Svenska ElektronikForumet

Kod: Markera allt

//Serial communication example for Attiny2313 and avr-gcc.
//Mats Nordwinger 2009-01-25, Released - Under GPL 8)
#include <avr/io.h>
#include <avr/interrupt.h>

// Prototypes
void InitUSART (unsigned char baudrate);
void InitInterrupt();
void WriteString(char *car);
unsigned char ReceiveByte (void);
void TransmitByte (unsigned char data);
void Delay(int msek);

// Interrupt on input buffer byte complete.
ISR(USART_RX_vect){ 
	TransmitByte (ReceiveByte () + 1);        // Echo the received character + 1. 
	PORTB |= (0x01 << 0);					// LED on, to indicate recieved char.
}

// Main program
int main (void){

	char hello[] = "Hello World! ";

  	InitUSART (207); // Set the baudrate to 2400 bps using 8MHz
  	InitInterrupt();

	DDRB=0xFF; //Assign portB to output
	PORTB=0x00; //All portB bits to zero
	    
  	while (1){
	  // Blink LED, just to tell someting's going on
      Delay(500);
	  PORTB |= (0x01 << 0);
	  Delay(500);
	  PORTB &= ~(0x01 << 0);
	  WriteString(hello);
	  TransmitByte(0x0A); // LF
	  TransmitByte(0x0D); // CR
    }
} // End main program

// Initialize USART
void InitUSART (unsigned char baudrate){
  // Set the baud rate
  UBRRL = baudrate;
  //Enable Transmitter and Receiver and Interrupt on receive complete
  UCSRB=(1<<RXEN)|(1<<TXEN)|(1<<RXCIE);
  // 8 data bits, 1 stop bit
  UCSRC = (1 << UCSZ1) | (1 << UCSZ0);
}

// Enable global interrupt.
void InitInterrupt(){
	cli(); //Disable interrupt
	sei(); //Enable interrupt
}

// This function sends strings to USART
void WriteString(char *car){   
     while(*car != '\0'){
                TransmitByte(*car);
                car++;              
                }
     }

// Read USART incoming data
unsigned char ReceiveByte (void){
  // Wait for incomming data
  while (!(UCSRA & (1 << RXC)));
  // Return the data
  return UDR;
}

// Write data to USART outpu buffer
void TransmitByte (unsigned char data){
  // Wait for empty transmit buffer
  while (!(UCSRA & (1 << UDRE)));
  // Start transmission
  UDR = data;
}

//Delay "calibrated" for 8MHz
void Delay(int msek){
	unsigned int i=0, j=0;
	for(j=0;j<msek;j++){
		for(i=0;i<350;i++){
		}
	}
};