// thermo3_skel.c
// R. Traylor
// 11.15.2011 (revised 11.18.2013)

//Demonstrates basic functionality of the LM73 temperature sensor
//Uses the mega128 board and interrupt driven TWI.
//PD0 is SCL, PD1 is SDA. 

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <string.h>
#include <stdlib.h>
#include "hd44780.h"
#include "lm73_functions.h"
#include "twi_master.h"

char    lcd_string_array[16];  //holds a string to refresh the LCD
uint8_t i;                     //general purpose index

extern uint8_t ................
extern uint8_t ................

//********************************************************************
//                            spi_init                               
//Initalizes the SPI port on the mega128. Does not do any further    
// external device specific initalizations.                          
//********************************************************************
void spi_init(void){
  DDRB |=  0x07;  //Turn on SS, MOSI, SCLK
  //mstr mode, sck=clk/2, cycle 1/2 phase, low polarity, MSB 1st, 
  //no interrupts, enable SPI, clk low initially, rising edge sample
  SPCR=(1<<SPE) | (1<<MSTR); 
  SPSR=(1<<SPI2X); //SPI at 2x speed (8 MHz)  
 }//spi_init

/***********************************************************************/
/*                                main                                 */
/***********************************************************************/
int main ()
{     
uint16_t lm73_temp;  //a place to assemble the temperature from the lm73

................ //initalize SPI 
................ //initalize LCD (see: lcd_functions.h)
................ //initalize TWI (see: twi_master.h)  

sei();           //enable interrupts before entering loop

//set LM73 mode for reading temperature by loading pointer register
................ //load lm73_wr_buf[0] with temperature pointer address
................ //start the TWI write process
_delay_ms(2);    //wait for the xfer to finish

clear_display(); //clean up the display

while(1){          //main while loop
  _delay_ms(100);} //tenth second wait
  clear_display();                  //wipe the display
  ................ //read temperature data from LM73 (2 bytes) 
  _delay_ms(2);    //wait for it to finish
  ................ //save high temperature byte into lm73_temp
  ................ //shift it into upper byte 
  ................ //"OR" in the low temp byte to lm73_temp 
  ................ //convert to string in array with itoa() from avr-libc                           
  ................ //send the string to LCD (lcd_functions)
  } //while
} //main

//for binary output:
//itoa((int)lm73_temp, lcd_string_array, 2);
//string2lcd(lcd_string_array);