//UART Example for inclass coding
//Roger Traylor 12.4.12
//Connect two mega128 boards via rs232 and they should send to each
//other a message and a sequence number.
//
//Change the message you send to your partner for checkoff.
//
//You can test this code by a "loopback" if you connect rx to tx
//on the DB9 connector.
//

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

uint8_t           i;
volatile uint8_t  rcv_rdy;
char              rx_char; 
char              lcd_str_array[16];  //holds string to send to lcd
uint8_t           send_seq=0;         //transmit sequence number
char              lcd_string[3];      //holds value of sequence number

void spi_init(void){
  DDRB   = DDRB | 0x07;           //Turn on SS, MOSI, SCLK pins
  SPCR  |= (1<<SPE) | (1<<MSTR);  //set up SPI mode
  SPSR  |= (1<<SPI2X);            //run at double speed 
}//spi_init    

int main(){
  DDRF |= 0x08; //lcd strobe bit
  uart_init();  
  spi_init();
  lcd_init();
  clear_display();
  cursor_home();

  sei();
  while(1){
//**************  start rcv portion ***************
      if(rcv_rdy==1){
        string2lcd(lcd_str_array);  //write out string if its ready
        rcv_rdy=0;
        cursor_home();
    }//if 
//**************  end rcv portion ***************

//**************  start tx portion ***************
    uart_puts("Hi! Dilbert: ");        //send message
    itoa(send_seq,lcd_string,10);      //send sequence number
    uart_puts(lcd_string);
    uart_putc('\0');                   //mark end of string with null char
    for(i=0;i<=9;i++){_delay_ms(100);} //one sec. delay
    send_seq++;
    send_seq=(send_seq%20);
//**************  end tx portion ***************
  }//while
}//main

ISR(USART0_RX_vect){
static  uint8_t  i;
  rx_char = UDR0;              //get character
  lcd_str_array[i++]=rx_char;  //store in array 
 //if entire string has arrived, set flag, reset index
  if(rx_char == '\0'){
    rcv_rdy=1; 
    lcd_str_array[--i]  = (' ');     //clear the count field
    lcd_str_array[i+1]  = (' ');
    lcd_str_array[i+2]  = (' ');
    i=0;  
  }
}
//************************************//