//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() {
  // put your setup code here, to run once:
  Serial.begin(9600); //start serial
  //setup output ports
  //set row high and column low to ensure all LEDs are turned off at setup
  //Serial.println("Testing LED Matrix 8x8: ");
  for (int j = 9; j <= 16; j++) {
    pinMode(j, OUTPUT);
    digitalWrite(j, LOW);
  }

  for (int i = 2; i <= 7; i++) {
    pinMode(i, OUTPUT);
    digitalWrite(i, HIGH);
  }
  pinMode(20, OUTPUT);
  digitalWrite(20, HIGH);
  pinMode(21, OUTPUT);
  digitalWrite(21, HIGH);
}


void loop() {
  //turn on 
  // coloumn 
   digitalWrite(C1, HIGH);
   digitalWrite(C2, HIGH);
   digitalWrite(C3, HIGH);
   digitalWrite(C4, HIGH);
   digitalWrite(C5, HIGH);
   digitalWrite(C6, HIGH);
   digitalWrite(C7, HIGH);
   digitalWrite(C8, HIGH);

 //raw  
   digitalWrite(R1, LOW);
   digitalWrite(R2, LOW);
   digitalWrite(R3, LOW);
   digitalWrite(R4, LOW);
   digitalWrite(R5, LOW);
   digitalWrite(R6, LOW);
   digitalWrite(R7, LOW);
   digitalWrite(R8, LOW);

   delay(1000);
  
  
  // turn off 
   digitalWrite(R1, HIGH);
   digitalWrite(R2, HIGH);
   digitalWrite(R3, HIGH);
   digitalWrite(R4, HIGH);
   digitalWrite(R5, HIGH);
   digitalWrite(R6, HIGH);
   digitalWrite(R7, HIGH);
   digitalWrite(R8, HIGH);

  delay(1000);

}