14 files changed, 394 insertions, 244 deletions

diff --git a/tmk_core/common/action.c b/tmk_core/common/action.c
index a7432bae5..a3830abbf 100644
--- a/tmk_core/common/action.c
+++ b/tmk_core/common/action.c
@@ -443,6 +443,15 @@ void process_action(keyrecord_t *record, action_t action) {
                     case KC_MS_BTN5:
                         register_button(true, MOUSE_BTN5);
                         break;
+                    case KC_MS_BTN6:
+                        register_button(true, MOUSE_BTN6);
+                        break;
+                    case KC_MS_BTN7:
+                        register_button(true, MOUSE_BTN7);
+                        break;
+                    case KC_MS_BTN8:
+                        register_button(true, MOUSE_BTN8);
+                        break;
 #    endif
                     default:
                         mousekey_send();
@@ -469,6 +478,15 @@ void process_action(keyrecord_t *record, action_t action) {
                     case KC_MS_BTN5:
                         register_button(false, MOUSE_BTN5);
                         break;
+                    case KC_MS_BTN6:
+                        register_button(false, MOUSE_BTN6);
+                        break;
+                    case KC_MS_BTN7:
+                        register_button(false, MOUSE_BTN7);
+                        break;
+                    case KC_MS_BTN8:
+                        register_button(false, MOUSE_BTN8);
+                        break;
 #    endif
                     default:
                         mousekey_send();
diff --git a/tmk_core/common/avr/bootloader.c b/tmk_core/common/avr/bootloader.c
index a1db55da9..4e3a27022 100644
--- a/tmk_core/common/avr/bootloader.c
+++ b/tmk_core/common/avr/bootloader.c
@@ -77,7 +77,7 @@ uint32_t reset_key __attribute__((section(".noinit,\"aw\",@nobits;")));
  *
  * FIXME: needs doc
  */
-void bootloader_jump(void) {
+__attribute__((weak)) void bootloader_jump(void) {
 #if !defined(BOOTLOADER_SIZE)
     uint8_t high_fuse = boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS);
 
@@ -237,13 +237,13 @@ void bootloader_jump(void) {
                  "bootloader_startup_loop%=:         \n\t"
                  "rjmp bootloader_startup_loop%=     \n\t"
                  :
-                 : [mcucsrio] "I"(_SFR_IO_ADDR(MCUCSR)),
+                 : [ mcucsrio ] "I"(_SFR_IO_ADDR(MCUCSR)),
 #    if (FLASHEND > 131071)
-                   [ramendhi] "M"(((RAMEND - 2) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 2) >> 0) & 0xff), [bootaddrhi] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
+                   [ ramendhi ] "M"(((RAMEND - 2) >> 8) & 0xff), [ ramendlo ] "M"(((RAMEND - 2) >> 0) & 0xff), [ bootaddrhi ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
 #    else
-                   [ramendhi] "M"(((RAMEND - 1) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 1) >> 0) & 0xff),
+                   [ ramendhi ] "M"(((RAMEND - 1) >> 8) & 0xff), [ ramendlo ] "M"(((RAMEND - 1) >> 0) & 0xff),
 #    endif
-                   [bootaddrme] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [bootaddrlo] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
+                   [ bootaddrme ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [ bootaddrlo ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
 
 #else  // Assume remaining boards are DFU, even if the flag isn't set
 
diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index b35620e7f..1250c45ae 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -23,6 +23,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "led.h"
 #include "keycode.h"
 #include "timer.h"
+#include "sync_timer.h"
 #include "print.h"
 #include "debug.h"
 #include "command.h"
@@ -96,6 +97,20 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #    include "dip_switch.h"
 #endif
 
+static uint32_t last_input_modification_time = 0;
+uint32_t        last_input_activity_time(void) { return last_input_modification_time; }
+uint32_t        last_input_activity_elapsed(void) { return timer_elapsed32(last_input_modification_time); }
+
+static uint32_t last_matrix_modification_time = 0;
+uint32_t        last_matrix_activity_time(void) { return last_matrix_modification_time; }
+uint32_t        last_matrix_activity_elapsed(void) { return timer_elapsed32(last_matrix_modification_time); }
+void            last_matrix_activity_trigger(void) { last_matrix_modification_time = last_input_modification_time = timer_read32(); }
+
+static uint32_t last_encoder_modification_time = 0;
+uint32_t        last_encoder_activity_time(void) { return last_encoder_modification_time; }
+uint32_t        last_encoder_activity_elapsed(void) { return timer_elapsed32(last_encoder_modification_time); }
+void            last_encoder_activity_trigger(void) { last_encoder_modification_time = last_input_modification_time = timer_read32(); }
+
 // Only enable this if console is enabled to print to
 #if defined(DEBUG_MATRIX_SCAN_RATE)
 static uint32_t matrix_timer      = 0;
@@ -262,6 +277,7 @@ __attribute__((weak)) void housekeeping_task_user(void) {}
  */
 void keyboard_init(void) {
     timer_init();
+    sync_timer_init();
     matrix_init();
 #ifdef VIA_ENABLE
     via_init();
@@ -339,15 +355,15 @@ void keyboard_task(void) {
 #ifdef QMK_KEYS_PER_SCAN
     uint8_t keys_processed = 0;
 #endif
+#ifdef ENCODER_ENABLE
+    bool encoders_changed = false;
+#endif
 
     housekeeping_task_kb();
     housekeeping_task_user();
 
-#if defined(OLED_DRIVER_ENABLE) && !defined(OLED_DISABLE_TIMEOUT)
-    uint8_t ret = matrix_scan();
-#else
-    matrix_scan();
-#endif
+    uint8_t matrix_changed = matrix_scan();
+    if (matrix_changed) last_matrix_activity_trigger();
 
     if (should_process_keypress()) {
         for (uint8_t r = 0; r < MATRIX_ROWS; r++) {
@@ -403,7 +419,8 @@ MATRIX_LOOP_END:
 #endif
 
 #ifdef ENCODER_ENABLE
-    encoder_read();
+    encoders_changed = encoder_read();
+    if (encoders_changed) last_encoder_activity_trigger();
 #endif
 
 #ifdef QWIIC_ENABLE
@@ -413,8 +430,12 @@ MATRIX_LOOP_END:
 #ifdef OLED_DRIVER_ENABLE
     oled_task();
 #    ifndef OLED_DISABLE_TIMEOUT
-    // Wake up oled if user is using those fabulous keys!
-    if (ret) oled_on();
+    // Wake up oled if user is using those fabulous keys or spinning those encoders!
+#        ifdef ENCODER_ENABLE
+    if (matrix_changed || encoders_changed) oled_on();
+#        else
+    if (matrix_changed) oled_on();
+#        endif
 #    endif
 #endif
 
diff --git a/tmk_core/common/keyboard.h b/tmk_core/common/keyboard.h
index 70e8f7e2c..eaf74bac5 100644
--- a/tmk_core/common/keyboard.h
+++ b/tmk_core/common/keyboard.h
@@ -73,6 +73,15 @@ void keyboard_post_init_user(void);
 void housekeeping_task_kb(void);
 void housekeeping_task_user(void);
 
+uint32_t last_input_activity_time(void);     // Timestamp of the last matrix or encoder activity
+uint32_t last_input_activity_elapsed(void);  // Number of milliseconds since the last matrix or encoder activity
+
+uint32_t last_matrix_activity_time(void);     // Timestamp of the last matrix activity
+uint32_t last_matrix_activity_elapsed(void);  // Number of milliseconds since the last matrix activity
+
+uint32_t last_encoder_activity_time(void);     // Timestamp of the last encoder activity
+uint32_t last_encoder_activity_elapsed(void);  // Number of milliseconds since the last encoder activity
+
 uint32_t get_matrix_scan_rate(void);
 
 #ifdef __cplusplus
diff --git a/tmk_core/common/keycode.h b/tmk_core/common/keycode.h
index d35e44d8d..efad92b23 100644
--- a/tmk_core/common/keycode.h
+++ b/tmk_core/common/keycode.h
@@ -39,7 +39,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #define IS_MOUSEKEY(code) (KC_MS_UP <= (code) && (code) <= KC_MS_ACCEL2)
 #define IS_MOUSEKEY_MOVE(code) (KC_MS_UP <= (code) && (code) <= KC_MS_RIGHT)
-#define IS_MOUSEKEY_BUTTON(code) (KC_MS_BTN1 <= (code) && (code) <= KC_MS_BTN5)
+#define IS_MOUSEKEY_BUTTON(code) (KC_MS_BTN1 <= (code) && (code) <= KC_MS_BTN8)
 #define IS_MOUSEKEY_WHEEL(code) (KC_MS_WH_UP <= (code) && (code) <= KC_MS_WH_RIGHT)
 #define IS_MOUSEKEY_ACCEL(code) (KC_MS_ACCEL0 <= (code) && (code) <= KC_MS_ACCEL2)
 
@@ -205,6 +205,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define KC_BTN3 KC_MS_BTN3
 #define KC_BTN4 KC_MS_BTN4
 #define KC_BTN5 KC_MS_BTN5
+#define KC_BTN6 KC_MS_BTN6
+#define KC_BTN7 KC_MS_BTN7
+#define KC_BTN8 KC_MS_BTN8
 #define KC_WH_U KC_MS_WH_UP
 #define KC_WH_D KC_MS_WH_DOWN
 #define KC_WH_L KC_MS_WH_LEFT
@@ -521,15 +524,18 @@ enum internal_special_keycodes {
 
 enum mouse_keys {
     /* Mouse Buttons */
-    KC_MS_UP = 0xF0,
+    KC_MS_UP = 0xED,
     KC_MS_DOWN,
     KC_MS_LEFT,
-    KC_MS_RIGHT,
+    KC_MS_RIGHT,  // 0xF0
     KC_MS_BTN1,
     KC_MS_BTN2,
     KC_MS_BTN3,
     KC_MS_BTN4,
     KC_MS_BTN5,
+    KC_MS_BTN6,
+    KC_MS_BTN7,
+    KC_MS_BTN8,
 
     /* Mouse Wheel */
     KC_MS_WH_UP,
@@ -540,5 +546,5 @@ enum mouse_keys {
     /* Acceleration */
     KC_MS_ACCEL0,
     KC_MS_ACCEL1,
-    KC_MS_ACCEL2
+    KC_MS_ACCEL2  // 0xFF
 };
diff --git a/tmk_core/common/matrix.h b/tmk_core/common/matrix.h
index b570227a3..ce57010a4 100644
--- a/tmk_core/common/matrix.h
+++ b/tmk_core/common/matrix.h
@@ -55,6 +55,9 @@ matrix_row_t matrix_get_row(uint8_t row);
 /* print matrix for debug */
 void matrix_print(void);
 /* delay between changing matrix pin state and reading values */
+void matrix_output_select_delay(void);
+void matrix_output_unselect_delay(void);
+/* only for backwards compatibility. delay between changing matrix pin state and reading values */
 void matrix_io_delay(void);
 
 /* power control */
diff --git a/tmk_core/common/mousekey.c b/tmk_core/common/mousekey.c
index ef18bcf1a..d8cf63f77 100644
--- a/tmk_core/common/mousekey.c
+++ b/tmk_core/common/mousekey.c
@@ -36,6 +36,9 @@ static void           mousekey_debug(void);
 static uint8_t        mousekey_accel        = 0;
 static uint8_t        mousekey_repeat       = 0;
 static uint8_t        mousekey_wheel_repeat = 0;
+#ifdef MK_KINETIC_SPEED
+static uint16_t mouse_timer = 0;
+#endif
 
 #ifndef MK_3_SPEED
 
@@ -43,7 +46,7 @@ static uint16_t last_timer_c = 0;
 static uint16_t last_timer_w = 0;
 
 /*
- * Mouse keys  acceleration algorithm
+ * Mouse keys acceleration algorithm
  *  http://en.wikipedia.org/wiki/Mouse_keys
  *
  *  speed = delta * max_speed * (repeat / time_to_max)**((1000+curve)/1000)
@@ -105,6 +108,65 @@ static uint8_t wheel_unit(void) {
 }
 
 #    else /* #ifndef MK_COMBINED */
+#        ifndef MK_KINETIC_SPEED
+
+/*
+ * Kinetic movement  acceleration algorithm
+ *
+ *  current speed = I + A * T/50 + A * 0.5 * T^2 | maximum B
+ *
+ * T: time since the mouse movement started
+ * E: mouse events per second (set through MOUSEKEY_INTERVAL, UHK sends 250, the
+ *    pro micro on my Signum 3.0 sends only 125!)
+ * I: initial speed at time 0
+ * A: acceleration
+ * B: base mouse travel speed
+ */
+const uint16_t mk_accelerated_speed = MOUSEKEY_ACCELERATED_SPEED;
+const uint16_t mk_base_speed        = MOUSEKEY_BASE_SPEED;
+const uint16_t mk_decelerated_speed = MOUSEKEY_DECELERATED_SPEED;
+const uint16_t mk_initial_speed     = MOUSEKEY_INITIAL_SPEED;
+
+static uint8_t move_unit(void) {
+    float speed = mk_initial_speed;
+
+    if (mousekey_accel & ((1 << 0) | (1 << 2))) {
+        speed = mousekey_accel & (1 << 2) ? mk_accelerated_speed : mk_decelerated_speed;
+    } else if (mousekey_repeat && mouse_timer) {
+        const float time_elapsed = timer_elapsed(mouse_timer) / 50;
+        speed                    = mk_initial_speed + MOUSEKEY_MOVE_DELTA * time_elapsed + MOUSEKEY_MOVE_DELTA * 0.5 * time_elapsed * time_elapsed;
+
+        speed = speed > mk_base_speed ? mk_base_speed : speed;
+    }
+
+    /* convert speed to USB mouse speed 1 to 127 */
+    speed = (uint8_t)(speed / (1000.0f / mk_interval));
+    speed = speed < 1 ? 1 : speed;
+
+    return speed > MOUSEKEY_MOVE_MAX ? MOUSEKEY_MOVE_MAX : speed;
+}
+
+float mk_wheel_interval = 1000.0f / MOUSEKEY_WHEEL_INITIAL_MOVEMENTS;
+
+static uint8_t wheel_unit(void) {
+    float speed = MOUSEKEY_WHEEL_INITIAL_MOVEMENTS;
+
+    if (mousekey_accel & ((1 << 0) | (1 << 2))) {
+        speed = mousekey_accel & (1 << 2) ? MOUSEKEY_WHEEL_ACCELERATED_MOVEMENTS : MOUSEKEY_WHEEL_DECELERATED_MOVEMENTS;
+    } else if (mousekey_repeat && mouse_timer) {
+        if (mk_wheel_interval != MOUSEKEY_WHEEL_BASE_MOVEMENTS) {
+            const float time_elapsed = timer_elapsed(mouse_timer) / 50;
+            speed                    = MOUSEKEY_WHEEL_INITIAL_MOVEMENTS + 1 * time_elapsed + 1 * 0.5 * time_elapsed * time_elapsed;
+        }
+        speed = speed > MOUSEKEY_WHEEL_BASE_MOVEMENTS ? MOUSEKEY_WHEEL_BASE_MOVEMENTS : speed;
+    }
+
+    mk_wheel_interval = 1000.0f / speed;
+
+    return 1;
+}
+
+#        else /* #ifndef MK_KINETIC_SPEED */
 
 static uint8_t move_unit(void) {
     uint16_t unit;
@@ -142,7 +204,8 @@ static uint8_t wheel_unit(void) {
     return (unit > MOUSEKEY_WHEEL_MAX ? MOUSEKEY_WHEEL_MAX : (unit == 0 ? 1 : unit));
 }
 
-#    endif /* #ifndef MK_COMBINED */
+#        endif /* #ifndef MK_KINETIC_SPEED */
+#    endif     /* #ifndef MK_COMBINED */
 
 void mousekey_task(void) {
     // report cursor and scroll movement independently
@@ -193,6 +256,12 @@ void mousekey_task(void) {
 }
 
 void mousekey_on(uint8_t code) {
+#    ifdef MK_KINETIC_SPEED
+    if (mouse_timer == 0) {
+        mouse_timer = timer_read();
+    }
+#    endif /* #ifdef MK_KINETIC_SPEED */
+
     if (code == KC_MS_UP)
         mouse_report.y = move_unit() * -1;
     else if (code == KC_MS_DOWN)
@@ -209,16 +278,8 @@ void mousekey_on(uint8_t code) {
         mouse_report.h = wheel_unit() * -1;
     else if (code == KC_MS_WH_RIGHT)
         mouse_report.h = wheel_unit();
-    else if (code == KC_MS_BTN1)
-        mouse_report.buttons |= MOUSE_BTN1;
-    else if (code == KC_MS_BTN2)
-        mouse_report.buttons |= MOUSE_BTN2;
-    else if (code == KC_MS_BTN3)
-        mouse_report.buttons |= MOUSE_BTN3;
-    else if (code == KC_MS_BTN4)
-        mouse_report.buttons |= MOUSE_BTN4;
-    else if (code == KC_MS_BTN5)
-        mouse_report.buttons |= MOUSE_BTN5;
+    else if (IS_MOUSEKEY_BUTTON(code))
+        mouse_report.buttons |= 1 << (code - KC_MS_BTN1);
     else if (code == KC_MS_ACCEL0)
         mousekey_accel |= (1 << 0);
     else if (code == KC_MS_ACCEL1)
@@ -244,23 +305,20 @@ void mousekey_off(uint8_t code) {
         mouse_report.h = 0;
     else if (code == KC_MS_WH_RIGHT && mouse_report.h > 0)
         mouse_report.h = 0;
-    else if (code == KC_MS_BTN1)
-        mouse_report.buttons &= ~MOUSE_BTN1;
-    else if (code == KC_MS_BTN2)
-        mouse_report.buttons &= ~MOUSE_BTN2;
-    else if (code == KC_MS_BTN3)
-        mouse_report.buttons &= ~MOUSE_BTN3;
-    else if (code == KC_MS_BTN4)
-        mouse_report.buttons &= ~MOUSE_BTN4;
-    else if (code == KC_MS_BTN5)
-        mouse_report.buttons &= ~MOUSE_BTN5;
+    else if (IS_MOUSEKEY_BUTTON(code))
+        mouse_report.buttons &= ~(1 << (code - KC_MS_BTN1));
     else if (code == KC_MS_ACCEL0)
         mousekey_accel &= ~(1 << 0);
     else if (code == KC_MS_ACCEL1)
         mousekey_accel &= ~(1 << 1);
     else if (code == KC_MS_ACCEL2)
         mousekey_accel &= ~(1 << 2);
-    if (mouse_report.x == 0 && mouse_report.y == 0) mousekey_repeat = 0;
+    if (mouse_report.x == 0 && mouse_report.y == 0) {
+        mousekey_repeat = 0;
+#    ifdef MK_KINETIC_SPEED
+        mouse_timer = 0;
+#    endif /* #ifdef MK_KINETIC_SPEED */
+    }
     if (mouse_report.v == 0 && mouse_report.h == 0) mousekey_wheel_repeat = 0;
 }
 
@@ -349,16 +407,8 @@ void mousekey_on(uint8_t code) {
         mouse_report.h = w_offset * -1;
     else if (code == KC_MS_WH_RIGHT)
         mouse_report.h = w_offset;
-    else if (code == KC_MS_BTN1)
-        mouse_report.buttons |= MOUSE_BTN1;
-    else if (code == KC_MS_BTN2)
-        mouse_report.buttons |= MOUSE_BTN2;
-    else if (code == KC_MS_BTN3)
-        mouse_report.buttons |= MOUSE_BTN3;
-    else if (code == KC_MS_BTN4)
-        mouse_report.buttons |= MOUSE_BTN4;
-    else if (code == KC_MS_BTN5)
-        mouse_report.buttons |= MOUSE_BTN5;
+    else if (IS_MOUSEKEY_BUTTON(code))
+        mouse_report.buttons |= 1 << (code - KC_MS_BTN1);
     else if (code == KC_MS_ACCEL0)
         mk_speed = mkspd_0;
     else if (code == KC_MS_ACCEL1)
@@ -388,16 +438,8 @@ void mousekey_off(uint8_t code) {
         mouse_report.h = 0;
     else if (code == KC_MS_WH_RIGHT && mouse_report.h > 0)
         mouse_report.h = 0;
-    else if (code == KC_MS_BTN1)
-        mouse_report.buttons &= ~MOUSE_BTN1;
-    else if (code == KC_MS_BTN2)
-        mouse_report.buttons &= ~MOUSE_BTN2;
-    else if (code == KC_MS_BTN3)
-        mouse_report.buttons &= ~MOUSE_BTN3;
-    else if (code == KC_MS_BTN4)
-        mouse_report.buttons &= ~MOUSE_BTN4;
-    else if (code == KC_MS_BTN5)
-        mouse_report.buttons &= ~MOUSE_BTN5;
+    else if (IS_MOUSEKEY_BUTTON(code))
+        mouse_report.buttons &= ~(1 << (code - KC_MS_BTN1));
 #    ifdef MK_MOMENTARY_ACCEL
     else if (code == KC_MS_ACCEL0)
         mk_speed = mkspd_DEFAULT;
diff --git a/tmk_core/common/mousekey.h b/tmk_core/common/mousekey.h
index 300d262f5..52b8fe10e 100644
--- a/tmk_core/common/mousekey.h
+++ b/tmk_core/common/mousekey.h
@@ -36,16 +36,28 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #    endif
 
 #    ifndef MOUSEKEY_MOVE_DELTA
-#        define MOUSEKEY_MOVE_DELTA 5
+#        ifndef MK_KINETIC_SPEED
+#            define MOUSEKEY_MOVE_DELTA 5
+#        else
+#            define MOUSEKEY_MOVE_DELTA 25
+#        endif
 #    endif
 #    ifndef MOUSEKEY_WHEEL_DELTA
 #        define MOUSEKEY_WHEEL_DELTA 1
 #    endif
 #    ifndef MOUSEKEY_DELAY
-#        define MOUSEKEY_DELAY 300
+#        ifndef MK_KINETIC_SPEED
+#            define MOUSEKEY_DELAY 300
+#        else
+#            define MOUSEKEY_DELAY 8
+#        endif
 #    endif
 #    ifndef MOUSEKEY_INTERVAL
-#        define MOUSEKEY_INTERVAL 50
+#        ifndef MK_KINETIC_SPEED
+#            define MOUSEKEY_INTERVAL 50
+#        else
+#            define MOUSEKEY_INTERVAL 8
+#        endif
 #    endif
 #    ifndef MOUSEKEY_MAX_SPEED
 #        define MOUSEKEY_MAX_SPEED 10
@@ -66,6 +78,31 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #        define MOUSEKEY_WHEEL_TIME_TO_MAX 40
 #    endif
 
+#    ifndef MOUSEKEY_INITIAL_SPEED
+#        define MOUSEKEY_INITIAL_SPEED 100
+#    endif
+#    ifndef MOUSEKEY_BASE_SPEED
+#        define MOUSEKEY_BASE_SPEED 1000
+#    endif
+#    ifndef MOUSEKEY_DECELERATED_SPEED
+#        define MOUSEKEY_DECELERATED_SPEED 400
+#    endif
+#    ifndef MOUSEKEY_ACCELERATED_SPEED
+#        define MOUSEKEY_ACCELERATED_SPEED 3000
+#    endif
+#    ifndef MOUSEKEY_WHEEL_INITIAL_MOVEMENTS
+#        define MOUSEKEY_WHEEL_INITIAL_MOVEMENTS 16
+#    endif
+#    ifndef MOUSEKEY_WHEEL_BASE_MOVEMENTS
+#        define MOUSEKEY_WHEEL_BASE_MOVEMENTS 32
+#    endif
+#    ifndef MOUSEKEY_WHEEL_ACCELERATED_MOVEMENTS
+#        define MOUSEKEY_WHEEL_ACCELERATED_MOVEMENTS 48
+#    endif
+#    ifndef MOUSEKEY_WHEEL_DECELERATED_MOVEMENTS
+#        define MOUSEKEY_WHEEL_DECELERATED_MOVEMENTS 8
+#    endif
+
 #else /* #ifndef MK_3_SPEED */
 
 #    ifndef MK_C_OFFSET_UNMOD
diff --git a/tmk_core/common/report.h b/tmk_core/common/report.h
index 5d7c5b3b2..bcf5cab38 100644
--- a/tmk_core/common/report.h
+++ b/tmk_core/common/report.h
@@ -39,7 +39,10 @@ enum mouse_buttons {
     MOUSE_BTN2 = (1 << 1),
     MOUSE_BTN3 = (1 << 2),
     MOUSE_BTN4 = (1 << 3),
-    MOUSE_BTN5 = (1 << 4)
+    MOUSE_BTN5 = (1 << 4),
+    MOUSE_BTN6 = (1 << 5),
+    MOUSE_BTN7 = (1 << 6),
+    MOUSE_BTN8 = (1 << 7)
 };
 
 /* Consumer Page (0x0C)
diff --git a/tmk_core/common/sync_timer.c b/tmk_core/common/sync_timer.c
new file mode 100644
index 000000000..de24b463b
--- /dev/null
+++ b/tmk_core/common/sync_timer.c
@@ -0,0 +1,58 @@
+/*
+Copyright (C) 2020 Ryan Caltabiano <https://github.com/XScorpion2>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+If you happen to meet one of the copyright holders in a bar you are obligated
+to buy them one pint of beer.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include "sync_timer.h"
+#include "keyboard.h"
+
+#if defined(SPLIT_KEYBOARD) && !defined(DISABLE_SYNC_TIMER)
+volatile int32_t sync_timer_ms;
+
+void sync_timer_init(void) { sync_timer_ms = 0; }
+
+void sync_timer_update(uint32_t time) {
+    if (is_keyboard_master()) return;
+    sync_timer_ms = time - timer_read32();
+}
+
+uint16_t sync_timer_read(void) {
+    if (is_keyboard_master()) return timer_read();
+    return sync_timer_read32();
+}
+
+uint32_t sync_timer_read32(void) {
+    if (is_keyboard_master()) return timer_read32();
+    return sync_timer_ms + timer_read32();
+}
+
+uint16_t sync_timer_elapsed(uint16_t last) {
+    if (is_keyboard_master()) return timer_elapsed(last);
+    return TIMER_DIFF_16(sync_timer_read(), last);
+}
+
+uint32_t sync_timer_elapsed32(uint32_t last) {
+    if (is_keyboard_master()) return timer_elapsed32(last);
+    return TIMER_DIFF_32(sync_timer_read32(), last);
+}
+#endif
diff --git a/tmk_core/common/sync_timer.h b/tmk_core/common/sync_timer.h
new file mode 100644
index 000000000..9ddef45bb
--- /dev/null
+++ b/tmk_core/common/sync_timer.h
@@ -0,0 +1,54 @@
+/*
+Copyright (C) 2020 Ryan Caltabiano <https://github.com/XScorpion2>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+If you happen to meet one of the copyright holders in a bar you are obligated
+to buy them one pint of beer.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#pragma once
+
+#include <stdint.h>
+#include "timer.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(SPLIT_KEYBOARD) && !defined(DISABLE_SYNC_TIMER)
+void     sync_timer_init(void);
+void     sync_timer_update(uint32_t time);
+uint16_t sync_timer_read(void);
+uint32_t sync_timer_read32(void);
+uint16_t sync_timer_elapsed(uint16_t last);
+uint32_t sync_timer_elapsed32(uint32_t last);
+#else
+#    define sync_timer_init()
+#    define sync_timer_clear()
+#    define sync_timer_update(t)
+#    define sync_timer_read() timer_read()
+#    define sync_timer_read32() timer_read32()
+#    define sync_timer_elapsed(t) timer_elapsed(t)
+#    define sync_timer_elapsed32(t) timer_elapsed32(t)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/tmk_core/common/uart.c b/tmk_core/common/uart.c
deleted file mode 100644
index 150e256c8..000000000
--- a/tmk_core/common/uart.c
+++ /dev/null
@@ -1,172 +0,0 @@
-// TODO: Teensy support(ATMega32u4/AT90USB128)
-// Fixed for Arduino Duemilanove ATmega168p by Jun Wako
-/* UART Example for Teensy USB Development Board
- * http://www.pjrc.com/teensy/
- * Copyright (c) 2009 PJRC.COM, LLC
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-// Version 1.0: Initial Release
-// Version 1.1: Add support for Teensy 2.0, minor optimizations
-
-#include <avr/io.h>
-#include <avr/interrupt.h>
-
-#include "uart.h"
-
-#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)
-#    define UDRn UDR0
-#    define UBRRnL UBRR0L
-#    define UCSRnA UCSR0A
-#    define UCSRnB UCSR0B
-#    define UCSRnC UCSR0C
-#    define U2Xn U2X0
-#    define RXENn RXEN0
-#    define TXENn TXEN0
-#    define RXCIEn RXCIE0
-#    define UCSZn1 UCSZ01
-#    define UCSZn0 UCSZ00
-#    define UDRIEn UDRIE0
-#    define USARTn_UDRE_vect USART_UDRE_vect
-#    define USARTn_RX_vect USART_RX_vect
-#elif defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega32U2__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
-#    define UDRn UDR1
-#    define UBRRnL UBRR1L
-#    define UCSRnA UCSR1A
-#    define UCSRnB UCSR1B
-#    define UCSRnC UCSR1C
-#    define U2Xn U2X1
-#    define RXENn RXEN1
-#    define TXENn TXEN1
-#    define RXCIEn RXCIE1
-#    define UCSZn1 UCSZ11
-#    define UCSZn0 UCSZ10
-#    define UDRIEn UDRIE1
-#    define USARTn_UDRE_vect USART1_UDRE_vect
-#    define USARTn_RX_vect USART1_RX_vect
-#elif defined(__AVR_ATmega32A__)
-#    define UDRn UDR
-#    define UBRRnL UBRRL
-#    define UCSRnA UCSRA
-#    define UCSRnB UCSRB
-#    define UCSRnC UCSRC
-#    define U2Xn U2X
-#    define RXENn RXEN
-#    define TXENn TXEN
-#    define RXCIEn RXCIE
-#    define UCSZn1 UCSZ1
-#    define UCSZn0 UCSZ0
-#    define UDRIEn UDRIE
-#    define USARTn_UDRE_vect USART_UDRE_vect
-#    define USARTn_RX_vect USART_RX_vect
-#endif
-
-// These buffers may be any size from 2 to 256 bytes.
-#define RX_BUFFER_SIZE 64
-#define TX_BUFFER_SIZE 256
-
-static volatile uint8_t tx_buffer[TX_BUFFER_SIZE];
-static volatile uint8_t tx_buffer_head;
-static volatile uint8_t tx_buffer_tail;
-static volatile uint8_t rx_buffer[RX_BUFFER_SIZE];
-static volatile uint8_t rx_buffer_head;
-static volatile uint8_t rx_buffer_tail;
-
-// Initialize the UART
-void uart_init(uint32_t baud) {
-    cli();
-    UBRRnL         = (F_CPU / 4 / baud - 1) / 2;
-    UCSRnA         = (1 << U2Xn);
-    UCSRnB         = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn);
-    UCSRnC         = (1 << UCSZn1) | (1 << UCSZn0);
-    tx_buffer_head = tx_buffer_tail = 0;
-    rx_buffer_head = rx_buffer_tail = 0;
-    sei();
-}
-
-// Transmit a byte
-void uart_putchar(uint8_t c) {
-    uint8_t i;
-
-    i = tx_buffer_head + 1;
-    if (i >= TX_BUFFER_SIZE) i = 0;
-    // return immediately to avoid deadlock when interrupt is disabled(called from ISR)
-    if (tx_buffer_tail == i && (SREG & (1 << SREG_I)) == 0) return;
-    while (tx_buffer_tail == i)
-        ;  // wait until space in buffer
-    // cli();
-    tx_buffer[i]   = c;
-    tx_buffer_head = i;
-    UCSRnB         = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn) | (1 << UDRIEn);
-    // sei();
-}
-
-// Receive a byte
-uint8_t uart_getchar(void) {
-    uint8_t c, i;
-
-    while (rx_buffer_head == rx_buffer_tail)
-        ;  // wait for character
-    i = rx_buffer_tail + 1;
-    if (i >= RX_BUFFER_SIZE) i = 0;
-    c              = rx_buffer[i];
-    rx_buffer_tail = i;
-    return c;
-}
-
-// Return the number of bytes waiting in the receive buffer.
-// Call this before uart_getchar() to check if it will need
-// to wait for a byte to arrive.
-uint8_t uart_available(void) {
-    uint8_t head, tail;
-
-    head = rx_buffer_head;
-    tail = rx_buffer_tail;
-    if (head >= tail) return head - tail;
-    return RX_BUFFER_SIZE + head - tail;
-}
-
-// Transmit Interrupt
-ISR(USARTn_UDRE_vect) {
-    uint8_t i;
-
-    if (tx_buffer_head == tx_buffer_tail) {
-        // buffer is empty, disable transmit interrupt
-        UCSRnB = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn);
-    } else {
-        i = tx_buffer_tail + 1;
-        if (i >= TX_BUFFER_SIZE) i = 0;
-        UDRn           = tx_buffer[i];
-        tx_buffer_tail = i;
-    }
-}
-
-// Receive Interrupt
-ISR(USARTn_RX_vect) {
-    uint8_t c, i;
-
-    c = UDRn;
-    i = rx_buffer_head + 1;
-    if (i >= RX_BUFFER_SIZE) i = 0;
-    if (i != rx_buffer_tail) {
-        rx_buffer[i]   = c;
-        rx_buffer_head = i;
-    }
-}
diff --git a/tmk_core/common/uart.h b/tmk_core/common/uart.h
deleted file mode 100644
index ea247b17b..000000000
--- a/tmk_core/common/uart.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#pragma once
-
-#include <stdint.h>
-
-void    uart_init(uint32_t baud);
-void    uart_putchar(uint8_t c);
-uint8_t uart_getchar(void);
-uint8_t uart_available(void);
diff --git a/tmk_core/common/wait.h b/tmk_core/common/wait.h
index 89128e9da..28224fe3a 100644
--- a/tmk_core/common/wait.h
+++ b/tmk_core/common/wait.h
@@ -6,10 +6,89 @@
 extern "C" {
 #endif
 
+#if defined(__ARMEL__) || defined(__ARMEB__)
+#    ifndef __OPTIMIZE__
+#        pragma message "Compiler optimizations disabled; wait_cpuclock() won't work as designed"
+#    endif
+
+#    define wait_cpuclock(x) wait_cpuclock_allnop(x)
+
+#    define CLOCK_DELAY_NOP8 "nop\n\t nop\n\t nop\n\t nop\n\t   nop\n\t nop\n\t nop\n\t nop\n\t"
+
+__attribute__((always_inline)) static inline void wait_cpuclock_allnop(unsigned int n) { /* n: 1..135 */
+    /* The argument n must be a constant expression.
+     * That way, compiler optimization will remove unnecessary code. */
+    if (n < 1) {
+        return;
+    }
+    if (n > 8) {
+        unsigned int n8 = n / 8;
+        n               = n - n8 * 8;
+        switch (n8) {
+            case 16:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 15:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 14:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 13:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 12:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 11:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 10:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 9:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 8:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 7:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 6:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 5:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 4:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 3:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 2:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 1:
+                asm volatile(CLOCK_DELAY_NOP8::: "memory");
+            case 0:
+                break;
+        }
+    }
+    switch (n) {
+        case 8:
+            asm volatile("nop" ::: "memory");
+        case 7:
+            asm volatile("nop" ::: "memory");
+        case 6:
+            asm volatile("nop" ::: "memory");
+        case 5:
+            asm volatile("nop" ::: "memory");
+        case 4:
+            asm volatile("nop" ::: "memory");
+        case 3:
+            asm volatile("nop" ::: "memory");
+        case 2:
+            asm volatile("nop" ::: "memory");
+        case 1:
+            asm volatile("nop" ::: "memory");
+        case 0:
+            break;
+    }
+}
+#endif
+
 #if defined(__AVR__)
 #    include <util/delay.h>
 #    define wait_ms(ms) _delay_ms(ms)
 #    define wait_us(us) _delay_us(us)
+#    define wait_cpuclock(x) __builtin_avr_delay_cycles(x)
 #elif defined PROTOCOL_CHIBIOS
 #    include <ch.h>
 #    define wait_ms(ms)                     \