Hi, I was wondering if someone could help with this. I have a simple program, using Timer 4 to pull PWM Pin 13 high/low alternating every second. This is attached to a relay. When I compile the code, pin 13 outputs PWM - I hear the relay run at like at least 10Hz. However, when I power down and power up, I don't get the same thing, which is why I think it cant be the Setup(). I've attached the code. Quick note: I have recently discovered that Serial inside an ISR is a no-no; however I have left it in because maybe thats the cause? If anyone knows why this is happening, I would appreciate the advice.
#include "Arduino.h"
#define RelayPin 13
#define PIN_OUTPUT 3
//Initialise Pins
//Define Variables we'll be connecting to
double Setpoint, Input, Output;
int volts[9]={0,0,0,0,0,0,0,0,0};
static const int analog_pins[] = {A5,A6,A7,A8,A9,A10,A11,A12,A13};
boolean toggle4 = LOW;
void setup(){
Serial.begin(9600);
//set pins as outputs
pinMode(RelayPin, OUTPUT);
cli();//stop interrupts
//set timer4 interrupt at 1Hz
TCCR4A = 0;// set entire TCCR1A register to 0
TCCR4B = 0;// same for TCCR1B
TCNT4 = 0;//initialize counter value to 0
// set compare match register for 1hz increments
OCR4A = 15624/1;// = (16*10^6) / (1*1024) - 1 (must be <65536)
// turn on CTC mode
TCCR4B |= (1 << WGM12);
// Set CS12 and CS10 bits for 1024 prescaler
TCCR4B |= (1 << CS12) | (1 << CS10);
// enable timer compare interrupt
TIMSK4 |= (1 << OCIE4A);
sei();//allow interrupts
}//end setup
ISR(TIMER4_COMPA_vect){//timer1 interrupt 1Hz toggles pin 13 (LED)
//generates pulse wave of frequency 1Hz/2 = 0.5kHz (takes two cycles for full wave- toggle high then toggle low)
digitalWrite(RelayPin,toggle4);
Serial.print("s");
toggle4 = !toggle4;
for(int i=0; i<9; i++){
volts[i]=analogRead(analog_pins[i]);
Serial.print(volts[i]);
Serial.print(",");
}
Serial.write(13);
Serial.write(10);
}
void loop(){
//do other things here
}