Keyboard: [Fortitude60] LED fix and Serial improvement (#3982)

* arrangement Underglow

* modified serial function references from helix

* Remove defines (ws2812_*REG)

9 files changed, 420 insertions, 150 deletions

diff --git a/keyboards/fortitude60/config.h b/keyboards/fortitude60/config.h
index 863722d7d0..27a44ab928 100644
--- a/keyboards/fortitude60/config.h
+++ b/keyboards/fortitude60/config.h
@@ -19,5 +19,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define CONFIG_H
 
 #include "config_common.h"
+#include <serial_config.h>
 
 #endif  // CONFIG_H
diff --git a/keyboards/fortitude60/keymaps/default/config.h b/keyboards/fortitude60/keymaps/default/config.h
index b356791fc8..1748373481 100644
--- a/keyboards/fortitude60/keymaps/default/config.h
+++ b/keyboards/fortitude60/keymaps/default/config.h
@@ -28,7 +28,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // #define MASTER_RIGHT
 #define EE_HANDS
 
-#define USE_SERIAL_PD2
 /* #undef RGBLED_NUM */
 /* #define RGBLIGHT_ANIMATIONS */
 /* #define RGBLED_NUM 12 */
diff --git a/keyboards/fortitude60/keymaps/default/keymap.c b/keyboards/fortitude60/keymaps/default/keymap.c
index 18d2527e45..9d724a8ec6 100644
--- a/keyboards/fortitude60/keymaps/default/keymap.c
+++ b/keyboards/fortitude60/keymaps/default/keymap.c
@@ -119,9 +119,9 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  * ,-----------------------------------------.             ,-----------------------------------------.
  * |   `  |   1  |   2  |   3  |   4  |   5  |             |   6  |   7  |   8  |   9  |   0  | Del  |
  * |------+------+------+------+------+------.             ,------+------+------+------+------+------|
- * |   `  |   1  |   2  |   3  |   4  |   5  |             |   6  |   7  |   8  |   9  |   0  | Bksp |
+ * |   `  |   1  |   ↑  |   3  |   4  |   5  |             |   6  |   7  |   8  |   9  |   0  | Bksp |
  * |------+------+------+------+------+------.             ,------+------+------+------+------+------|
- * | Del  |  F1  |  F2  |  F3  |  F4  |  F5  |             |  F6  |   -  |   =  |   [  |   ]  |  |   |
+ * | Del  |   ←  |   ↓  |   →  |  F4  |  F5  |             |  F6  |   -  |   =  |   [  |   ]  |  |   |
  * |------+------+------+------+------+------+-------------+------+------+------+------+------+------|
  * |      |  F7  |  F8  |  F9  |  F10 |  F11 |      |      |  F12 |ISO # |ISO / |      |      |      |
  * `-------------+------+------+------+------+------+------+------+------+------+------+-------------'
diff --git a/keyboards/fortitude60/keymaps/default/rules.mk b/keyboards/fortitude60/keymaps/default/rules.mk
index e0ed6f0c2d..1964bd0a7c 100644
--- a/keyboards/fortitude60/keymaps/default/rules.mk
+++ b/keyboards/fortitude60/keymaps/default/rules.mk
@@ -1 +1,2 @@
 RGBLIGHT_ENABLE = no
+BACKLIGHT_ENABLE = no
\ No newline at end of file
diff --git a/keyboards/fortitude60/rev1/config.h b/keyboards/fortitude60/rev1/config.h
index 4ba195ff8e..8c6f21afe6 100644
--- a/keyboards/fortitude60/rev1/config.h
+++ b/keyboards/fortitude60/rev1/config.h
@@ -64,12 +64,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 )
 
 /* ws2812 RGB LED */
-/* #define RGB_DI_PIN D3 */
-/* #define RGBLIGHT_TIMER */
-/* #define RGBLED_NUM 16    // Number of LEDs */
-/* #define ws2812_PORTREG  PORTD */
-/* #define ws2812_DDRREG   DDRD */
-
+#ifdef RGBLIGHT_ENABLE
+  #define RGB_DI_PIN B5
+  #define RGBLIGHT_TIMER
+  #define RGBLED_NUM 18    // Number of LEDs */
+#endif
 /*
  * Feature disable options
  *  These options are also useful to firmware size reduction.
diff --git a/keyboards/fortitude60/rev1/rules.mk b/keyboards/fortitude60/rev1/rules.mk
index bd518d8f27..e69de29bb2 100644
--- a/keyboards/fortitude60/rev1/rules.mk
+++ b/keyboards/fortitude60/rev1/rules.mk
@@ -1 +0,0 @@
-BACKLIGHT_ENABLE = yes
diff --git a/keyboards/fortitude60/serial.c b/keyboards/fortitude60/serial.c
index 46dfad021d..cea1a5f6ca 100644
--- a/keyboards/fortitude60/serial.c
+++ b/keyboards/fortitude60/serial.c
@@ -9,20 +9,102 @@
 #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
+
+#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); }
 
-#ifndef USE_I2C
+void serial_slave_init(void)
+{ soft_serial_target_init(transactions); }
 
-// Serial pulse period in microseconds. Its probably a bad idea to lower this
-// value.
-#define SERIAL_DELAY 24
+// 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
 
-uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
-uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
 
-#define SLAVE_DATA_CORRUPT (1<<0)
-volatile uint8_t status = 0;
+#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) {
@@ -30,13 +112,25 @@ void serial_delay(void) {
 }
 
 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;
 }
@@ -46,190 +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
 }
 
-// Used by the master to synchronize timing with the slave.
+// Used by the sender to synchronize timing with the reciver.
+static void sync_recv(void) NO_INLINE;
 static
 void sync_recv(void) {
-  serial_input();
-  // This shouldn't hang if the slave disconnects because the
-  // serial line will float to high if the slave does disconnect.
+  for (uint8_t i = 0; i < SERIAL_DELAY*5 && serial_read_pin(); i++ ) {
+  }
+  // This shouldn't hang if the target disconnects because the
+  // serial line will float to high if the target does disconnect.
   while (!serial_read_pin());
-  serial_delay();
 }
 
-// Used by the slave to send a synchronization signal to the master.
+// Used by the reciver to send a synchronization signal to the sender.
+static void sync_send(void)NO_INLINE;
 static
 void sync_send(void) {
-  serial_output();
-
   serial_low();
   serial_delay();
-
   serial_high();
 }
 
 // Reads a byte from the serial line
-static
-uint8_t serial_read_byte(void) {
-  uint8_t byte = 0;
-  serial_input();
-  for ( uint8_t i = 0; i < 8; ++i) {
-    byte = (byte << 1) | serial_read_pin();
-    serial_delay();
-    _delay_us(1);
+static uint8_t serial_read_chunk(uint8_t *pterrcount, uint8_t bit) NO_INLINE;
+static uint8_t serial_read_chunk(uint8_t *pterrcount, uint8_t bit) {
+    uint8_t byte, i, p, pb;
+
+  _delay_sub_us(READ_WRITE_START_ADJUST);
+  for( i = 0, byte = 0, p = 0; i < bit; i++ ) {
+      serial_delay_half1();   // read the middle of pulses
+      if( serial_read_pin() ) {
+	  byte = (byte << 1) | 1; p ^= 1;
+      } else {
+	  byte = (byte << 1) | 0; p ^= 0;
+      }
+      _delay_sub_us(READ_WRITE_WIDTH_ADJUST);
+      serial_delay_half2();
   }
+  /* recive parity bit */
+  serial_delay_half1();   // read the middle of pulses
+  pb = serial_read_pin();
+  _delay_sub_us(READ_WRITE_WIDTH_ADJUST);
+  serial_delay_half2();
+
+  *pterrcount += (p != pb)? 1 : 0;
 
   return byte;
 }
 
 // Sends a byte with MSB ordering
-static
-void serial_write_byte(uint8_t data) {
-  uint8_t b = 8;
-  serial_output();
-  while( b-- ) {
-    if(data & (1 << b)) {
-      serial_high();
-    } else {
-      serial_low();
+void serial_write_chunk(uint8_t data, uint8_t bit) NO_INLINE;
+void serial_write_chunk(uint8_t data, uint8_t bit) {
+    uint8_t b, p;
+    for( p = 0, b = 1<<(bit-1); b ; b >>= 1) {
+	if(data & b) {
+	    serial_high(); p ^= 1;
+	} else {
+	    serial_low();  p ^= 0;
+	}
+	serial_delay();
     }
+    /* send parity bit */
+    if(p & 1) { serial_high(); }
+    else      { serial_low(); }
     serial_delay();
-  }
-}
 
-// interrupt handle to be used by the slave device
-ISR(SERIAL_PIN_INTERRUPT) {
-  sync_send();
+    serial_low(); // sync_send() / senc_recv() need raise edge
+}
 
-  uint8_t checksum = 0;
-  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
-    serial_write_byte(serial_slave_buffer[i]);
+static void serial_send_packet(uint8_t *buffer, uint8_t size) NO_INLINE;
+static
+void serial_send_packet(uint8_t *buffer, uint8_t size) {
+  for (uint8_t i = 0; i < size; ++i) {
+    uint8_t data;
+    data = buffer[i];
     sync_send();
-    checksum += serial_slave_buffer[i];
+    serial_write_chunk(data,8);
   }
-  serial_write_byte(checksum);
-  sync_send();
+}
 
-  // wait for the sync to finish sending
-  serial_delay();
+static uint8_t serial_recive_packet(uint8_t *buffer, uint8_t size) NO_INLINE;
+static
+uint8_t serial_recive_packet(uint8_t *buffer, uint8_t size) {
+  uint8_t pecount = 0;
+  for (uint8_t i = 0; i < size; ++i) {
+    uint8_t data;
+    sync_recv();
+    data = serial_read_chunk(&pecount, 8);
+    buffer[i] = data;
+  }
+  return pecount == 0;
+}
 
-  // read the middle of pulses
-  _delay_us(SERIAL_DELAY/2);
+inline static
+void change_sender2reciver(void) {
+    sync_send();          //0
+    serial_delay_half1(); //1
+    serial_low();         //2
+    serial_input_with_pullup(); //2
+    serial_delay_half1(); //3
+}
 
-  uint8_t checksum_computed = 0;
-  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
-    serial_master_buffer[i] = serial_read_byte();
-    sync_send();
-    checksum_computed += serial_master_buffer[i];
-  }
-  uint8_t checksum_received = serial_read_byte();
-  sync_send();
+inline static
+void change_reciver2sender(void) {
+    sync_recv();     //0
+    serial_delay();  //1
+    serial_low();    //3
+    serial_output(); //3
+    serial_delay_half1(); //4
+}
 
-  serial_input(); // end transaction
+// interrupt handle to be used by the target device
+ISR(SERIAL_PIN_INTERRUPT) {
 
-  if ( checksum_computed != checksum_received ) {
-    status |= SLAVE_DATA_CORRUPT;
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+  serial_low();
+  serial_output();
+  SSTD_t *trans = Transaction_table;
+#else
+  // recive transaction table index
+  uint8_t tid;
+  uint8_t pecount = 0;
+  sync_recv();
+  tid = serial_read_chunk(&pecount,4);
+  if(pecount> 0)
+      return;
+  serial_delay_half1();
+
+  serial_high(); // response step1 low->high
+  serial_output();
+  _delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT*SLAVE_INT_ACK_WIDTH);
+  SSTD_t *trans = &Transaction_table[tid];
+  serial_low(); // response step2 ack high->low
+#endif
+
+  // target send phase
+  if( trans->target2initiator_buffer_size > 0 )
+      serial_send_packet((uint8_t *)trans->target2initiator_buffer,
+			 trans->target2initiator_buffer_size);
+  // target switch to input
+  change_sender2reciver();
+
+  // target recive phase
+  if( trans->initiator2target_buffer_size > 0 ) {
+      if (serial_recive_packet((uint8_t *)trans->initiator2target_buffer,
+			       trans->initiator2target_buffer_size) ) {
+	  *trans->status = TRANSACTION_ACCEPTED;
+      } else {
+	  *trans->status = TRANSACTION_DATA_ERROR;
+      }
   } else {
-    status &= ~SLAVE_DATA_CORRUPT;
+      *trans->status = TRANSACTION_ACCEPTED;
   }
-}
 
-inline
-bool serial_slave_DATA_CORRUPT(void) {
-  return status & SLAVE_DATA_CORRUPT;
+  sync_recv(); //weit initiator output to high
 }
 
-// Copies the serial_slave_buffer to the master and sends the
-// serial_master_buffer to the slave.
+/////////
+//  start transaction by initiator
+//
+// int  soft_serial_transaction(int sstd_index)
 //
 // Returns:
-// 0 => no error
-// 1 => slave did not respond
-int serial_update_buffers(void) {
-  // this code is very time dependent, so we need to disable interrupts
+//    TRANSACTION_END
+//    TRANSACTION_NO_RESPONSE
+//    TRANSACTION_DATA_ERROR
+// this code is very time dependent, so we need to disable interrupts
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+int  soft_serial_transaction(void) {
+  SSTD_t *trans = Transaction_table;
+#else
+int  soft_serial_transaction(int sstd_index) {
+  SSTD_t *trans = &Transaction_table[sstd_index];
+#endif
   cli();
 
-  // signal to the slave that we want to start a transaction
+  // signal to the target that we want to start a transaction
   serial_output();
   serial_low();
-  _delay_us(1);
+  _delay_us(SLAVE_INT_WIDTH_US);
 
-  // wait for the slaves response
-  serial_input();
-  serial_high();
-  _delay_us(SERIAL_DELAY);
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+  // wait for the target response
+  serial_input_with_pullup();
+  _delay_us(SLAVE_INT_RESPONSE_TIME);
 
-  // check if the slave is present
+  // check if the target is present
   if (serial_read_pin()) {
-    // slave failed to pull the line low, assume not present
+    // target failed to pull the line low, assume not present
+    serial_output();
+    serial_high();
+    *trans->status = TRANSACTION_NO_RESPONSE;
     sei();
-    return 1;
+    return TRANSACTION_NO_RESPONSE;
   }
 
-  // if the slave is present syncronize with it
-  sync_recv();
-
-  uint8_t checksum_computed = 0;
-  // receive data from the slave
-  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
-    serial_slave_buffer[i] = serial_read_byte();
-    sync_recv();
-    checksum_computed += serial_slave_buffer[i];
+#else
+  // send transaction table index
+  sync_send();
+  _delay_sub_us(TID_SEND_ADJUST);
+  serial_write_chunk(sstd_index, 4);
+  serial_delay_half1();
+
+  // wait for the target response (step1 low->high)
+  serial_input_with_pullup();
+  while( !serial_read_pin() ) {
+      _delay_sub_us(2);
   }
-  uint8_t checksum_received = serial_read_byte();
-  sync_recv();
 
-  if (checksum_computed != checksum_received) {
-    sei();
-    return 2;
+  // check if the target is present (step2 high->low)
+  for( int i = 0; serial_read_pin(); i++ ) {
+      if (i > SLAVE_INT_ACK_WIDTH + 1) {
+	  // slave failed to pull the line low, assume not present
+	  serial_output();
+	  serial_high();
+	  *trans->status = TRANSACTION_NO_RESPONSE;
+	  sei();
+	  return TRANSACTION_NO_RESPONSE;
+      }
+      _delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT);
   }
+#endif
 
-  uint8_t checksum = 0;
-  // send data to the slave
-  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
-    serial_write_byte(serial_master_buffer[i]);
-    sync_recv();
-    checksum += serial_master_buffer[i];
+  // initiator recive phase
+  // if the target is present syncronize with it
+  if( trans->target2initiator_buffer_size > 0 ) {
+      if (!serial_recive_packet((uint8_t *)trans->target2initiator_buffer,
+				trans->target2initiator_buffer_size) ) {
+	  serial_output();
+	  serial_high();
+	  *trans->status = TRANSACTION_DATA_ERROR;
+	  sei();
+	  return TRANSACTION_DATA_ERROR;
+      }
+   }
+
+  // initiator switch to output
+  change_reciver2sender();
+
+  // initiator send phase
+  if( trans->initiator2target_buffer_size > 0 ) {
+      serial_send_packet((uint8_t *)trans->initiator2target_buffer,
+			 trans->initiator2target_buffer_size);
   }
-  serial_write_byte(checksum);
-  sync_recv();
 
   // always, release the line when not in use
-  serial_output();
-  serial_high();
+  sync_send();
 
+  *trans->status = TRANSACTION_END;
   sei();
-  return 0;
+  return TRANSACTION_END;
 }
 
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+int soft_serial_get_and_clean_status(int sstd_index) {
+    SSTD_t *trans = &Transaction_table[sstd_index];
+    cli();
+    int retval = *trans->status;
+    *trans->status = 0;;
+    sei();
+    return retval;
+}
 #endif
+
+#endif
\ No newline at end of file
diff --git a/keyboards/fortitude60/serial.h b/keyboards/fortitude60/serial.h
index 361f1881b6..d008980556 100644
--- a/keyboards/fortitude60/serial.h
+++ b/keyboards/fortitude60/serial.h
@@ -1,32 +1,80 @@
-#ifndef MY_SERIAL_H
-#define MY_SERIAL_H
+#ifndef SOFT_SERIAL_H
+#define SOFT_SERIAL_H
 
-#include "config.h"
 #include <stdbool.h>
 
-/* TODO:  some defines for interrupt setup */
-#define SERIAL_PIN_DDR DDRD
-#define SERIAL_PIN_PORT PORTD
-#define SERIAL_PIN_INPUT PIND
+// /////////////////////////////////////////////////////////////////
+// Need Soft Serial defines in serial_config.h
+// /////////////////////////////////////////////////////////////////
+// ex.
+//  #define SERIAL_PIN_DDR DDRD
+//  #define SERIAL_PIN_PORT PORTD
+//  #define SERIAL_PIN_INPUT PIND
+//  #define SERIAL_PIN_MASK _BV(PD?)   ?=0,2
+//  #define SERIAL_PIN_INTERRUPT INT?_vect  ?=0,2
+//
+// //// USE Simple API (OLD API, compatible with let's split serial.c)
+// ex.
+//  #define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
+//  #define SERIAL_MASTER_BUFFER_LENGTH 1
+//
+// //// USE flexible API (using multi-type transaction function)
+//  #define SERIAL_USE_MULTI_TRANSACTION
+//
+// /////////////////////////////////////////////////////////////////
 
-#ifndef USE_SERIAL_PD2
-#define SERIAL_PIN_MASK _BV(PD0)
-#define SERIAL_PIN_INTERRUPT INT0_vect
-#else
-#define SERIAL_PIN_MASK _BV(PD2)
-#define SERIAL_PIN_INTERRUPT INT2_vect
-#endif
-
-#define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
-#define SERIAL_MASTER_BUFFER_LENGTH 1
 
-// Buffers for master - slave communication
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+/* --- USE Simple API (OLD API, compatible with let's split serial.c) */
+#if SERIAL_SLAVE_BUFFER_LENGTH > 0
 extern volatile uint8_t serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH];
+#endif
+#if SERIAL_MASTER_BUFFER_LENGTH > 0
 extern volatile uint8_t serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH];
+#endif
 
 void serial_master_init(void);
 void serial_slave_init(void);
 int serial_update_buffers(void);
-bool serial_slave_data_corrupt(void);
 
+#endif // USE Simple API
+
+// Soft Serial Transaction Descriptor
+typedef struct _SSTD_t  {
+    uint8_t *status;
+    uint8_t initiator2target_buffer_size;
+    uint8_t *initiator2target_buffer;
+    uint8_t target2initiator_buffer_size;
+    uint8_t *target2initiator_buffer;
+} SSTD_t;
+
+// initiator is transaction start side
+void soft_serial_initiator_init(SSTD_t *sstd_table);
+// target is interrupt accept side
+void soft_serial_target_init(SSTD_t *sstd_table);
+
+// initiator resullt
+#define TRANSACTION_END 0
+#define TRANSACTION_NO_RESPONSE 0x1
+#define TRANSACTION_DATA_ERROR  0x2
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+int  soft_serial_transaction(void);
+#else
+int  soft_serial_transaction(int sstd_index);
 #endif
+
+// target status
+// *SSTD_t.status has
+//   initiator:
+//       TRANSACTION_END
+//    or TRANSACTION_NO_RESPONSE
+//    or TRANSACTION_DATA_ERROR
+//   target:
+//       TRANSACTION_DATA_ERROR
+//    or TRANSACTION_ACCEPTED
+#define TRANSACTION_ACCEPTED 0x4
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+int  soft_serial_get_and_clean_status(int sstd_index);
+#endif
+
+#endif /* SOFT_SERIAL_H */
\ No newline at end of file
diff --git a/keyboards/fortitude60/serial_config.h b/keyboards/fortitude60/serial_config.h
new file mode 100644
index 0000000000..96a54afbd8
--- /dev/null
+++ b/keyboards/fortitude60/serial_config.h
@@ -0,0 +1,14 @@
+#ifndef SOFT_SERIAL_CONFIG_H
+#define SOFT_SERIAL_CONFIG_H
+
+/* 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_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
+#define SERIAL_MASTER_BUFFER_LENGTH 1
+
+#endif /* SOFT_SERIAL_CONFIG_H */
\ No newline at end of file