232.c

本程序是一儿歌单片机与电脑的串行通讯程序

//ICC-AVR application builder : 2008-1-21 下午 01:55:06
// Target : M128
// Crystal: 8.0000Mhz

#include <iom128v.h>
#include <macros.h>

#define UDRE  5
#define RXC  7


void port_init(void)
{
 PORTA = 0x00;
 DDRA  = 0x00;
 PORTB = 0x00;
 DDRB  = 0x00;
 PORTC = 0x00; //m103 output only
 DDRC  = 0x00;
 PORTD = 0x00;
 DDRD  = 0x00;
 PORTE = 0x00;
 DDRE  = 0x00;
 PORTF = 0x00;
 DDRF  = 0x00;
 PORTG = 0x00;
 DDRG  = 0x00;
}

//UART0 initialize
// desired baud rate: 9600
// actual: baud rate:9615 (0.2%)
// char size: 8 bit
// parity: Disabled
void uart0_init(void)
{
 UCSR0B = 0x00; //disable while setting baud rate
 UCSR0A = 0x00;
 UCSR0C = 0x06;
 UBRR0L = 0x33; //set baud rate lo
 UBRR0H = 0x00; //set baud rate hi
 UCSR0B = 0xF8;
}

#pragma interrupt_handler uart0_rx_isr:19
void uart0_rx_isr(void)
{
 //uart has received a character in UDR
}

#pragma interrupt_handler uart0_udre_isr:20
void uart0_udre_isr(void)
{
 //character transferred to shift register so UDR is now empty
}

#pragma interrupt_handler uart0_tx_isr:21
void uart0_tx_isr(void)
{
 //character has been transmitted
}

//call this routine to initialize all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 XDIV  = 0x00; //xtal divider
 XMCRA = 0x00; //external memory
 port_init();
 uart0_init();

 MCUCR = 0x00;
 EICRA = 0x00; //extended ext ints
 EICRB = 0x00; //extended ext ints
 EIMSK = 0x00;
 TIMSK = 0x00; //timer interrupt sources
 ETIMSK = 0x00; //extended timer interrupt sources
 SEI(); //re-enable interrupts
 //all peripherals are now initialized
}

//
void USART_Transmit( unsigned char data )
{
/* 等待发送缓冲器为空 */
while (!(UCSR0A & (1<<UDRE)))
//while (!(UCSR0A & 0x20))
;
/* 将数据放入缓冲器，发送数据*/
UDR0 = data;
}

unsigned char USART_Receive( void )
{
/* 等待接收数据*/
while (!(UCSR0A & (1<<RXC)))
//while (!(UCSR0A & 0x80))
;
/* 从缓冲器中获取并返回数据*/
return UDR0;
}
//

  unsigned char data=0x11;
  
void main(void)
{
  unsigned char temp;
 init_devices();
 //insert your functional code here...
   temp= UCSR0A;
   data=USART_Receive();
   
 if(data==0x00)
 {
 data=0xaa;
 USART_Transmit(data );
 }
 else
 if(data==1)
  USART_Transmit(0xee);
  else
    USART_Transmit(0xff);

 while(1);
  
}