ArduinoProMicroC64SwitchlessRomSelect.ino

// This is a firmware for making an arduino pro micro into a switchless rom controller for selecting address pins on
// a 64 kib rom for kernals and a 16 kib rom for charsets in a c64.

// It also does a simple RGB thingy, adjust the ledMin to adjust brightness, depends on your led, resistors and preference for eye-burning.
// I used 5k3 resisters on my RGB led, it's pretty sensitive
const int ledMin=128;

int r=ledMin;
int g=ledMin+21;
int b=ledMin+60;

const int slowness = 30; // adjust how fast it rotates the rgb colors, smaller = faster, minimum 1
// nothing more should need tweaking

#include <EEPROM.h>

const int restorePin = A0; // hooks to the ~RESTORE line
const int kernA13 = 16;    // kernal rom, address 13 pin, goes to pin 16 on the pro micro
const int kernA14 = 14;
const int kernA15 = 15;
const int charA13 = 19; // character rom, address 13 pin goes to pin A1 on the micro
const int charA14 = 20; // Pin A2

const int LEDR = 9;
const int LEDG = 5;
const int LEDB = 6;

const int LEDPWR = 10;

void load() {
  int chkA = EEPROM.read(0);
  int chkB = EEPROM.read(1);
  int chkC = EEPROM.read(2);
  int kernSetting = EEPROM.read(3);
  int charSetting = EEPROM.read(4);

  if( ! (chkA == 'C' && chkB == '6' && chkC == '4')) {
    kernSetting=0;
    charSetting=1;
  }
  
  digitalWrite( kernA13, (kernSetting&(1<<0))>>0 );
  digitalWrite( kernA14, (kernSetting&(1<<1))>>1 );
  digitalWrite( kernA15, (kernSetting&(1<<2))>>2 );

  digitalWrite( charA13, (charSetting&(1<<0))>>0 );
  digitalWrite( charA14, (charSetting&(1<<1))>>1 );
    
}


void set(int ker, int cha) {
  EEPROM.write(0,'C');
  EEPROM.write(1,'6');
  EEPROM.write(2,'4');
  EEPROM.write(3, (char)ker);
  EEPROM.write(4, (char)cha);
  load();
}

void setup() {

  pinMode(restorePin, INPUT);
  analogReference(DEFAULT);

  pinMode(kernA13, OUTPUT);
  pinMode(kernA14, OUTPUT);
  pinMode(kernA15, OUTPUT);
  pinMode(charA13, OUTPUT);
  pinMode(charA14, OUTPUT);

  pinMode(LEDR, OUTPUT);
  pinMode(LEDG, OUTPUT);
  pinMode(LEDB, OUTPUT);

  pinMode(LEDPWR, OUTPUT);
  digitalWrite(LEDPWR, HIGH);


  load();
  
}

// 10 ms
bool btn() {
    delay(2);
    int sum=analogRead(restorePin);
    delay(2);
    sum+=analogRead(restorePin);
    delay(2);
    sum+=analogRead(restorePin);
    delay(2);
    sum+=analogRead(restorePin);
    delay(2);
    sum+=analogRead(restorePin);
    return ( sum < 500);
}

// if down for milliseconds.
bool btnDn(int n) {
  int t = 0;


  while(btn()) {
    t+=10;
    if(t<n) {
      analogWrite(LEDR, ledMin);
      analogWrite(LEDG, 255);
      analogWrite(LEDB, 255);
    } else {
      return true;
    }
  }
  return false;
}

void debounce() {
  while(btn()) {
    delay(50);
  }
}



int rd=1;
int gd=1;
int bd=1;

int fd=0;

void loop() {

  fd++;
  if(fd==slowness) {
      fd=0;
    r+=rd;
    if(r<ledMin) {
      rd=1;
    }
    if(r>254) {
      rd=-1;
    }
  
    g+=gd;
    if(g<ledMin) {
      gd=1;
    }
    if(g>254) {
      gd=-1;
    }
  
    b+=bd;
    if(b<ledMin) {
      bd=1;
    }
    if(b>254) {
      bd=-1;
    }
  }


  analogWrite(LEDR, r);
  analogWrite(LEDG, g);
  analogWrite(LEDB, b);
  
  int ker=0;
  int cha=0;

  int act;

  if(btnDn(2000)) {
    analogWrite(LEDR, 255);
    analogWrite(LEDG, ledMin);
    analogWrite(LEDB, 255);
    debounce();
    analogWrite(LEDR, 255);
    analogWrite(LEDG, 255);
    analogWrite(LEDB, 255);
      

    act=2000;
    while(act) {
      act-=10;
      if(btn()) {
        debounce();
        ker++;
        if(ker>7) {
          ker=0;
        }
        switch(ker) {
          case 0:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, 255);
          break;
          case 1:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, 255);
          break;
          case 2:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, ledMin);
          break;
          case 3:
            analogWrite(LEDR, ledMin);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, 255);
          break;
          case 4:
            analogWrite(LEDR, ledMin);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, ledMin);
          break;
          case 5:
            analogWrite(LEDR, ledMin);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, 255);
          break;
          case 6:
            analogWrite(LEDR, ledMin);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, ledMin);
          break;
          case 7:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, ledMin);
          break;

        }
        act=2000;
      }
    }


    for(int i=0; i < 5; i++) {
      analogWrite(LEDR, ledMin);
      analogWrite(LEDG, ledMin);
      analogWrite(LEDB, ledMin);
      delay(100);
      analogWrite(LEDR, 255);
      analogWrite(LEDG, 255);
      analogWrite(LEDB, 255);
      delay(100);
    }
    analogWrite(LEDR, 255);
    analogWrite(LEDG, 255);
    analogWrite(LEDB, 255);
    

    act=2000;
    while(act) {
      act-=10;
      if(btn()) {
        debounce();
        cha++;
        if(cha>3) {
          cha=0;
        }
        switch(cha) {
          case 0:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, 255);
          break;
          case 1:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, 255);
          break;
          case 2:
            analogWrite(LEDR, 255);
            analogWrite(LEDG, ledMin);
            analogWrite(LEDB, ledMin);
          break;
          case 3:
            analogWrite(LEDR, ledMin);
            analogWrite(LEDG, 255);
            analogWrite(LEDB, 255);
          break;

        }
        act=2000;
      }
    }

    for(int i=0; i < 5; i++) {
      analogWrite(LEDR, ledMin);
      analogWrite(LEDG, ledMin);
      analogWrite(LEDB, ledMin);
      delay(100);
      analogWrite(LEDR, 255);
      analogWrite(LEDG, 255);
      analogWrite(LEDB, 255);
      delay(100);
    }

    set(ker,cha);    
  }

}