Lamont's PWM code

/*
 * 2009-03-24, pager motor test, lamont lucas
 *
 */

// define the pins used to run the shift registers 
int enable_low = 5;  //enable outputs, low = on
int serial_in  = 6; 
int ser_clear_low = 7;  //pulse low to zero out the shift buffer
int RCK  = 9;  //RCK, push the serial buffer to the outputs
int SRCK = 10;  //

// analog definitions.
// int potPin = 23;    // select the input pin for the potentiometer

void setup() {
  pinMode(enable_low, OUTPUT);  // set shift register pins as outputs
  pinMode(serial_in, OUTPUT);
  pinMode(ser_clear_low, OUTPUT);
  pinMode(RCK, OUTPUT);
  pinMode(SRCK, OUTPUT);
  
  //more test
  //pinMode(11, OUTPUT);
  
  // use some serial for debugging
  Serial.begin(9600);
  Serial.println("Setting up board");
  
  // make sure we start out all off
  digitalWrite(enable_low, HIGH);
  // this should wipe out the serial buffer on the shift register
  digitalWrite(ser_clear_low, LOW);
  delay(100);   //delay in ms
  
  // the TPIC6b595 clocks work on a rising edge, so make sure they're low to start.
  digitalWrite(RCK, LOW);
  digitalWrite(SRCK, LOW);
  
  digitalWrite(ser_clear_low, HIGH);   //we are now clear to write into the serial buffer

  Serial.println("Board is setup");
}


void loop() {
  
  //test statement
  analogWrite(17, 200);
  //raise enable high to disable outputs
  digitalWrite(enable_low, HIGH);
  
  delayMicroseconds(100);  //slow and steady
  //shiftOut(serial_in, SRCK, LSBFIRST, B01010101);
  shiftOut(serial_in, SRCK, LSBFIRST, B11111111);
  //pulse RCK to pop that into the outputs
  delayMicroseconds(100);
  digitalWrite(RCK, HIGH);
  delayMicroseconds(100);
  digitalWrite(RCK, LOW);
  
  for (int i=150; i <= 250; i += 10) {
    Serial.print("Using PWM value of ");
    Serial.println(i);
    //pwm the enable (255 = 0v, 0 = 5v)
    analogWrite(enable_low, i);
    delay(250);
  }
}