failll.ino

#include <avr/interrupt.h>
#include <avr/io.h>
#include <stdint.h>


#define RADIOPIN 9
volatile char *ptr = NULL; // pointer to datastring buffer
volatile boolean sentence_needed = true;
char send_datastring[100] = "";
 

 
void setup() {
 pinMode(RADIOPIN, OUTPUT);
 setPwmFrequency(RADIOPIN, 1);
 initialise_interrupt();
}


void initialise_interrupt() 
{
  // initialize Timer1
  cli();          // disable global interrupts
  TCCR1A = 0;     // set entire TCCR1A register to 0
  TCCR1B = 0;     // same for TCCR1B

  OCR1A = F_CPU/16000-1; // DOMINOEX16

  TCCR1B |= (1 << WGM12);   // turn on CTC mode:
  // Set CS10 and CS12 bits for:
  TCCR1B |= (1 << CS10);
  TCCR1B |= (1 << CS12);
  // enable timer compare interrupt:
  TIMSK1 |= (1 << OCIE1A);
  sei();          // enable global interrupts
}



ISR(TIMER1_COMPA_vect)
{
  static uint8_t current_symbol = 0;
  static uint8_t current_char = 0x00;
  static uint8_t symbol_index = 0;
  
  uint8_t next_symbol;
  
  next_symbol = varicode[current_char][symbol_index++]; // get next symbol from varicode table
  
  current_symbol = (current_symbol + next_symbol + 2) % 18; // update for next symbol transmission
  analogWrite(RADIOPIN, current_symbol);

  // if reached end of either 2 or 3 symbol character, set index to 3 for executing next code
  if(symbol_index < 3 && !(varicode[current_char][symbol_index] & 0x08)) {
    symbol_index = 3;
  }
  
  // if we still have more symbols to send
  if(symbol_index != 3){
    return;
  }
  
  symbol_index = 0; // reset symbol index for next character
  

  if(sentence_needed == false && ptr){
    current_char = *ptr;
    ptr++;
    if(current_char){
      sentence_needed = false;
    }
    else{
      sentence_needed = true;
    }
  }
  else{
    sentence_needed = true;
  }
}
 
// the loop routine runs over and over again forever:
void loop() {
  
  if (sentence_needed){
    sprintf(send_datastring, "%s", "Hello World!");
    sentence_needed = true;
    ptr = send_datastring;
    sentence_needed = false;
  }
}

















 
void setPwmFrequency(int pin, int divisor) {
 byte mode;
 if(pin == 5 || pin == 6 || pin == 9 || pin == 10) {
 switch(divisor) {
 case 1:
 mode = 0x01;
 break;
 case 8:
 mode = 0x02;
 break;
 case 64:
 mode = 0x03;
 break;
 case 256:
 mode = 0x04;
 break;
 case 1024:
 mode = 0x05;
 break;
 default:
 return;
 }
 if(pin == 5 || pin == 6) {
 TCCR0B = TCCR0B & 0b11111000 | mode;
 }
 else {
 TCCR1B = TCCR1B & 0b11111000 | mode;
 }
 }
 else if(pin == 3 || pin == 11) {
 switch(divisor) {
 case 1:
 mode = 0x01;
 break;
 case 8:
 mode = 0x02;
 break;
 case 32:
 mode = 0x03;
 break;
 case 64:
 mode = 0x04;
 break;
 case 128:
 mode = 0x05;
 break;
 case 256:
 mode = 0x06;
 break;
 case 1024:
 mode = 0x7;
 break;
 default:
 return;
 }
 TCCR2B = TCCR2B & 0b11111000 | mode;
 }
}