串口错码怎么解决？高手来看下。

只看该作者 · 2009-11-26 14:13

用串口调试软件发数据给单片机，单片机再把收到的数据发出去，用串口调试软件查看单片机发送的数据.

结果发现串口调试软件接收到的数据很多和发出去的不一样，搞不清楚是怎么回事了，懂的人指导一下。

波特率1200，无校验，数据位8，停止位1 。

// Target : M16
// Crystal: 8.0000Mhz
//AVR单片机atmega16串口中断接收和发送程序。接收到字符后再发送出去
#include <iom16v.h>
#include <macros.h>
unsigned char com_in_buf[1];
void port_init(void)
{
PORTA = 0x00;
DDRA  = 0x00;
PORTB = 0x00;
DDRB  = 0xFF;
PORTC = 0x00; //m103 output only
DDRC  = 0x00;
PORTD = 0xFF;
DDRD  = 0xFF;
}

//UART0 initialize
// desired baud rate: 1200
// actual: baud rate:1200 (0%)
// char size: 8 bit
// parity: Disabled
void uart0_init(void)
{
UCSRB = 0x00; //disable while setting baud rate
UCSRA = 0x00;
UCSRC = BIT(URSEL) | 0x06;
UBRRL = 0xF9; //set baud rate lo
UBRRH = 0x00; //set baud rate hi
UCSRB = 0x98;
}

void send_data(unsigned char back)
{
  while( !( UCSRA & (1<<UDRE)) ) ;
  UDR=back;
}

#pragma interrupt_handler uart0_rx_isr:12
void uart0_rx_isr(void)
{
//uart has received a character in UDR
com_in_buf[0]=UDR;
send_data(com_in_buf[0]);
}

//call this routine to initialize all peripherals
void init_devices(void)
{
//stop errant interrupts until set up
CLI(); //disable all interrupts
port_init();
uart0_init();

MCUCR = 0x00;
GICR  = 0x00;
TIMSK = 0x00; //timer interrupt sources
SEI(); //re-enable interrupts
//all peripherals are now initialized
}

void main(void)
{
  char j;
  init_devices();
  while(1)
  {
for(j=1;j<100;j++)
  ;
  }
}