// Code to grab the time from 
// an ESP8266 chip (represented as an integer)
// using serial communications
// and receive on an attiny44
// 
// get_char, put_char and elements from the preamble taken from code by Neil Gershenfeld
//
//
//
// Rahul Naidoo 
// 2016
// HTM[a]A





#include <avr/io.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <string.h>


#define output(directions,pin) (directions |= pin) // set port direction for output
#define input(directions,pin) (directions &= (~pin)) // set port direction for input
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define bit_delay_time 100 // bit delay for 9600 with overhead
#define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay
#define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay
#define pause_delay() _delay_ms(10) //  pause between sending ints
#define char_delay() _delay_ms(10) // char delay


char cambridgetime(char num){
if (num == 'A') {
	return(19);
}
else if (num == 'B') {
	return(20);
}
else if (num == 'C') {
	return(21);
}
else if (num == 'D') {
	return(22);
}
else if (num == 'E') {
	return(23);
}
else if (num == 'F') {
	return(0);
}
else if (num == 'G') {
	return(1);
}
else if (num == 'H') {
	return(2);
}
else if (num == 'I') {
	return(3);
}
else if (num == 'J') {
	return(4);
}
else if (num == 'K') {
	return(5);
}
else if (num == 'L') {
	return(6);
}
else if (num == 'M') {
	return(7);
}
else if (num == 'N') {
	return(8);
}
else if (num == 'O') {
	return(9);
}
else if (num == 'P') {
	return(10);
}
else if (num == 'Q') {
	return(11);
}
else if (num == 'R') {
	return(12);
}
else if (num == 'S') {
	return(13);
}
else if (num == 'T') {
	return(14);
}
else if (num == 'U') {
	return(15);
}
else if (num == 'V') {
	return(16);
}
else if (num == 'W') {
	return(17);
}
else if (num == 'X') {
	return(18);
}
else {
	return(28);
}
}

void get_char(volatile unsigned char *pins, unsigned char pin, char *rxbyte) {
   //
   // read character into rxbyte on pins pin
   //    assumes line driver (inverts bits)
   //
   *rxbyte = 0;
   while (pin_test(*pins,pin))
      //
      // wait for start bit
      //
      ;
   //
   // delay to middle of first data bit
   //
   half_bit_delay();
   bit_delay();
   //
   // unrolled loop to read data bits
   //
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 0);
   else
      *rxbyte |= (0 << 0);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 1);
   else
      *rxbyte |= (0 << 1);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 2);
   else
      *rxbyte |= (0 << 2);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 3);
   else
      *rxbyte |= (0 << 3);
   bit_delay(); 
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 4);
   else
      *rxbyte |= (0 << 4);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 5);
   else
      *rxbyte |= (0 << 5);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 6);
   else
      *rxbyte |= (0 << 6);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 7);
   else
      *rxbyte |= (0 << 7);
   //
   // wait for stop bit
   //
   bit_delay();
   half_bit_delay();
   }


   void put_char(volatile unsigned char *port, unsigned char pin, char txchar) {
   //
   // send character in txchar on port pin
   //    assumes line driver (inverts bits)
   //
   // start bit
   //
   clear(*port,pin);
   bit_delay();
   //
   // unrolled loop to write data bits
   //
   if bit_test(txchar,0)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,1)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,2)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,3)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,4)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,5)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,6)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,7)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   //
   // stop bit
   //
   set(*port,pin);
   bit_delay();
   //
   // char delay
   //
   bit_delay();
   }
	



int main(void) {

static char Timeint;

  CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //

DDRA = 0b00001001;  

set(PORTA, (1 << PA3)); // set the input pin 
//input(0b00001001, (1 << PA2)); 
input(DDRA, (1 << PA3)); 

set(PORTA, (1 << PA1)); //set the output pin
//output(0b00001001, (1 << PA0));
output(DDRA, (1 << PA1));


while (1) {

if ((PINA & 0b00001000) == 0 ) {
get_char(&PINA, (1 << PA3), &Timeint);
char newchar = cambridgetime(Timeint); // convert the time
      put_char(&PORTA, (1 << PA1), 1);
      char_delay();
      put_char(&PORTA, (1 << PA1), 2);
      char_delay();
      put_char(&PORTA, (1 << PA1), 3);
      char_delay();
      put_char(&PORTA, (1 << PA1), 4);
      char_delay();
put_char(&PORTA, (1 << PA1), newchar);
pause_delay();
put_char(&PORTA, (1 << PA1), newchar);
pause_delay();
put_char(&PORTA, (1 << PA1), newchar);
pause_delay();
}





}


return(0);

}