SEND_STRING("https://github.com/qmk/qmk_firmware/tree/master/users/arkag");
     }
     SEQ_TWO_KEYS(KC_F, KC_F) {
-      // (╯‵Д′)╯彡┻━┻
-      send_unicode_hex_string("0028 256F 2035 0414 2032 0029 256F 5F61 253B 2501 253B");
+      send_unicode_string("(╯‵Д′)╯彡┻━┻");
     }
     SEQ_THREE_KEYS(KC_F, KC_F, KC_F) {
-      // ┬─┬ノ( º _ º ノ)
-      send_unicode_hex_string("252C 2500 252C 30CE 0028 0020 00BA 0020 005F 0020 00BA 0020 30CE 0029");
+      send_unicode_string("┬─┬ノ( º _ º ノ)");
     }
     SEQ_THREE_KEYS(KC_L, KC_O, KC_L) {
-      // ( ͡° ͜ʖ ͡°)
-      send_unicode_hex_string("0028 0020 0361 00B0 0020 035C 0296 0020 0361 00B0 0029");
+      send_unicode_string("( ͡° ͜ʖ ͡°)");
     }
     SEQ_THREE_KEYS(KC_S, KC_S, KC_S) {
-      // ¯\_(ツ)_/¯
-      send_unicode_hex_string("00AF 005C 005F 0028 30C4 0029 005F 002F 00AF");
+      send_unicode_string("¯\\_(ツ)_/¯");
     }
     // end typing functions
 
@@ -513,7 +507,7 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
 
   case M_DASH:
     if (record->event.pressed){
-      send_unicode_hex_string("2014");
+      register_unicode(0x2014); // —
     }
     return false;
   case M_LMHYP:
diff --git a/users/curry/process_records.c b/users/curry/process_records.c
index fd58ea181b..3b5c001926 100644
--- a/users/curry/process_records.c
+++ b/users/curry/process_records.c
@@ -46,24 +46,24 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
             }
             break;
 #if defined(UNICODE_ENABLE)
-        case UC_FLIP:  // (ノಠ痊ಠ)ノ彡┻━┻
+        case UC_FLIP:
             if (record->event.pressed) {
-                send_unicode_hex_string("0028 30CE 0CA0 75CA 0CA0 0029 30CE 5F61 253B 2501 253B");
+                send_unicode_string("(ノಠ痊ಠ)ノ彡┻━┻");
             }
             break;
-        case UC_TABL:  // ┬─┬ノ( º _ ºノ)
+        case UC_TABL:
             if (record->event.pressed) {
-                send_unicode_hex_string("252C 2500 252C 30CE 0028 0020 00BA 0020 005F 0020 00BA 30CE 0029");
+                send_unicode_string("┬─┬ノ( º _ ºノ)");
             }
             break;
-        case UC_SHRG:  // ¯\_(ツ)_/¯
+        case UC_SHRG:
             if (record->event.pressed) {
-                send_unicode_hex_string("00AF 005C 005F 0028 30C4 0029 005F 002F 00AF");
+                send_unicode_string("¯\\_(ツ)_/¯");
             }
             break;
-        case UC_DISA:  // ಠ_ಠ
+        case UC_DISA:
             if (record->event.pressed) {
-                send_unicode_hex_string("0CA0 005F 0CA0");
+                send_unicode_string("ಠ_ಠ");
             }
             break;
 #endif
diff --git a/users/d4mation/macros.c b/users/d4mation/macros.c
index 3c115d7ead..a8ca119b12 100644
--- a/users/d4mation/macros.c
+++ b/users/d4mation/macros.c
@@ -45,75 +45,75 @@ bool process_record_user( uint16_t keycode, keyrecord_t *record ) {
 
     #ifdef UNICODE_ENABLE
 
-      case AMENO:  /* ༼ つ ◕_◕ ༽つ */
+      case AMENO:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "0F3C 0020 3064 0020 25D5 005F 25D5 0020 0F3D 3064" );
+          send_unicode_string( "༼ つ ◕_◕ ༽つ" );
 
         }
 
         return false;
         break;
 
-      case MAGIC:  /* (∩ ͡° ͜ʖ ͡°)⊃━☆ﾟ. * */
+      case MAGIC:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "0028 2229 0020 0361 00B0 0020 035C 0296 0020 0361 00B0 0029 2283 2501 2606 FF9F 002E 0020 002A" );
+          send_unicode_string( "(∩ ͡° ͜ʖ ͡°)⊃━☆ﾟ. *" );
 
         }
 
         return false;
         break;
 
-      case LENNY:  /* ( ͡° ͜ʖ ͡°) */
+      case LENNY:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "0028 0020 0361 00B0 0020 035C 0296 0020 0361 00b0 0029" );
+          send_unicode_string( "( ͡° ͜ʖ ͡°)" );
 
         }
 
         return false;
         break;
 
-      case DISFACE:  /* ಠ_ಠ */
+      case DISFACE:
 
         if ( record->event.pressed ) {
-          send_unicode_hex_string( "0CA0 005F 0CA0" );
+          send_unicode_string( "ಠ_ಠ" );
         }
 
         return false;
         break;
 
-      case TFLIP:  /* (╯°□°)╯ ︵ ┻━┻ */
+      case TFLIP:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "0028 256F 00b0 25A1 00B0 0029 256F FE35 253B 2501 253B" );
+          send_unicode_string( "(╯°□°)╯︵┻━┻" );
 
         }
 
         return false;
         break;
 
-      case TPUT:  /* ┬──┬ ノ( ゜-゜ノ) */
+      case TPUT:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "252C 2500 2500 252C 0020 30CE 0028 0020 309C 002D 309C 30CE 0029" );
+          send_unicode_string( "┬──┬ ノ( ゜-゜ノ)" );
 
         }
 
         return false;
         break;
 
-      case SHRUG:  /* ¯\_(ツ)_/¯ */
+      case SHRUG:
 
         if ( record->event.pressed ) {
 
-          send_unicode_hex_string( "00AF 005C 005F 0028 30C4 0029 005F 002F 00AF" );
+          send_unicode_string( "¯\\_(ツ)_/¯" );
 
         }
 
diff --git a/users/drashna/config.h b/users/drashna/config.h
index 8081af9cc3..5f7c32ff35 100644
--- a/users/drashna/config.h
+++ b/users/drashna/config.h
@@ -24,7 +24,7 @@
 
 #if defined(SPLIT_KEYBOARD)
 #    define SPLIT_MODS_ENABLE
-// #    define SPLIT_TRANSPORT_MIRROR
+#    define SPLIT_TRANSPORT_MIRROR
 #    define SERIAL_USE_MULTI_TRANSACTION
 // #    define SPLIT_NUM_TRANSACTIONS_KB 2
 #endif
@@ -56,6 +56,8 @@
 #    else
 #        define RGBLIGHT_ANIMATIONS
 #    endif
+#    define RGBLIGHT_EFFECT_TWINKLE_LIFE  250
+#    define RGBLIGHT_EFFECT_TWINKLE_PROBABILITY 1/24
 #endif  // RGBLIGHT_ENABLE
 
 #ifdef RGB_MATRIX_ENABLE
@@ -115,6 +117,9 @@
 #        define OLED_UPDATE_INTERVAL 15
 #    endif
 #    define OLED_DISABLE_TIMEOUT
+#    ifdef OLED_FONT_H
+#        undef OLED_FONT_H
+#    endif
 #    define OLED_FONT_H "drashna_font.h"
 #    define OLED_FONT_END 255
 // #    define OLED_FONT_5X5
@@ -149,7 +154,9 @@
 #undef PERMISSIVE_HOLD
 //#define TAPPING_FORCE_HOLD
 //#define RETRO_TAPPING
-#define TAPPING_TERM_PER_KEY
+#ifndef KEYBOARD_kyria_rev1
+#    define TAPPING_TERM_PER_KEY
+#endif
 
 #define FORCE_NKRO
 
diff --git a/users/drashna/drashna.c b/users/drashna/drashna.c
index 6a13f0d9b2..a493737262 100644
--- a/users/drashna/drashna.c
+++ b/users/drashna/drashna.c
@@ -164,6 +164,7 @@ layer_state_t layer_state_set_user(layer_state_t state) {
         return state;
     }
 
+    state = layer_state_set_keymap(state);
     state = update_tri_layer_state(state, _RAISE, _LOWER, _ADJUST);
 #if defined(RGBLIGHT_ENABLE)
     state = layer_state_set_rgb_light(state);
@@ -179,7 +180,7 @@ layer_state_t layer_state_set_user(layer_state_t state) {
         }
     }
 #endif
-    return layer_state_set_keymap(state);
+    return state;
 }
 
 __attribute__((weak)) layer_state_t default_layer_state_set_keymap(layer_state_t state) { return state; }
diff --git a/users/drashna/drashna.h b/users/drashna/drashna.h
index 9a18a82965..e66f106574 100644
--- a/users/drashna/drashna.h
+++ b/users/drashna/drashna.h
@@ -47,7 +47,6 @@ enum userspace_layers {
     _MALTRON,
     _EUCALYN,
     _CARPLAX,
-    _MODS, /* layer 8 */
     _GAMEPAD,
     _DIABLO,
     _MACROS,
diff --git a/users/drashna/drashna_transport.c b/users/drashna/drashna_transport.c
index f0908b4900..9df11c9bdf 100644
--- a/users/drashna/drashna_transport.c
+++ b/users/drashna/drashna_transport.c
@@ -21,6 +21,7 @@
 #include QMK_KEYBOARD_H
 
 #define ROWS_PER_HAND (MATRIX_ROWS / 2)
+#define SYNC_TIMER_OFFSET 2
 
 #ifdef RGBLIGHT_ENABLE
 #    include "rgblight.h"
@@ -37,19 +38,33 @@ static pin_t encoders_pad[] = ENCODERS_PAD_A;
 #endif
 
 #ifdef POINTING_DEVICE_ENABLE
-static int8_t split_mouse_x = 0, split_mouse_y = 0;
+static uint16_t device_cpi    = 0;
+static int8_t   split_mouse_x = 0, split_mouse_y = 0;
 #endif
 
 #ifdef OLED_DRIVER_ENABLE
 #    include "oled_driver.h"
 #endif
 
+#if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+#    include "led_matrix.h"
+#endif
+#if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+#    include "rgb_matrix.h"
+#endif
+
 #if defined(USE_I2C)
 
 #    include "i2c_master.h"
 #    include "i2c_slave.h"
 
 typedef struct _I2C_slave_buffer_t {
+#    ifndef DISABLE_SYNC_TIMER
+    uint32_t sync_timer;
+#    endif
+#    ifdef SPLIT_TRANSPORT_MIRROR
+    matrix_row_t mmatrix[ROWS_PER_HAND];
+#    endif
     matrix_row_t smatrix[ROWS_PER_HAND];
 #    ifdef SPLIT_MODS_ENABLE
     uint8_t real_mods;
@@ -70,19 +85,29 @@ typedef struct _I2C_slave_buffer_t {
 #    ifdef WPM_ENABLE
     uint8_t current_wpm;
 #    endif
+#    if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+    led_eeconfig_t led_matrix;
+    bool           led_suspend_state;
+#    endif
+#    if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+    rgb_config_t rgb_matrix;
+    bool         rgb_suspend_state;
+#    endif
     int8_t        mouse_x;
     int8_t        mouse_y;
+    uint16_t      device_cpi;
     bool          oled_on;
     layer_state_t t_layer_state;
     layer_state_t t_default_layer_state;
-    bool          is_rgb_matrix_suspended;
 } __attribute__((packed)) I2C_slave_buffer_t;
 
 static I2C_slave_buffer_t *const i2c_buffer = (I2C_slave_buffer_t *)i2c_slave_reg;
 
 #    define I2C_BACKLIGHT_START offsetof(I2C_slave_buffer_t, backlight_level)
 #    define I2C_RGB_START offsetof(I2C_slave_buffer_t, rgblight_sync)
-#    define I2C_KEYMAP_START offsetof(I2C_slave_buffer_t, smatrix)
+#    define I2C_KEYMAP_MASTER_START offsetof(I2C_slave_buffer_t, mmatrix)
+#    define I2C_KEYMAP_SLAVE_START offsetof(I2C_slave_buffer_t, smatrix)
+#    define I2C_SYNC_TIME_START offsetof(I2C_slave_buffer_t, sync_timer)
 #    define I2C_REAL_MODS_START offsetof(I2C_slave_buffer_t, real_mods)
 #    define I2C_WEAK_MODS_START offsetof(I2C_slave_buffer_t, weak_mods)
 #    define I2C_ONESHOT_MODS_START offsetof(I2C_slave_buffer_t, oneshot_mods)
@@ -90,10 +115,14 @@ static I2C_slave_buffer_t *const i2c_buffer = (I2C_slave_buffer_t *)i2c_slave_re
 #    define I2C_WPM_START offsetof(I2C_slave_buffer_t, current_wpm)
 #    define I2C_MOUSE_X_START offsetof(I2C_slave_buffer_t, mouse_x)
 #    define I2C_MOUSE_Y_START offsetof(I2C_slave_buffer_t, mouse_y)
+#    define I2C_MOUSE_DPI_START offsetof(I2C_slave_buffer_t, device_cpi)
 #    define I2C_OLED_ON_START offsetof(I2C_slave_buffer_t, oled_on)
 #    define I2C_LAYER_STATE_START offsetof(I2C_slave_buffer_t, t_layer_state)
 #    define I2C_DEFAULT_LAYER_STATE_START offsetof(I2C_slave_buffer_t, t_default_layer_state)
-#    define I2C_RGB_MATRIX_SUSPEND_START offsetof(I2C_slave_buffer_t, is_rgb_matrix_suspended)
+#    define I2C_LED_MATRIX_START offsetof(I2C_slave_buffer_t, led_matrix)
+#    define I2C_LED_SUSPEND_START offsetof(I2C_slave_buffer_t, led_suspend_state)
+#    define I2C_RGB_MATRIX_START offsetof(I2C_slave_buffer_t, rgb_matrix)
+#    define I2C_RGB_SUSPEND_START offsetof(I2C_slave_buffer_t, rgb_suspend_state)
 
 #    define TIMEOUT 100
 
@@ -102,9 +131,11 @@ static I2C_slave_buffer_t *const i2c_buffer = (I2C_slave_buffer_t *)i2c_slave_re
 #    endif
 
 // Get rows from other half over i2c
-bool transport_master(matrix_row_t matrix[]) {
-    i2c_readReg(SLAVE_I2C_ADDRESS, I2C_KEYMAP_START, (void *)matrix, sizeof(i2c_buffer->smatrix), TIMEOUT);
-
+bool transport_master(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
+    i2c_readReg(SLAVE_I2C_ADDRESS, I2C_KEYMAP_SLAVE_START, (void *)slave_matrix, sizeof(i2c_buffer->smatrix), TIMEOUT);
+#    ifdef SPLIT_TRANSPORT_MIRROR
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_KEYMAP_MASTER_START, (void *)master_matrix, sizeof(i2c_buffer->mmatrix), TIMEOUT);
+#    endif
     // write backlight info
 #    ifdef BACKLIGHT_ENABLE
     uint8_t level = is_backlight_enabled() ? get_backlight_level() : 0;
@@ -147,6 +178,12 @@ bool transport_master(matrix_row_t matrix[]) {
         i2c_readReg(SLAVE_I2C_ADDRESS, I2C_MOUSE_Y_START, (void *)&i2c_buffer->mouse_y, sizeof(i2c_buffer->mouse_y), TIMEOUT);
         temp_report.y = i2c_buffer->mouse_y;
         pointing_device_set_report(temp_report);
+
+        if (device_cpi != i2c_buffer->device_cpi) {
+            if (i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_MOUSE_DPI_START, (void *)&device_cpi, sizeof(device_cpi), TIMEOUT) >= 0) {
+                i2c_buffer->device_cpi = device_cpi
+            }
+        }
     }
 #    endif
 
@@ -188,29 +225,42 @@ bool transport_master(matrix_row_t matrix[]) {
     }
 
 #    ifdef OLED_DRIVER_ENABLE
-    bool is_oled = is_oled_on();
-    if (is_oled != i2c_buffer->oled_on) {
-        if (i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_LAYER_STATE_START, (void *)&is_oled, sizeof(is_oled), TIMEOUT) >= 0) {
-            i2c_buffer->oled_on = is_oled;
+    bool is_oled_on = is_oled_on();
+    if (is_oled_on != i2c_buffer->oled_on) {
+        if (i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_LAYER_STATE_START, (void *)&is_oled_on, sizeof(is_oled_on), TIMEOUT) >= 0) {
+            i2c_buffer->oled_on = is_oled_on;
         }
     }
 #    endif
 
-#    ifdef RGB_MATRIX_ENABLE
-    bool sus_state = rgb_matrix_get_suspend_state();
-    if (sus_state != i2c_buffer->is_rgb_matrix_suspended) {
-        if (i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_RGB_MATRIX_SUSPEND_START, (void *)&sus_state, sizeof(sus_state), TIMEOUT) >= 0) {
-            i2c_buffer->is_rgb_matrix_suspended = sus_state;
-        }
-    }
+#    if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_LED_MATRIX_START, (void *)led_matrix_eeconfig, sizeof(i2c_buffer->led_matrix), TIMEOUT);
+    bool suspend_state = led_matrix_get_suspend_state();
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_LED_SUSPEND_START, (void *)suspend_state, sizeof(i2c_buffer->led_suspend_state), TIMEOUT);
+#    endif
+#    if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_RGB_MATRIX_START, (void *)rgb_matrix_config, sizeof(i2c_buffer->rgb_matrix), TIMEOUT);
+    bool suspend_state = rgb_matrix_get_suspend_state();
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_RGB_SUSPEND_START, (void *)suspend_state, sizeof(i2c_buffer->rgb_suspend_state), TIMEOUT);
+#    endif
+
+#    ifndef DISABLE_SYNC_TIMER
+    i2c_buffer->sync_timer = sync_timer_read32() + SYNC_TIMER_OFFSET;
+    i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_SYNC_TIME_START, (void *)&i2c_buffer->sync_timer, sizeof(i2c_buffer->sync_timer), TIMEOUT);
 #    endif
 
     return true;
 }
 
-void transport_slave(matrix_row_t matrix[]) {
+void transport_slave(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
+#    ifndef DISABLE_SYNC_TIMER
+    sync_timer_update(i2c_buffer->sync_timer);
+#    endif
     // Copy matrix to I2C buffer
-    memcpy((void *)i2c_buffer->smatrix, (void *)matrix, sizeof(i2c_buffer->smatrix));
+    memcpy((void *)i2c_buffer->smatrix, (void *)slave_matrix, sizeof(i2c_buffer->smatrix));
+#    ifdef SPLIT_TRANSPORT_MIRROR
+    memcpy((void *)master_matrix, (void *)i2c_buffer->mmatrix, sizeof(i2c_buffer->mmatrix));
+#    endif
 
 // Read Backlight Info
 #    ifdef BACKLIGHT_ENABLE
@@ -235,6 +285,11 @@ void transport_slave(matrix_row_t matrix[]) {
 
 #    ifdef POINTING_DEVICE_ENABLE
     if (!is_keyboard_left()) {
+        static uint16_t cpi;
+        if (cpi != i2c_buffer->device_cpi) {
+            cpi = i2c_buffer->device_cpi;
+            pmw_set_cpi(cpi);
+        }
         i2c_buffer->mouse_x = split_mouse_x;
         i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_MOUSE_X_START, (void *)&i2c_buffer->mouse_x, sizeof(i2c_buffer->mouse_x), TIMEOUT);
         i2c_buffer->mouse_y = split_mouse_y;
@@ -266,8 +321,13 @@ void transport_slave(matrix_row_t matrix[]) {
     }
 #    endif
 
-#    ifdef RGB_MATRIX_ENABLE
-    rgb_matrix_set_suspend_state(i2c_buffer->is_rgb_matrix_suspended);
+#    if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+    memcpy((void *)i2c_buffer->led_matrix, (void *)led_matrix_eeconfig, sizeof(i2c_buffer->led_matrix));
+    led_matrix_set_suspend_state(i2c_buffer->led_suspend_state);
+#    endif
+#    if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+    memcpy((void *)i2c_buffer->rgb_matrix, (void *)rgb_matrix_config, sizeof(i2c_buffer->rgb_matrix));
+    rgb_matrix_set_suspend_state(i2c_buffer->rgb_suspend_state);
 #    endif
 }
 
@@ -283,30 +343,44 @@ typedef struct _Serial_s2m_buffer_t {
     // TODO: if MATRIX_COLS > 8 change to uint8_t packed_matrix[] for pack/unpack
     matrix_row_t smatrix[ROWS_PER_HAND];
 #    ifdef ENCODER_ENABLE
-    uint8_t encoder_state[NUMBER_OF_ENCODERS];
+    uint8_t      encoder_state[NUMBER_OF_ENCODERS];
 #    endif
-    int8_t mouse_x;
-    int8_t mouse_y;
+    int8_t       mouse_x;
+    int8_t       mouse_y;
 } __attribute__((packed)) Serial_s2m_buffer_t;
 
 typedef struct _Serial_m2s_buffer_t {
 #    ifdef SPLIT_MODS_ENABLE
-    uint8_t real_mods;
-    uint8_t weak_mods;
+    uint8_t       real_mods;
+    uint8_t       weak_mods;
 #        ifndef NO_ACTION_ONESHOT
-    uint8_t oneshot_mods;
+    uint8_t       oneshot_mods;
 #        endif
 #    endif
+#    ifndef DISABLE_SYNC_TIMER
+    uint32_t     sync_timer;
+#    endif
+#    ifdef SPLIT_TRANSPORT_MIRROR
+    matrix_row_t mmatrix[ROWS_PER_HAND];
+#    endif
 #    ifdef BACKLIGHT_ENABLE
-    uint8_t backlight_level;
+    uint8_t       backlight_level;
 #    endif
 #    ifdef WPM_ENABLE
-    uint8_t current_wpm;
+    uint8_t       current_wpm;
 #    endif
+    uint16_t      device_cpi;
     bool          oled_on;
     layer_state_t t_layer_state;
     layer_state_t t_default_layer_state;
-    bool          is_rgb_matrix_suspended;
+#    if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+    led_eeconfig_t led_matrix;
+    bool           led_suspend_state;
+#    endif
+#    if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+    rgb_config_t   rgb_matrix;
+    bool           rgb_suspend_state;
+#    endif
 } __attribute__((packed)) Serial_m2s_buffer_t;
 
 #    if defined(RGBLIGHT_ENABLE) && defined(RGBLIGHT_SPLIT)
@@ -383,7 +457,7 @@ void transport_rgblight_slave(void) {
 #        define transport_rgblight_slave()
 #    endif
 
-bool transport_master(matrix_row_t matrix[]) {
+bool transport_master(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
 #    ifndef SERIAL_USE_MULTI_TRANSACTION
     if (soft_serial_transaction() != TRANSACTION_END) {
         return false;
@@ -397,7 +471,10 @@ bool transport_master(matrix_row_t matrix[]) {
 
     // TODO:  if MATRIX_COLS > 8 change to unpack()
     for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        matrix[i] = serial_s2m_buffer.smatrix[i];
+        slave_matrix[i] = serial_s2m_buffer.smatrix[i];
+#    ifdef SPLIT_TRANSPORT_MIRROR
+        serial_m2s_buffer.mmatrix[i] = master_matrix[i];
+#    endif
     }
 
 #    ifdef BACKLIGHT_ENABLE
@@ -411,12 +488,12 @@ bool transport_master(matrix_row_t matrix[]) {
 
 #    ifdef WPM_ENABLE
     // Write wpm to slave
-    serial_m2s_buffer.current_wpm = get_current_wpm();
+    serial_m2s_buffer.current_wpm  = get_current_wpm();
 #    endif
 
 #    ifdef SPLIT_MODS_ENABLE
-    serial_m2s_buffer.real_mods = get_mods();
-    serial_m2s_buffer.weak_mods = get_weak_mods();
+    serial_m2s_buffer.real_mods    = get_mods();
+    serial_m2s_buffer.weak_mods    = get_weak_mods();
 #        ifndef NO_ACTION_ONESHOT
     serial_m2s_buffer.oneshot_mods = get_oneshot_mods();
 #        endif
@@ -428,28 +505,43 @@ bool transport_master(matrix_row_t matrix[]) {
         temp_report.x              = serial_s2m_buffer.mouse_x;
         temp_report.y              = serial_s2m_buffer.mouse_y;
         pointing_device_set_report(temp_report);
+        serial_m2s_buffer.device_cpi = device_cpi;
     }
 #    endif
 
-    serial_m2s_buffer.t_layer_state         = layer_state;
-    serial_m2s_buffer.t_default_layer_state = default_layer_state;
+    serial_m2s_buffer.t_layer_state           = layer_state;
+    serial_m2s_buffer.t_default_layer_state   = default_layer_state;
 #    ifdef OLED_DRIVER_ENABLE
-    serial_m2s_buffer.oled_on = is_oled_on();
+    serial_m2s_buffer.oled_on                 = is_oled_on();
 #    endif
 
-#    ifdef RGB_MATRIX_ENABLE
-    serial_m2s_buffer.is_rgb_matrix_suspended = rgb_matrix_get_suspend_state();
+#    if defined(LED_MATRIX_ENABLE) && defined(LED_MATRIX_SPLIT)
+    serial_m2s_buffer.led_matrix        = led_matrix_eeconfig;
+    serial_m2s_buffer.led_suspend_state = led_matrix_get_suspend_state();
+#    endif
+#    if defined(RGB_MATRIX_ENABLE) && defined(RGB_MATRIX_SPLIT)
+    serial_m2s_buffer.rgb_matrix        = rgb_matrix_config;
+    serial_m2s_buffer.rgb_suspend_state = rgb_matrix_get_suspend_state();
 #    endif
 
+#    ifndef DISABLE_SYNC_TIMER
+    serial_m2s_buffer.sync_timer   = sync_timer_read32() + SYNC_TIMER_OFFSET;
+#    endif
     return true;
 }
 
-void transport_slave(matrix_row_t matrix[]) {
+void transport_slave(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
     transport_rgblight_slave();
+#    ifndef DISABLE_SYNC_TIMER
+    sync_timer_update(serial_m2s_buffer.sync_timer);
+#    endif
 
     // TODO: if MATRIX_COLS > 8 change to pack()