//rows
#define R1 20
#define R2 21
#define R3 2
#define R4 3
#define R5 4
#define R6 5
#define R7 6
#define R8 7

//columns
#define C1 9
#define C2 10
#define C3 11
#define C4 12
#define C5 13
#define C6 14
#define C7 15
#define C8 16

void setup() {
  Serial.begin(9600); // start serial

  // setup output ports
  for (int j = C1; j <= C8; j++) {
    pinMode(j, OUTPUT);
    digitalWrite(j, LOW);
  }

  for (int i = R3; i <= R8; i++) {
    pinMode(i, OUTPUT);
    digitalWrite(i, HIGH);
  }
  
  pinMode(R1, OUTPUT);
  digitalWrite(R1, HIGH);
  pinMode(R2, OUTPUT);
  digitalWrite(R2, HIGH);
}

void displayCharacter(byte character) {
  for (int row = R1; row <= R8; row++) {
    digitalWrite(row, LOW);

    for (int col = C1; col <= C8; col++) {
      digitalWrite(col, bitRead(character, col - C1));
    }

    delay(2); // Adjust delay as needed for your LED matrix
    for (int col = C1; col <= C8; col++) {
      digitalWrite(col, LOW);
    }

    digitalWrite(row, HIGH);
  }
}

void loop() {
  byte characters[] = {
    B00111110, // 0
    B00001100, // 1
    B01101101, // 2
    B01011101, // 3
    B00001111, // 4
    B01011011, // 5
    B01111011, // 6
    B00001101, // 7
    B01111111, // 8
    B01011111, // 9
    B01110111, // A
    B01111100, // B
    B00111001, // C
    B01011110, // D
    B01111001, // E
    B01110001  // F
  };

  for (int i = 0; i < 16; i++) {
    displayCharacter(characters[i]);
    delay(1000); // Adjust delay as needed between characters
  }
}