commit a8eccba5db582cd374add9ef53588ff001099e2c
Author: flovenol <flovenol@gmail.com>
Date:   Sat Sep 28 00:15:00 2019 +0200

    initial commit

diff --git a/Keyboard.ino b/Keyboard.ino
new file mode 100644
index 0000000..ee5acf4
--- /dev/null
+++ b/Keyboard.ino
@@ -0,0 +1,97 @@
+void send_data_to_kbd(byte data, kbd_state next_state) {
+  if (!kbd_clock_detected) {
+    pinMode(DATA_KBD, OUTPUT);
+    digitalWrite(DATA_KBD, LOW);
+    kbd_clock_read = digitalRead(CLK_KBD);
+    if (kbd_clock_read == LOW) {
+      kbd_clock_detected = true;
+      kbd_clock_state=LOW;
+    } else {
+      check_kbd_clock_start();
+      return;
+    }
+  }
+  
+  digitalWrite(DATA_KBD, data>>(7 - kbd_clock_count) & 1);
+  kbd_clock_read = digitalRead(CLK_KBD);
+  if (kbd_clock_read  != kbd_clock_state) {
+    kbd_clock_transition_start = 0;
+    kbd_clock_state = kbd_clock_read;
+    if (kbd_clock_state == LOW) {
+      kbd_clock_count++;
+    }
+
+    if (kbd_clock_state == HIGH && kbd_clock_count == 7) {
+      digitalWrite(DATA_KBD, HIGH);
+      kbd_reset();
+      keyboard_state = next_state;
+    }
+  } else {
+    check_clock_transition();    
+  }  
+}
+
+void read_data_from_kbd(kbd_state next_state) {
+  if (!kbd_clock_detected) {
+    pinMode(DATA_KBD, INPUT);
+    kbd_clock_read = digitalRead(CLK_KBD);
+    if (kbd_clock_read == LOW) {
+      kbd_clock_detected = true;
+      kbd_clock_state=LOW;
+    } else {
+      check_kbd_clock_start();
+      return;
+    }
+  }
+   
+  kbd_clock_read = digitalRead(CLK_KBD);
+  if (kbd_clock_read  != kbd_clock_state) {
+    kbd_clock_transition_start = 0;
+    kbd_clock_state = kbd_clock_read;
+    if (kbd_clock_state == HIGH) {
+      if (digitalRead(DATA_KBD) == HIGH) {
+        kbd_data_read |= 1<<(7 - kbd_clock_count);
+      }
+    }
+    if (kbd_clock_state == LOW) {
+      kbd_clock_count++;
+    }
+
+    if (kbd_clock_state == HIGH && kbd_clock_count == 7) {
+        if (keyboard_state == READ_MODEL_NUMBER) {
+          model_number = kbd_data_read;
+        } else if (kbd_data_read != TEST_ACK && kbd_data_read != TEST_NAK) {
+          kbd_last_data_read_index = (kbd_last_data_read_index + 1) % 4;
+          kbd_last_data_read[kbd_last_data_read_index] = kbd_data_read;
+        }
+  
+        /*if (kbd_data_read != NULL_TRANSITION && kbd_data_read != TEST_ACK) {
+          Serial.print("Data read: ");
+          Serial.println(kbd_data_read, BIN);
+        }*/
+          
+        kbd_reset();
+        keyboard_state = next_state;                    
+    }
+  } else {
+    check_clock_transition(); 
+  }
+}
+
+void check_kbd_clock_start() {
+  if (kbd_clock_start == 0) {
+    kbd_clock_start = millis();
+  } else if (millis() - kbd_clock_start >= CLOCK_START_MSEC) {
+    //Serial.println("Failed to receive clock signal, resetting");
+    kbd_hard_reset();
+  }
+}
+
+void check_clock_transition() {
+  if (kbd_clock_transition_start == 0) {
+    kbd_clock_transition_start = micros();
+  } else if (micros() - kbd_clock_transition_start >= CLOCK_TRANSITION_USEC) {
+    //Serial.println("Failed to receive proper clock signal, resetting");
+    kbd_hard_reset();
+  }
+}
diff --git a/KeyboardRemapper.ino b/KeyboardRemapper.ino
new file mode 100644
index 0000000..6856ec6
--- /dev/null
+++ b/KeyboardRemapper.ino
@@ -0,0 +1,120 @@
+#define CLK_MAC 15
+#define DATA_MAC 14
+
+#define CLK_KBD 16
+#define DATA_KBD 10
+
+#define CLOCK_START_MSEC 500
+#define CLOCK_TRANSITION_USEC 300
+#define CLOCK_READ_LOW_USEC 180
+#define CLOCK_READ_HIGH_USEC 200
+#define CLOCK_WRITE_LOW_USEC 180
+#define CLOCK_WRITE_HIGH_USEC 200
+#define MAC_RESP_DELAY_MSEC 240
+#define MAC_DETECT_READY_USEC 300
+
+// command constants
+const byte MODEL_NUMBER_CMD = 0x16;
+const byte TEST_CMD = 0x36;
+const byte INQUIRY_CMD = 0x10;
+const byte INSTANT_CMD = 0x14;
+
+// command response constants
+const byte NULL_TRANSITION = 0x7B;
+const byte TEST_ACK = 0x7D;
+const byte TEST_NAK = 0x77;
+const byte BAD_CMD = 0x00;
+
+enum kbd_state { 
+  REQUIRE_MODEL_NUMBER,
+  READ_MODEL_NUMBER,
+  REQUIRE_TEST,
+  READ_TEST,
+  REQUIRE_INQUIRY,
+  READ_INQUIRY,
+  DELAY_INQUIRY
+};
+
+enum mac_state {
+  DETECT_READY_FOR_CMD,
+  READ_CMD,
+  DETECT_READY_FOR_DATA,
+  WRITE_DATA
+};
+
+// keyboard state variables
+kbd_state keyboard_state = REQUIRE_MODEL_NUMBER;
+boolean kbd_clock_detected;
+boolean kbd_clock_state;
+boolean kbd_clock_read;
+unsigned int kbd_clock_count;
+unsigned long kbd_clock_start;
+unsigned long kbd_clock_transition_start;
+unsigned long kbd_delay_start;
+
+byte kbd_data_read;
+byte kbd_last_data_read[4];
+short kbd_last_data_read_index = -1;
+byte model_number;
+
+// macintosh state variables
+mac_state macintosh_state = DETECT_READY_FOR_CMD;
+boolean mac_ready_detected;
+unsigned long mac_delay_start;
+boolean mac_clock_started;
+boolean mac_clock_state;
+unsigned int mac_clock_count;
+unsigned long mac_clock_delay_start;
+unsigned long mac_cmd_response_delay_start;
+
+byte mac_data_read;
+byte last_mac_cmd;
+byte mac_data_write;
+
+
+void setup() {
+  pinMode(CLK_MAC, OUTPUT);
+  digitalWrite(CLK_MAC, HIGH);
+  pinMode(CLK_KBD, INPUT);
+  kbd_hard_reset();
+  //Serial.begin(19200);
+}
+
+void loop() {
+  switch (keyboard_state) {
+    case REQUIRE_MODEL_NUMBER:
+      send_data_to_kbd(MODEL_NUMBER_CMD, READ_MODEL_NUMBER);
+      break;
+    case READ_MODEL_NUMBER:
+      read_data_from_kbd(REQUIRE_TEST);
+      break;
+    case REQUIRE_TEST:
+      send_data_to_kbd(TEST_CMD, READ_TEST);
+      break;
+    case READ_TEST:
+      read_data_from_kbd(REQUIRE_INQUIRY);
+      break;
+    case REQUIRE_INQUIRY:
+      send_data_to_kbd(INQUIRY_CMD, READ_INQUIRY);
+      break;
+    case READ_INQUIRY:
+      read_data_from_kbd(REQUIRE_INQUIRY);
+      break;
+  }
+
+  switch (macintosh_state) {
+    case DETECT_READY_FOR_CMD:
+      mac_detect_ready_to_send_cmd();
+      break;
+    case READ_CMD:
+      mac_read_data();
+      break;
+    case DETECT_READY_FOR_DATA:
+      mac_detect_ready_to_recv_data();
+      break;
+    case WRITE_DATA:
+      mac_write_data();
+      break;
+  }
+  
+}
diff --git a/Macintosh.ino b/Macintosh.ino
new file mode 100644
index 0000000..a8b8bbc
--- /dev/null
+++ b/Macintosh.ino
@@ -0,0 +1,158 @@
+void mac_detect_ready_to_send_cmd() {
+  if (!mac_ready_detected) {
+    pinMode(DATA_MAC, INPUT);
+    if (digitalRead(DATA_MAC) == LOW) {
+      mac_ready_detected = true;  
+    }
+  } else {
+    if (mac_delay_start == 0) {
+      mac_delay_start = micros(); 
+    }
+
+    if (micros() - mac_delay_start >= MAC_DETECT_READY_USEC) {
+      mac_reset();
+      macintosh_state = READ_CMD;
+    }
+  }
+}
+
+void mac_detect_ready_to_recv_data() {
+  if (mac_delay_start == 0) {
+    mac_delay_start = micros(); 
+    pinMode(DATA_MAC, INPUT);
+  }
+
+  if (micros() - mac_delay_start >= 400) {
+    if (digitalRead(DATA_MAC) == HIGH) {
+      macintosh_state = WRITE_DATA;
+    } else {
+      macintosh_state = DETECT_READY_FOR_CMD;
+    }
+    mac_reset();
+  }
+}
+
+void mac_read_data() {
+  if (!mac_clock_started) {
+    pinMode(DATA_MAC, INPUT);
+    mac_clock_state = LOW;
+    mac_clock_started = true;
+  }
+
+  if (mac_clock_state == LOW) {
+    if (mac_clock_delay_start == 0) {
+      digitalWrite(CLK_MAC, LOW);
+      mac_clock_delay_start = micros();
+    }
+
+    if (micros() - mac_clock_delay_start >= CLOCK_READ_LOW_USEC) {
+      mac_clock_state = HIGH;
+      mac_clock_delay_start = 0;  
+    }
+  }
+
+  if (mac_clock_state == HIGH) {
+    if (mac_clock_delay_start == 0) {
+      digitalWrite(CLK_MAC, HIGH);
+      mac_clock_delay_start = micros();
+      
+      if (digitalRead(DATA_MAC) == HIGH) {
+        mac_data_read |= 1<<(7 - mac_clock_count);  
+      }
+    }
+
+    if (micros() - mac_clock_delay_start >= CLOCK_READ_HIGH_USEC) {
+      if (mac_clock_count < 7) {
+        mac_clock_state = LOW;
+        mac_clock_delay_start = 0;
+        mac_clock_count++;
+      } else {
+        last_mac_cmd = mac_data_read;
+        mac_reset();
+        macintosh_state = DETECT_READY_FOR_DATA;  
+      }
+    }
+  }
+}
+
+void mac_write_data() {
+  if (!mac_clock_started) {
+    if (last_mac_cmd == INQUIRY_CMD && kbd_last_data_read_index == -1) {
+      if (mac_cmd_response_delay_start == 0) {
+        mac_cmd_response_delay_start = millis();
+      }
+
+      if (millis() - mac_cmd_response_delay_start >= MAC_RESP_DELAY_MSEC) {
+        goto WRITE_MAC;
+      } else {
+        return;
+      }
+    } else {
+      WRITE_MAC:
+      
+      mac_data_write = mac_cmd_response_data();
+      if (mac_data_write == BAD_CMD) {
+         mac_reset();
+         macintosh_state = DETECT_READY_FOR_CMD;
+         return;
+      } else {
+        pinMode(DATA_MAC, OUTPUT);
+        mac_clock_state = LOW;
+        mac_clock_started = true;
+      }
+    }
+  }
+  
+  if (mac_clock_state == LOW) {
+    if (mac_clock_delay_start == 0) {
+      digitalWrite(CLK_MAC, LOW);
+      mac_clock_delay_start = micros();
+
+      digitalWrite(DATA_MAC, mac_data_write>>(7 - mac_clock_count) & 1 > 0);
+    }
+
+    if (micros() - mac_clock_delay_start >= CLOCK_WRITE_LOW_USEC) {
+      mac_clock_state = HIGH;
+      mac_clock_delay_start = 0;  
+    }
+  }
+
+  if (mac_clock_state == HIGH) {
+    if (mac_clock_delay_start == 0) {
+      digitalWrite(CLK_MAC, HIGH);
+      mac_clock_delay_start = micros();
+    }
+
+    if (micros() - mac_clock_delay_start >= CLOCK_WRITE_HIGH_USEC) {
+      if (mac_clock_count < 7) {
+        mac_clock_state = LOW;
+        mac_clock_delay_start = 0;
+        mac_clock_count++;
+      } else {
+        digitalWrite(DATA_MAC, HIGH);
+        mac_reset();
+        macintosh_state = DETECT_READY_FOR_CMD;
+      }
+    }
+  }
+}
+
+byte mac_cmd_response_data() {
+  switch (last_mac_cmd) {
+    case MODEL_NUMBER_CMD:
+      return model_number;
+    case TEST_CMD:
+      return TEST_ACK;
+    case INSTANT_CMD:
+    case INQUIRY_CMD:
+      if (kbd_last_data_read_index == -1) {
+        return NULL_TRANSITION;
+      }
+      byte inquiry_data = kbd_last_data_read[0];
+      kbd_last_data_read[0] = kbd_last_data_read[1];
+      kbd_last_data_read[1] = kbd_last_data_read[2];
+      kbd_last_data_read[2] = kbd_last_data_read[3];
+      kbd_last_data_read_index -= 1;
+      return remap(inquiry_data);
+  }
+}
diff --git a/Mapping.ino b/Mapping.ino
new file mode 100644
index 0000000..0b5442e
--- /dev/null
+++ b/Mapping.ino
@@ -0,0 +1,98 @@
+
+byte remap(byte kbd_data) {
+  switch (kbd_data) {
+    
+    // Return
+    case 0xD5:
+      return 0xC9;
+    case 0x55:
+      return 0x49;
+
+    // backslash
+    case 0xC9:
+      return 0xD5;
+    case 0x49:
+      return 0x55;
+
+    // space
+    case 0xE9:
+      return 0xE3;
+    case 0x69:
+      return 0x63;
+
+    // Enter
+    case 0xE3:
+      return 0xE9;
+    case 0x63:
+      return 0x69;
+
+    // z
+    case 0xA1:
+      return 0x8D;
+    case 0x21:
+      return 0x0D;
+
+    // y
+    case 0x8F:
+      return 0xA1;
+    case 0x0F:
+      return 0x21;
+
+    // x
+    case 0x91:
+      return 0x8F;
+    case 0x11:
+      return 0x0F;
+
+    // c
+    case 0x93:
+      return 0x91;
+    case 0x13:
+      return 0x11;
+
+    // v
+    case 0x97:
+      return 0x93;
+    case 0x17:
+      return 0x13;
+
+    // b
+    case 0xDB:
+      return 0x97;
+    case 0x5B:
+      return 0x17;
+    
+    // n
+    case 0xDD:
+      return 0xDB;
+    case 0x5D:
+      return 0x5B;
+
+    // m
+    case 0xD7:
+      return 0xDD;
+    case 0x57:
+      return 0x5D;
+
+    // .
+    case 0xD9:
+      return 0xDF;
+    case 0x59:
+      return 0x5F;
+
+    // /
+    case 0x95:
+      return 0xD9;
+    case 0x15:
+      return 0x59; 
+    
+    // ,
+    case 0xDF:
+      return 0xD7;
+    case 0x5F:
+      return 0x57;   
+     
+    default:
+    return kbd_data;
+  }
+}
diff --git a/Reset.ino b/Reset.ino
new file mode 100644
index 0000000..2acec78
--- /dev/null
+++ b/Reset.ino
@@ -0,0 +1,28 @@
+void kbd_hard_reset() {
+  kbd_reset();
+  model_number = BAD_CMD;
+  kbd_last_data_read_index = -1;
+  keyboard_state = REQUIRE_MODEL_NUMBER;
+}
+
+void kbd_reset() {
+  kbd_clock_count = 0;
+  kbd_clock_detected = false;
+  kbd_clock_state = HIGH;
+  kbd_clock_start = 0;
+  kbd_clock_transition_start = 0;
+  kbd_delay_start = 0;
+  kbd_data_read = 0x00;
+}
+
+void mac_reset() {
+  mac_ready_detected = false;
+  mac_delay_start = 0;
+  mac_clock_state = HIGH;
+  mac_clock_started = false;
+  mac_clock_count = 0;
+  mac_clock_delay_start = 0;
+  mac_cmd_response_delay_start = 0;
+  mac_data_read = 0x00;
+  mac_data_write = 0x00;
+}