/**
 * Composite pal adapter test.
 * This sketch makes an Arduino send test data to tha Pat80 composite video pal adapter.
 * Connect the video adapter directly to Arduino
 */

const byte CLK = 11;   // output active low
const byte RS = 12;   // output low = DATA register, high = COMMAND register
const byte BUSY = 13;   // Input, Active low
// DATA BUS (Output, active high): 3, 4, 5, 6, 7, 8, 9, 10;

void setup() {
  DDRD = DDRD | B11111000; // Port D (arduino pins 3 to 7) is output. In or to preserve serial pins and interrupt pin
  DDRB = B00000111; // Port B (0,1,2) = pins 8,9,10 output
  pinMode(CLK, OUTPUT);
  pinMode(RS, OUTPUT);
  pinMode(BUSY, INPUT);

  digitalWrite(CLK, HIGH);  // Inactive clock
}

void loop() {
  delay(1000);
  send();
}

void send() {
    // Random char
    char c = random(32, 126);
    // Wait for BUSY to become inactive (HIGH)
    //while(digitalRead(BUSY) == LOW) {}

    // Split byte to two parts and write to ports
    PORTD = c << 3;
    PORTB = c >> 5;

    // Clock pulse
    digitalWrite(CLK, LOW);
    delay(100);
    digitalWrite(CLK, HIGH);
}