CodeVisionAVR Rx ISR

#include <mega88.h>

//8MHz

// Declare your global variables here

#define DATA_REGISTER_EMPTY (1<<UDRE0)

#define RX_COMPLETE (1<<RXC0)

#define FRAMING_ERROR (1<<FE0)

#define PARITY_ERROR (1<<UPE0)

#define DATA_OVERRUN (1<<DOR0)

// USART Receiver buffer

#define RX_BUFFER_SIZE0 8

char rx_buffer0[RX_BUFFER_SIZE0];

#if RX_BUFFER_SIZE0 <= 256

unsigned char rx_wr_index0=0,rx_rd_index0=0;

#else

unsigned int rx_wr_index0=0,rx_rd_index0=0;

#endif

#if RX_BUFFER_SIZE0 < 256

unsigned char rx_counter0=0;

#else

unsigned int rx_counter0=0;

#endif

// This flag is set on USART Receiver buffer overflow

bit rx_buffer_overflow0;

// USART Receiver interrupt service routine

interrupt [USART_RXC] void usart_rx_isr(void)

{

char status,data;

status=UCSR0A;

data=UDR0;

if ((status & (FRAMING_ERROR | PARITY_ERROR | DATA_OVERRUN))==0)

   {

   rx_buffer0[rx_wr_index0++]=data;

#if RX_BUFFER_SIZE0 == 256

   // special case for receiver buffer size=256

   if (++rx_counter0 == 0) rx_buffer_overflow0=1;

#else

   if (rx_wr_index0 == RX_BUFFER_SIZE0) rx_wr_index0=0;

   if (++rx_counter0 == RX_BUFFER_SIZE0)

      {

      rx_counter0=0;

      rx_buffer_overflow0=1;

      }

#endif

   }

}

#ifndef _DEBUG_TERMINAL_IO_

// Get a character from the USART Receiver buffer

#define _ALTERNATE_GETCHAR_

#pragma used+

char getchar(void)

{

char data;

while (rx_counter0==0);

data=rx_buffer0[rx_rd_index0++];

#if RX_BUFFER_SIZE0 != 256

if (rx_rd_index0 == RX_BUFFER_SIZE0) rx_rd_index0=0;

#endif

#asm("cli")

--rx_counter0;

#asm("sei")

return data;

}

#pragma used-

#endif

// Standard Input/Output functions

#include <stdio.h>

void main(void)

{

// Declare your local variables here

// Crystal Oscillator division factor: 1

#pragma optsize-

CLKPR=(1<<CLKPCE);

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

#ifdef _OPTIMIZE_SIZE_

#pragma optsize+

#endif

// Input/Output Ports initialization

// Port B initialization

// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 

DDRB=(0<<DDB7) | (0<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);

// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 

PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) | (0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization

// Function: Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 

DDRC=(0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) | (0<<DDC1) | (0<<DDC0);

// State: Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 

PORTC=(0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) | (0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization

// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 

DDRD=(0<<DDD7) | (0<<DDD6) | (0<<DDD5) | (0<<DDD4) | (0<<DDD3) | (0<<DDD2) | (0<<DDD1) | (0<<DDD0);

// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 

PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) | (0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// USART initialization

// Communication Parameters: 8 Data, 1 Stop, No Parity

// USART Receiver: On

// USART Transmitter: Off

// USART0 Mode: Asynchronous

// USART Baud Rate: 9600

UCSR0A=(0<<RXC0) | (0<<TXC0) | (0<<UDRE0) | (0<<FE0) | (0<<DOR0) | (0<<UPE0) | (0<<U2X0) | (0<<MPCM0);

UCSR0B=(1<<RXCIE0) | (0<<TXCIE0) | (0<<UDRIE0) | (1<<RXEN0) | (0<<TXEN0) | (0<<UCSZ02) | (0<<RXB80) | (0<<TXB80);

UCSR0C=(0<<UMSEL01) | (0<<UMSEL00) | (0<<UPM01) | (0<<UPM00) | (0<<USBS0) | (1<<UCSZ01) | (1<<UCSZ00) | (0<<UCPOL0);

UBRR0H=0x00;

UBRR0L=0x33;

// Global enable interrupts

#asm("sei")

while (1)

      {

      // Place your code here

      }

}

DDRB=(0<<DDB7) | (0<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);

DDRB = 0;