Keyboard: Improvement of crkbd communication functions (based on helix-keyboard) (#3798)

* improvement of crkbd communication functions (based on  helix-keyboard)

* Removed unnecessary code.

* Changed read restriction from #define to #pragma once.

* Changed from sizeof to defined size.

* moved lib folder to crkbdroot.
removed warning of ws2812.d

31 files changed, 580 insertions, 233 deletions

diff --git a/keyboards/crkbd/config.h b/keyboards/crkbd/config.h
index c910d8f24f..64fee75457 100644
--- a/keyboards/crkbd/config.h
+++ b/keyboards/crkbd/config.h
@@ -16,9 +16,16 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef CONFIG_H
-#define CONFIG_H
+#pragma once
 
 #include "config_common.h"
+#include <serial_config.h>
 
-#endif
+#ifdef USE_Link_Time_Optimization
+  // LTO has issues with macros (action_get_macro) and "functions" (fn_actions),
+  //  so just disable them
+  #define NO_ACTION_MACRO
+  #define NO_ACTION_FUNCTION
+
+  #define DISABLE_LEADER
+#endif // USE_Link_Time_Optimization
diff --git a/keyboards/crkbd/crkbd.h b/keyboards/crkbd/crkbd.h
index 889bcb9ae3..73f2a3f074 100644
--- a/keyboards/crkbd/crkbd.h
+++ b/keyboards/crkbd/crkbd.h
@@ -1,8 +1,5 @@
-#ifndef CRKBD_H
-#define CRKBD_H
+#pragma once
 
 #ifdef KEYBOARD_crkbd_rev1
   #include "rev1.h"
 #endif
-
-#endif
diff --git a/keyboards/crkbd/i2c.c b/keyboards/crkbd/i2c.c
index 084c890c40..4bee5c6398 100644
--- a/keyboards/crkbd/i2c.c
+++ b/keyboards/crkbd/i2c.c
@@ -34,7 +34,7 @@ void i2c_delay(void) {
   // _delay_us(100);
 }
 
-// Setup twi to run at 100kHz
+// Setup twi to run at 100kHz or 400kHz (see ./i2c.h SCL_CLOCK)
 void i2c_master_init(void) {
   // no prescaler
   TWSR = 0;
diff --git a/keyboards/crkbd/i2c.h b/keyboards/crkbd/i2c.h
index c15b6bc506..710662c7ab 100644
--- a/keyboards/crkbd/i2c.h
+++ b/keyboards/crkbd/i2c.h
@@ -1,5 +1,4 @@
-#ifndef I2C_H
-#define I2C_H
+#pragma once
 
 #include <stdint.h>
 
@@ -15,7 +14,7 @@
 
 #define SLAVE_BUFFER_SIZE 0x10
 
-// i2c SCL clock frequency
+// i2c SCL clock frequency 400kHz
 #define SCL_CLOCK  400000L
 
 extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
@@ -45,5 +44,3 @@ extern unsigned char i2c_readNak(void);
 extern unsigned char i2c_read(unsigned char ack);
 
 #define i2c_read(ack)  (ack) ? i2c_readAck() : i2c_readNak();
-
-#endif
diff --git a/keyboards/crkbd/keymaps/default/keymap.c b/keyboards/crkbd/keymaps/default/keymap.c
index 87661d3451..e92fbdebfa 100644
--- a/keyboards/crkbd/keymaps/default/keymap.c
+++ b/keyboards/crkbd/keymaps/default/keymap.c
@@ -5,7 +5,6 @@
   #include "split_util.h"
 #endif
 #ifdef SSD1306OLED
-  #include "LUFA/Drivers/Peripheral/TWI.h"
   #include "ssd1306.h"
 #endif
 
@@ -130,7 +129,6 @@ void matrix_init_user(void) {
     #endif
     //SSD1306 OLED init, make sure to add #define SSD1306OLED in config.h
     #ifdef SSD1306OLED
-        TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 800000));
         iota_gfx_init(!has_usb());   // turns on the display
     #endif
 }
diff --git a/keyboards/crkbd/keymaps/default/rules.mk b/keyboards/crkbd/keymaps/default/rules.mk
index 6570e2f5cb..0edf1181f0 100644
--- a/keyboards/crkbd/keymaps/default/rules.mk
+++ b/keyboards/crkbd/keymaps/default/rules.mk
@@ -21,10 +21,10 @@ SWAP_HANDS_ENABLE = no        # Enable one-hand typing
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
 # If you want to change the display of OLED, you need to change here
-SRC +=  ../lib/rgb_state_reader.c \
-        ../lib/layer_state_reader.c \
-        ../lib/logo_reader.c \
-        ../lib/keylogger.c \
-        # ../lib/mode_icon_reader.c \
-        # ../lib/host_led_state_reader.c \
-        # ../lib/timelogger.c \
+SRC +=  ./lib/rgb_state_reader.c \
+        ./lib/layer_state_reader.c \
+        ./lib/logo_reader.c \
+        ./lib/keylogger.c \
+        # ./lib/mode_icon_reader.c \
+        # ./lib/host_led_state_reader.c \
+        # ./lib/timelogger.c \
diff --git a/keyboards/crkbd/keymaps/like_jis/keymap.c b/keyboards/crkbd/keymaps/like_jis/keymap.c
index 31b5230b10..90e5b7ec17 100644
--- a/keyboards/crkbd/keymaps/like_jis/keymap.c
+++ b/keyboards/crkbd/keymaps/like_jis/keymap.c
@@ -5,7 +5,6 @@
   #include "split_util.h"
 #endif
 #ifdef SSD1306OLED
-  #include "LUFA/Drivers/Peripheral/TWI.h"
   #include "ssd1306.h"
 #endif
 
@@ -124,7 +123,6 @@ void matrix_init_user(void) {
     #endif
     //SSD1306 OLED init, make sure to add #define SSD1306OLED in config.h
     #ifdef SSD1306OLED
-        TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 800000));
         iota_gfx_init(!has_usb());   // turns on the display
     #endif
 }
diff --git a/keyboards/crkbd/keymaps/like_jis/rules.mk b/keyboards/crkbd/keymaps/like_jis/rules.mk
index 6570e2f5cb..0edf1181f0 100644
--- a/keyboards/crkbd/keymaps/like_jis/rules.mk
+++ b/keyboards/crkbd/keymaps/like_jis/rules.mk
@@ -21,10 +21,10 @@ SWAP_HANDS_ENABLE = no        # Enable one-hand typing
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
 # If you want to change the display of OLED, you need to change here
-SRC +=  ../lib/rgb_state_reader.c \
-        ../lib/layer_state_reader.c \
-        ../lib/logo_reader.c \
-        ../lib/keylogger.c \
-        # ../lib/mode_icon_reader.c \
-        # ../lib/host_led_state_reader.c \
-        # ../lib/timelogger.c \
+SRC +=  ./lib/rgb_state_reader.c \
+        ./lib/layer_state_reader.c \
+        ./lib/logo_reader.c \
+        ./lib/keylogger.c \
+        # ./lib/mode_icon_reader.c \
+        # ./lib/host_led_state_reader.c \
+        # ./lib/timelogger.c \
diff --git a/keyboards/crkbd/keymaps/lib/host_led_state_reader.c b/keyboards/crkbd/lib/host_led_state_reader.c
index 41ac55dc2b..41ac55dc2b 100644
--- a/keyboards/crkbd/keymaps/lib/host_led_state_reader.c
+++ b/keyboards/crkbd/lib/host_led_state_reader.c
diff --git a/keyboards/crkbd/keymaps/lib/keylogger.c b/keyboards/crkbd/lib/keylogger.c
index 8f2a8ce3cc..8f2a8ce3cc 100644
--- a/keyboards/crkbd/keymaps/lib/keylogger.c
+++ b/keyboards/crkbd/lib/keylogger.c
diff --git a/keyboards/crkbd/keymaps/lib/layer_state_reader.c b/keyboards/crkbd/lib/layer_state_reader.c
index eddb71337e..eddb71337e 100644
--- a/keyboards/crkbd/keymaps/lib/layer_state_reader.c
+++ b/keyboards/crkbd/lib/layer_state_reader.c
diff --git a/keyboards/crkbd/keymaps/lib/logo_reader.c b/keyboards/crkbd/lib/logo_reader.c
index 1bc1503a60..1bc1503a60 100644
--- a/keyboards/crkbd/keymaps/lib/logo_reader.c
+++ b/keyboards/crkbd/lib/logo_reader.c
diff --git a/keyboards/crkbd/keymaps/lib/mode_icon_reader.c b/keyboards/crkbd/lib/mode_icon_reader.c
index 04c226506a..04c226506a 100644
--- a/keyboards/crkbd/keymaps/lib/mode_icon_reader.c
+++ b/keyboards/crkbd/lib/mode_icon_reader.c
diff --git a/keyboards/crkbd/keymaps/lib/rgb_state_reader.c b/keyboards/crkbd/lib/rgb_state_reader.c
index e0efe2e528..e0efe2e528 100644
--- a/keyboards/crkbd/keymaps/lib/rgb_state_reader.c
+++ b/keyboards/crkbd/lib/rgb_state_reader.c
diff --git a/keyboards/crkbd/keymaps/lib/timelogger.c b/keyboards/crkbd/lib/timelogger.c
index 69828a3a08..69828a3a08 100644
--- a/keyboards/crkbd/keymaps/lib/timelogger.c
+++ b/keyboards/crkbd/lib/timelogger.c
diff --git a/keyboards/crkbd/pro_micro.h b/keyboards/crkbd/pro_micro.h
index f9e7ed75d9..3666333727 100644
--- a/keyboards/crkbd/pro_micro.h
+++ b/keyboards/crkbd/pro_micro.h
@@ -21,9 +21,7 @@
 
   $Id: wiring.h 249 2007-02-03 16:52:51Z mellis $
 */
-
-#ifndef Pins_Arduino_h
-#define Pins_Arduino_h
+#pragma once
 
 #include <avr/pgmspace.h>
 
@@ -358,5 +356,3 @@ const uint8_t PROGMEM analog_pin_to_channel_PGM[] = {
 #define SERIAL_PORT_USBVIRTUAL     Serial
 #define SERIAL_PORT_HARDWARE       Serial1
 #define SERIAL_PORT_HARDWARE_OPEN  Serial1
-
-#endif /* Pins_Arduino_h */
diff --git a/keyboards/crkbd/rev1/config.h b/keyboards/crkbd/rev1/config.h
index 6321136a73..efce13a490 100644
--- a/keyboards/crkbd/rev1/config.h
+++ b/keyboards/crkbd/rev1/config.h
@@ -16,10 +16,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef REV1_CONFIG_H
-#define REV1_CONFIG_H
-
-#include "../config.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xFEED
@@ -82,6 +79,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-
-#endif
diff --git a/keyboards/crkbd/rev1/matrix.c b/keyboards/crkbd/rev1/matrix.c
index 117ff8d37f..718cc57448 100644
--- a/keyboards/crkbd/rev1/matrix.c
+++ b/keyboards/crkbd/rev1/matrix.c
@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <stdint.h>
 #include <stdbool.h>
+#include <string.h>
 #include <avr/io.h>
 #include <avr/wdt.h>
 #include <avr/interrupt.h>
@@ -30,12 +31,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "matrix.h"
 #include "split_util.h"
 #include "pro_micro.h"
-#include "config.h"
 
 #ifdef USE_MATRIX_I2C
 #  include "i2c.h"
 #else // USE_SERIAL
-#  include "serial.h"
+#  include "split_scomm.h"
 #endif
 
 #ifndef DEBOUNCE
@@ -103,6 +103,8 @@ void matrix_init(void)
     init_cols();
 
     TX_RX_LED_INIT;
+    TXLED0;
+    RXLED0;
 
     // initialize matrix state: all keys off
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
@@ -179,17 +181,20 @@ i2c_error: // the cable is disconnceted, or something else went wrong
 
 #else // USE_SERIAL
 
-int serial_transaction(void) {
+int serial_transaction(int master_changed) {
     int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+    int ret=serial_update_buffers(master_changed);
+#else
     int ret=serial_update_buffers();
+#endif
     if (ret ) {
-        if(ret==2)RXLED1;
+        if(ret==2) RXLED1;
         return 1;
     }
-RXLED0;
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        matrix[slaveOffset+i] = serial_slave_buffer[i];
-    }
+    RXLED0;
+    memcpy(&matrix[slaveOffset],
+        (void *)serial_slave_buffer, SERIAL_SLAVE_BUFFER_LENGTH);
     return 0;
 }
 #endif
@@ -200,19 +205,9 @@ uint8_t matrix_scan(void)
         matrix_master_scan();
     }else{
         matrix_slave_scan();
-
-//        if(serial_slave_DATA_CORRUPT()){
-//          TXLED0;
-          int offset = (isLeftHand) ? ROWS_PER_HAND : 0;
-
-          for (int i = 0; i < ROWS_PER_HAND; ++i) {
-              matrix[offset+i] = serial_master_buffer[i];
-          }
-
-//        }else{
-//          TXLED1;
-//        }
-
+        int offset = (isLeftHand) ? ROWS_PER_HAND : 0;
+        memcpy(&matrix[offset],
+               (void *)serial_master_buffer, SERIAL_MASTER_BUFFER_LENGTH);
         matrix_scan_quantum();
     }
     return 1;
@@ -222,6 +217,7 @@ uint8_t matrix_scan(void)
 uint8_t matrix_master_scan(void) {
 
     int ret = _matrix_scan();
+    int mchanged = 1;
 
     int offset = (isLeftHand) ? 0 : ROWS_PER_HAND;
 
@@ -231,15 +227,18 @@ uint8_t matrix_master_scan(void) {
 //        i2c_slave_buffer[i] = matrix[offset+i];
 //    }
 #else // USE_SERIAL
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        serial_master_buffer[i] = matrix[offset+i];
-    }
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    mchanged = memcmp((void *)serial_master_buffer,
+		      &matrix[offset], SERIAL_MASTER_BUFFER_LENGTH);
+  #endif
+    memcpy((void *)serial_master_buffer,
+	   &matrix[offset], SERIAL_MASTER_BUFFER_LENGTH);
 #endif
 
 #ifdef USE_MATRIX_I2C
     if( i2c_transaction() ) {
 #else // USE_SERIAL
-    if( serial_transaction() ) {
+    if( serial_transaction(mchanged) ) {
 #endif
         // turn on the indicator led when halves are disconnected
         TXLED1;
@@ -273,9 +272,19 @@ void matrix_slave_scan(void) {
         i2c_slave_buffer[i] = matrix[offset+i];
     }
 #else // USE_SERIAL
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    int change = 0;
+  #endif
     for (int i = 0; i < ROWS_PER_HAND; ++i) {
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+        if( serial_slave_buffer[i] != matrix[offset+i] )
+	    change = 1;
+  #endif
         serial_slave_buffer[i] = matrix[offset+i];
     }
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    slave_buffer_change_count += change;
+  #endif
 #endif
 }
 
diff --git a/keyboards/crkbd/rev1/rev1.h b/keyboards/crkbd/rev1/rev1.h
index d02c51f30e..cdd61d2bf9 100644
--- a/keyboards/crkbd/rev1/rev1.h
+++ b/keyboards/crkbd/rev1/rev1.h
@@ -1,5 +1,4 @@
-#ifndef REV1_H
-#define REV1_CONFIG_H
+#pragma once
 
 #include "../crkbd.h"
 
@@ -49,5 +48,3 @@
     KC_##L20, KC_##L21, KC_##L22, KC_##L23, KC_##L24, KC_##L25,                     KC_##R20, KC_##R21, KC_##R22, KC_##R23, KC_##R24, KC_##R25, \
                                             KC_##L30, KC_##L31, KC_##L32, KC_##R30, KC_##R31, KC_##R32 \
   )
-
-#endif
diff --git a/keyboards/crkbd/rev1/rules.mk b/keyboards/crkbd/rev1/rules.mk
index 7af7ffdb8a..6028b5a5b9 100644
--- a/keyboards/crkbd/rev1/rules.mk
+++ b/keyboards/crkbd/rev1/rules.mk
@@ -1,2 +1,3 @@
-SRC += rev1/matrix.c \
-	   ws2812.c
+SRC += rev1/matrix.c
+SRC += rev1/split_util.c
+SRC += rev1/split_scomm.c
diff --git a/keyboards/crkbd/rev1/serial_config.h b/keyboards/crkbd/rev1/serial_config.h
new file mode 100644
index 0000000000..671ed821d2
--- /dev/null
+++ b/keyboards/crkbd/rev1/serial_config.h
@@ -0,0 +1,10 @@
+#pragma once
+
+/* Soft Serial defines */
+#define SERIAL_PIN_DDR DDRD
+#define SERIAL_PIN_PORT PORTD
+#define SERIAL_PIN_INPUT PIND
+#define SERIAL_PIN_MASK _BV(PD2)
+#define SERIAL_PIN_INTERRUPT INT2_vect
+
+#define SERIAL_USE_MULTI_TRANSACTION
diff --git a/keyboards/crkbd/rev1/serial_config_simpleapi.h b/keyboards/crkbd/rev1/serial_config_simpleapi.h
new file mode 100644
index 0000000000..0e1dd9e4ac
--- /dev/null
+++ b/keyboards/crkbd/rev1/serial_config_simpleapi.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#undef SERIAL_USE_MULTI_TRANSACTION
+#define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
+#define SERIAL_MASTER_BUFFER_LENGTH MATRIX_ROWS/2
diff --git a/keyboards/crkbd/rev1/split_scomm.c b/keyboards/crkbd/rev1/split_scomm.c
new file mode 100644
index 0000000000..9719eb22ea
--- /dev/null
+++ b/keyboards/crkbd/rev1/split_scomm.c
@@ -0,0 +1,73 @@
+#ifdef USE_SERIAL
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+/* --- USE flexible API (using multi-type transaction function) --- */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <split_scomm.h>
+#include "serial.h"
+#ifdef SERIAL_DEBUG_MODE
+#include <avr/io.h>
+#endif
+
+uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
+uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
+uint8_t volatile status_com = 0;
+uint8_t volatile status1 = 0;
+uint8_t slave_buffer_change_count = 0;
+uint8_t s_change_old = 0xff;
+
+SSTD_t transactions[] = {
+#define GET_SLAVE_STATUS 0
+    /* master buffer not changed, only recive slave_buffer_change_count */
+    { (uint8_t *)&status_com,
+      0, NULL,
+      sizeof(slave_buffer_change_count), &slave_buffer_change_count,
+    },
+#define PUT_MASTER_GET_SLAVE_STATUS 1
+    /* master buffer changed need send, and recive slave_buffer_change_count  */
+    { (uint8_t *)&status_com,
+      sizeof(serial_master_buffer), (uint8_t *)serial_master_buffer,
+      sizeof(slave_buffer_change_count), &slave_buffer_change_count,
+    },
+#define GET_SLAVE_BUFFER 2
+    /* recive serial_slave_buffer */
+    { (uint8_t *)&status1,
+      0, NULL,
+      sizeof(serial_slave_buffer), (uint8_t *)serial_slave_buffer
+    }
+};
+
+void serial_master_init(void)
+{
+    soft_serial_initiator_init(transactions);
+}
+
+void serial_slave_init(void)
+{
+    soft_serial_target_init(transactions);
+}
+
+// 0 => no error
+// 1 => slave did not respond
+// 2 => checksum error
+int serial_update_buffers(int master_update)
+{
+    int status;
+    static int need_retry = 0;
+    if( s_change_old != slave_buffer_change_count ) {
+	status = soft_serial_transaction(GET_SLAVE_BUFFER);
+	if( status == TRANSACTION_END )
+	    s_change_old = slave_buffer_change_count;
+    }
+    if( !master_update && !need_retry)
+	status = soft_serial_transaction(GET_SLAVE_STATUS);
+    else
+	status = soft_serial_transaction(PUT_MASTER_GET_SLAVE_STATUS);
+    need_retry = ( status == TRANSACTION_END ) ? 0 : 1;
+    return status;
+}
+
+#endif // SERIAL_USE_MULTI_TRANSACTION
+#endif /* USE_SERIAL */
diff --git a/keyboards/crkbd/rev1/split_scomm.h b/keyboards/crkbd/rev1/split_scomm.h
new file mode 100644
index 0000000000..16887eb74f
--- /dev/null
+++ b/keyboards/crkbd/rev1/split_scomm.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+/* --- USE Simple API (OLD API, compatible with let's split serial.c) --- */
+#include "serial.h"
+
+#else
+/* --- USE flexible API (using multi-type transaction function) --- */
+// Buffers for master - slave communication
+#define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
+#define SERIAL_MASTER_BUFFER_LENGTH MATRIX_ROWS/2
+
+extern volatile uint8_t serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH];
+extern volatile uint8_t serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH];
+extern uint8_t slave_buffer_change_count;
+
+void serial_master_init(void);
+void serial_slave_init(void);
+int serial_update_buffers(int master_changed);
+
+#endif
diff --git a/keyboards/crkbd/split_util.c b/keyboards/crkbd/rev1/split_util.c
index 8bc064174e..e1ff8b4379 100644
--- a/keyboards/crkbd/split_util.c
+++ b/keyboards/crkbd/rev1/split_util.c
@@ -7,12 +7,11 @@
 #include "split_util.h"
 #include "matrix.h"
 #include "keyboard.h"
-#include "config.h"
 
 #ifdef USE_MATRIX_I2C
 #  include "i2c.h"
 #else
-#  include "serial.h"
+#  include "split_scomm.h"
 #endif
 
 volatile bool isLeftHand = true;
diff --git a/keyboards/crkbd/split_util.h b/keyboards/crkbd/rev1/split_util.h
index 687ca19bd3..f593047560 100644
--- a/keyboards/crkbd/split_util.h
+++ b/keyboards/crkbd/rev1/split_util.h
@@ -1,5 +1,4 @@
-#ifndef SPLIT_KEYBOARD_UTIL_H
-#define SPLIT_KEYBOARD_UTIL_H
+#pragma once
 
 #include <stdbool.h>
 #include "eeconfig.h"
@@ -15,5 +14,3 @@ void split_keyboard_setup(void);
 bool has_usb(void);
 
 void matrix_master_OLED_init (void);
-
-#endif
diff --git a/keyboards/crkbd/rules.mk b/keyboards/crkbd/rules.mk
index d88daebf3a..6396b115de 100644
--- a/keyboards/crkbd/rules.mk
+++ b/keyboards/crkbd/rules.mk
@@ -1,7 +1,9 @@
-SRC += i2c.c \
-	   serial.c \
-	   split_util.c \
-	   ssd1306.c
+SRC += i2c.c
+SRC += serial.c
+SRC += ssd1306.c
+
+# if firmware size over limit, try this option
+# CFLAGS += -flto
 
 # MCU name
 #MCU = at90usb1287
diff --git a/keyboards/crkbd/serial.c b/keyboards/crkbd/serial.c
index e918ab6ee6..11ceff0b37 100644
--- a/keyboards/crkbd/serial.c
+++ b/keyboards/crkbd/serial.c
@@ -9,36 +9,128 @@
 #include <avr/io.h>
 #include <avr/interrupt.h>
 #include <util/delay.h>
+#include <stddef.h>
 #include <stdbool.h>
 #include "serial.h"
+//#include <pro_micro.h>
 
 #ifdef USE_SERIAL
 
-// Serial pulse period in microseconds. Its probably a bad idea to lower this
-// value.
-#define SERIAL_DELAY 24
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+/* --- USE Simple API (OLD API, compatible with let's split serial.c) */
+  #if SERIAL_SLAVE_BUFFER_LENGTH > 0
+  uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
+  #endif
+  #if SERIAL_MASTER_BUFFER_LENGTH > 0
+  uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
+  #endif
+  uint8_t volatile status0 = 0;
+
+SSTD_t transactions[] = {
+    { (uint8_t *)&status0,
+  #if SERIAL_MASTER_BUFFER_LENGTH > 0
+      sizeof(serial_master_buffer), (uint8_t *)serial_master_buffer,
+  #else
+      0, (uint8_t *)NULL,
+  #endif
+  #if SERIAL_SLAVE_BUFFER_LENGTH > 0
+      sizeof(serial_slave_buffer), (uint8_t *)serial_slave_buffer
+  #else
+      0, (uint8_t *)NULL,
+  #endif
+  }
+};
+
+void serial_master_init(void)
+{ soft_serial_initiator_init(transactions); }
 
-uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
-uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
+void serial_slave_init(void)
+{ soft_serial_target_init(transactions); }
 
-#define SLAVE_DATA_CORRUPT (1<<0)
-volatile uint8_t status = 0;
+// 0 => no error
+// 1 => slave did not respond
+// 2 => checksum error
+int serial_update_buffers()
+{ return soft_serial_transaction(); }
+
+#endif // Simple API (OLD API, compatible with let's split serial.c)
+
+#define ALWAYS_INLINE __attribute__((always_inline))
+#define NO_INLINE __attribute__((noinline))
+#define _delay_sub_us(x)    __builtin_avr_delay_cycles(x)
+
+// Serial pulse period in microseconds.
+#define TID_SEND_ADJUST 14
+
+#define SELECT_SERIAL_SPEED 1
+#if SELECT_SERIAL_SPEED == 0
+  // Very High speed
+  #define SERIAL_DELAY 4             // micro sec
+  #define READ_WRITE_START_ADJUST 33 // cycles
+  #define READ_WRITE_WIDTH_ADJUST 3 // cycles
+#elif SELECT_SERIAL_SPEED == 1
+  // High speed
+  #define SERIAL_DELAY 6             // micro sec
+  #define READ_WRITE_START_ADJUST 30 // cycles
+  #define READ_WRITE_WIDTH_ADJUST 3 // cycles
+#elif SELECT_SERIAL_SPEED == 2
+  // Middle speed
+  #define SERIAL_DELAY 12            // micro sec
+  #define READ_WRITE_START_ADJUST 30 // cycles
+  #define READ_WRITE_WIDTH_ADJUST 3 // cycles
+#elif SELECT_SERIAL_SPEED == 3
+  // Low speed
+  #define SERIAL_DELAY 24            // micro sec
+  #define READ_WRITE_START_ADJUST 30 // cycles
+  #define READ_WRITE_WIDTH_ADJUST 3 // cycles
+#elif SELECT_SERIAL_SPEED == 4
+  // Very Low speed
+  #define SERIAL_DELAY 50            // micro sec
+  #define READ_WRITE_START_ADJUST 30 // cycles
+  #define READ_WRITE_WIDTH_ADJUST 3 // cycles
+#else
+#error Illegal Serial Speed
+#endif
+
+
+#define SERIAL_DELAY_HALF1 (SERIAL_DELAY/2)
+#define SERIAL_DELAY_HALF2 (SERIAL_DELAY - SERIAL_DELAY/2)
+
+#define SLAVE_INT_WIDTH_US 1
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+  #define SLAVE_INT_RESPONSE_TIME SERIAL_DELAY
+#else
+  #define SLAVE_INT_ACK_WIDTH_UNIT 2
+  #define SLAVE_INT_ACK_WIDTH 4
+#endif
+
+static SSTD_t *Transaction_table = NULL;
 
 inline static
 void serial_delay(void) {
   _delay_us(SERIAL_DELAY);
 }
-void serial_delay_short(void) {
-  _delay_us(SERIAL_DELAY-1);
+
+inline static
+void serial_delay_half1(void) {
+  _delay_us(SERIAL_DELAY_HALF1);
+}
+
+inline static
+void serial_delay_half2(void) {
+  _delay_us(SERIAL_DELAY_HALF2);
 }
+
+inline static void serial_output(void) ALWAYS_INLINE;
 inline static
 void serial_output(void) {
   SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
 }
 
 // make the serial pin an input with pull-up resistor
+inline static void serial_input_with_pullup(void) ALWAYS_INLINE;
 inline static
-void serial_input(void) {
+void serial_input_with_pullup(void) {
   SERIAL_PIN_DDR  &= ~SERIAL_PIN_MASK;
   SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
 }
@@ -48,191 +140,305 @@ uint8_t serial_read_pin(void) {
   return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK);
 }
 
+inline static void serial_low(void) ALWAYS_INLINE;
 inline static
 void serial_low(void) {
   SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;
 }
 
+inline static void serial_high(void) ALWAYS_INLINE;
 inline static
 void serial_high(void) {
   SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
 }
 
-void serial_master_init(void) {
-  serial_output();
-  serial_high();
+void soft_serial_initiator_init(SSTD_t *sstd_table)
+{
+    Transaction_table = sstd_table;
+    serial_output();
+    serial_high();
 }
 
-void serial_slave_init(void) {
-  serial_input();
-
-#ifndef USE_SERIAL_PD2
-  // Enable INT0
-  EIMSK |= _BV(INT0);
-  // Trigger on falling edge of INT0
-  EICRA &= ~(_BV(ISC00) | _BV(ISC01));
+void soft_serial_target_init(SSTD_t *sstd_table)
+{
+    Transaction_table = sstd_table;
+    serial_input_with_pullup();
+
+#if SERIAL_PIN_MASK == _BV(PD0)
+    // Enable INT0
+    EIMSK |= _BV(INT0);
+    // Trigger on falling edge of INT0
+    EICRA &= ~(_BV(ISC00) | _BV(ISC01));
+#elif SERIAL_PIN_MASK == _BV(PD2)
+    // Enable INT2
+    EIMSK |= _BV(INT2);
+    // Trigger on falling edge of INT2
+    EICRA &= ~(_BV(ISC20) | _BV(ISC21));
 #else
-  // Enable INT2
-  EIMSK |= _BV(INT2);
-  // Trigger on falling edge of INT2
-  EICRA &= ~(_BV(ISC20) | _BV(ISC21));
+ #error unknown SERIAL_PIN_MASK value
 #endif
 }