avr串口程序例子----查询模式.txt

AVR306串口程序例子----查询模式 Application Note AVR306 * Polled mode driver for UART, this is the similar to

AVR串口程序例子----查询模式发布时间：2007-04-27 关键字： 查询 模式 例子 程序 the void data baudrate for unsigned * Code adapted from Atmel AVR Application Note AVR306
* Polled mode driver for UART, this is the similar to the
* library default putchar() and getchar() in ICCAVR
*/
#include <io8515.h>
#include <macros.h>
#include "uart.h"

/* initialize UART */
void InitUART( unsigned char baudrate )
    {
    UBRR = baudrate; /* set the baud rate */
    UCR = BIT(RXEN) | BIT(TXEN); /* enable UART receiver and transmitter */
    }

/* Read and write functions */
unsigned char ReceiveByte( void )
    {
    while ( !(USR & (1<<RXC)) ) /* wait for incomming data */
        ; /* return the data */
    return UDR;
    }

void TransmitByte( unsigned char data )
    {
    while ( !(USR & (1<<UDRE)) )
        ; /* wait for empty transmit buffer */
    UDR = data; /* start transmittion */
    }

#ifdef TEST

/* main - a simple test program*/
void main( void )
    {
    InitUART( 11 ); /* set the baudrate to 19,200 bps using a
                    3.6864MHz crystal */
    while ( 1 ) /* forever */
        {
        TransmitByte( ReceiveByte() ); /* echo the received character */
        }
    }
#endif