arduino_c128_u36_switch.txt

#include <EEPROM.h>
 
// C128 8 in 1 27c020 u36 rom switch
// Based on C64 Kernel Switcher and Restore Key Reset/Selector
// version 1.1 -- 26-March-2019 By Adrian Black
// restore key mod: https://www.breadbox64.com/blog/c64-restore-mod/

// modded by insanity 2-April-2021 to add Basic ROM switch needed for OpenROMS Kernal compatibility
// added additional reset to work around RAM bug during EXROM reset in OpenROMS and Speeddos Kernals
// started c128-u36 conversion 19-Sept-2021

 
 
const int PowerLED = 4;      // Output Power LED
const int PowerLEDAlt = 13;  // Output Power LED (onboard LED)
const int A15 = 5;           // Output EPROM Address Line 15
const int A16 = 6;           // Output EPROM Address Line 16
const int A17 = 7;           // Output EPROM Address Line 17
const int ResetLine = 8;     // Output to /RESET line
const int EXROMLine = 3;     // Output the /EXROM line
const int RestoreKey = 9;    // Input Restore key
 
int RestoreDelay = 2000;  // 2000ms delay for restore key
const int FlashSpeed = 75; // LED Flash delay
 
const unsigned long repeatdelay = 500; // used for debouncing
 
int CurrentROM; // which rom is select (0-7)
int debouncecounter = 0;       // how many times we have seen new value (for debounce)
int debouncereading;
int debounce_count;
int RestoreHeld;
unsigned long TimeHeld; // amount of time Resotre is held down
 
int buttonDuration = 0; // for keeping track of how long restore is held down
boolean buttonHeld = 0; // for keeping track when you are holding down 
boolean Released = 0; // Keeping track when the restore key is released
boolean holdingRestore = 0; // Keeping track if you are holding restore
boolean resetSystem = 0; // keep track wheter to reset
 
int buttonInput; // used to return if restore is held
unsigned long time; //used to keep track of millis output
unsigned long htime; //used to keep track of millis output
unsigned long btime; //used to keep track of bounce millis output
 
void setup() {
  pinMode(PowerLED, OUTPUT);
  pinMode(PowerLEDAlt, OUTPUT);
  pinMode(A15, OUTPUT);
  pinMode(A16, OUTPUT);
  pinMode(A17, OUTPUT);
  pinMode(ResetLine, INPUT);
  pinMode(EXROMLine, INPUT);
  pinMode(RestoreKey, INPUT);
 
  digitalWrite(PowerLED, PowerLED); // turn on the power LED
 
  digitalWrite(ResetLine, LOW); // keep the system reset
  pinMode(ResetLine, OUTPUT); // switch reset line to OUTPUT so it can hold it low
  digitalWrite(ResetLine, LOW); // keep the system reset
 
  CurrentROM = EEPROM.read(1);
  SetSlot(CurrentROM);
  delay(200);
  pinMode(ResetLine, INPUT); // set the reset pin back to high impedance which releases the INPUT line
  delay(1000); // wait 1000ms 
  FlashLED(CurrentROM);  // flash the power LED to show the current state
  
  // all set!
}
 
void loop() {
  buttonInput = readButton(); delay(500);
  time = millis(); // load the number of milliseconds the arduino has been running into variable time
  if (buttonInput == 1) {
    if (!buttonHeld) {
      htime = time; TimeHeld = 0; buttonHeld = 1; } //restore button is pushed
    else { 
      TimeHeld = time - htime; } // button is being held down, keep track of total time held.
  }
  if (buttonInput == 0) {
    if (buttonHeld) {
      Released = 1; buttonHeld = 0; htime = millis(); TimeHeld = 0; //restore button not being held anymore
    } 
  }
  
  if (TimeHeld > RestoreDelay && !Released) { // do this when the time the button is held is longer than the delay and the button is released
    htime = millis();
    if (holdingRestore == 0) { FlashLED(CurrentROM); holdingRestore = 1; resetSystem = 1; } // first time this is run, so flash the LED with current slot and reset time held. Set the holding restore variable.
    else {
      if (CurrentROM < 7) { CurrentROM++; SaveSlot(CurrentROM); } // or you've already been holding restore, so increment the current ROM slot otherwise reset it to 0
      else { CurrentROM = 0; SaveSlot(CurrentROM); }
      if (TimeHeld > RestoreDelay) { TimeHeld = 0;}  // reset the time held
      FlashLED(CurrentROM); //flash the LED
    }
  }
  
  if (Released) {
    //if time held greater than restore delay, reset the system, set the current rom slot, reselt the time held and holding restore
    if (resetSystem) { // on do this if the reset system has been set above
      htime = millis();
      resetSystem = 0;
      holdingRestore = 0;
      Released = 0;
      digitalWrite(ResetLine, LOW); // keep the system reset
      digitalWrite(EXROMLine, LOW); // keep the EXROM line low
      pinMode(ResetLine, OUTPUT);
      pinMode(EXROMLine, OUTPUT);
      digitalWrite(ResetLine, LOW); // keep the system reset
      digitalWrite(EXROMLine, LOW); // keep the EXROM line low
      delay(50); // wait 50ms
      SetSlot(CurrentROM); // select the appropriate kernal ROM
      delay(200); // wait 200ms before releasing RESET line
      pinMode(ResetLine, INPUT); // set the reset pin back to high impedance so computer boots
      delay(300); // wait 300ms before releasing EXROM line
      pinMode(EXROMLine, INPUT); // set the reset pin back to high impedance so computer boots
      // additional reset added to work around RAM bug when running exrom reset on openroms or speeddos kernal
	  digitalWrite(ResetLine, LOW); // keep the system reset
      pinMode(ResetLine, OUTPUT);
      digitalWrite(ResetLine, LOW); // keep the system reset
      delay(200); // wait 200ms before releasing RESET line
      pinMode(ResetLine, INPUT); // set the reset pin back to high impedance so computer boots
    } else { //otherwise do nothing
      htime = millis(); Released = 0; resetSystem = 0; holdingRestore = 0;
    }
  }
// finished with loop  
}
 
int readButton() {
 if (!digitalRead(RestoreKey) && (millis() - btime >= repeatdelay)) {
  for(int i = 0; i < 10; i++)
    {
      debouncereading = !digitalRead(RestoreKey);
 
      if(!debouncereading && debouncecounter > 0)
      {
        debouncecounter--;
      }
      if(debouncereading)
      {
        debouncecounter++; 
      }
      // If the Input has shown the same value for long enough let's switch it
      if(debouncecounter >= debounce_count)
      {
        btime = millis();
        debouncecounter = 0;
        RestoreHeld = 1;
      }
    delay (10); // wait 10ms
    }
   } else {
    RestoreHeld = 0;
   }
return RestoreHeld;
}
 
 
void SaveSlot(int CurrentRomSlot) {
  // Save Current ROM selection (0-7) into EPROM
  EEPROM.write(1,CurrentRomSlot);
}
 
void FlashLED(int flashcount) {
    // Flash the LED to represent which ROM slot is selected
    switch (flashcount) {
    case 0:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
    case 1:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
    case 2:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
    case 3:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
	case 4:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
	  delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
	case 5:
	  digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
	  delay(FlashSpeed);
	  digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
	case 6:
digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
	  delay(FlashSpeed);
	  digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
     break;
	 case 7:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
	  delay(FlashSpeed);
	  digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      delay(FlashSpeed);
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
	 break;
	 
    default:
      digitalWrite(PowerLED, LOW);
      digitalWrite(PowerLEDAlt, LOW);
      delay(FlashSpeed);
      digitalWrite(PowerLED, HIGH);
      digitalWrite(PowerLEDAlt, HIGH);
      break;
  }
}
 
void SetSlot(int DesiredRomSlot) {
    // Select the actual ROM slot being used
    switch (DesiredRomSlot) {
    // Servant ROM 4.8.4
	case 0:
      digitalWrite(A15, LOW);
      digitalWrite(A16, LOW);
      digitalWrite(A17, LOW);
      break;
	// GEOS 1581
    case 1:
      digitalWrite(A15, HIGH);
      digitalWrite(A16, LOW);
      digitalWrite(A17, LOW);
      break;
	// BASIC 8
    case 2:
      digitalWrite(A15, LOW);
      digitalWrite(A16, HIGH);
      digitalWrite(A17, LOW);
      break;
	// KeyDOS
    case 3:
      digitalWrite(A15, HIGH);
      digitalWrite(A16, HIGH);
      digitalWrite(A17, LOW);
      break;
	// SuperChip A
    case 4:
      digitalWrite(A15, LOW);
      digitalWrite(A16, LOW);
      digitalWrite(A17, HIGH);
      break;
	// SuperChip B
    case 5:
      digitalWrite(A15, HIGH);
      digitalWrite(A16, LOW);
      digitalWrite(A17, HIGH);
      break;
	// Turbo Assembler
    case 6:
      digitalWrite(A15, LOW);
      digitalWrite(A16, HIGH);
      digitalWrite(A17, HIGH);
      break;
	// Diagnostics
    case 7:
      digitalWrite(A15, HIGH);
      digitalWrite(A16, HIGH);
      digitalWrite(A17, HIGH);
      break;
    default:
      digitalWrite(A15, LOW);
      digitalWrite(A16, LOW);
	  digitalWrite(A17, LOW);
      break;
  }
}