AVR Freaks

//file rxintuart.c
//rx int on uart
//Oct 10 04 bob g initial edit
//Sept 9 07 Bob G recompile with v7.13

#include 
#include 
#include 
#include 

//------------------------
#define BUFSIZ 64
char rxbuf[BUFSIZ];
char rxindx,rxondx;

//-----------------------
void port_init(void){
  PORTA = 0xFF;
  DDRA  = 0xFF; 
 
  PORTB = 0xFF; 
  DDRB  = 0xFF; 
	 
  PORTC = 0xFF; 
  DDRC  = 0xFF; 
 
  PORTD = 0xFF; 
  DDRD  = 0xFF; 
}

//---------------------
//UART0 initialisation
// desired baud rate: 38400
// actual: baud rate:38462 (0.2%)
// char size: 8 bit
// parity: Disabled
void uart0_init(void){
  UCSRB = 0x00; //disable while setting baud rate
  UCSRA = 0x00;
  UCSRC = 0x06;
  UBRRL = 0x19; //set baud rate lo
  UBRRH = 0x00; //set baud rate hi
  UCSRB = 0x98;
}

//---------------------
void init_devices(void){
  //stop errant interrupts until set up
  CLI(); //disable all interrupts
  port_init();
  uart0_init();

  MCUCR = 0x00; //no ext mem
  SEI(); //re-enable interrupts
  //all peripherals are now initialised
}

//-------------------------
unsigned char kbhit(void){
//return nonzero if char waiting  intr version
unsigned char b;

  b=rxindx != rxondx;
  return b;
}

//-----------------------
int getchar(void){
//intr version... overrides version in library
char c;

  while(!kbhit()){}; //wait for char
  c=rxbuf[rxondx++]; //get char from rxbuf
  if(rxondx > BUFSIZ-1) rxondx=0;
  return c;  
}

//------------------------------
#pragma interrupt_handler uart_rx_isr:iv_USART_RX
void uart_rx_isr(void){
//uart has received a character in UDR  mega16version
char c;

  c=UDR;             //get char from usart
  rxbuf[rxindx++]=c; //put char in rxbuf
  if(rxindx > BUFSIZ-1) rxindx=0;  
}

//-----------------------
int putc(char c){
//put char to usart0... dont add lf after cr   mega16 version

  while((UCSRA & 0x20)==0){};	//0x20 is UDRE0. ==0 means data register full
  UDR=c; //send char
  return c;
}

//----------------------  
int putchar(char c)	{
//adds lf after cr

  if(c=='\n'){
    putc('\r');
  }  
  putc(c);
  return c;
}

//--------------
void echochars(void){
//echo chars out uart
char c;

  cprintf("echo chars  ctl-e to exit\n");
  while(1){
    if(kbhit()){
	    c=getchar();
	    if(c==0x05) return;
	    putc(c);
	  }
  }
}

//----------------
void menu(void){

  cprintf("cmds:\n");
  cprintf(" e echochars\n");
}

//----------------
void main(void){
//main program
char c;

  init_devices();
  cprintf("rxintuart Sept 9 07\n");
  menu();
  while(1){
	  c=getchar();
	  switch(c){
	    case 'e': echochars(); break;
	  }
  }  
}
//--------eof------------