uart.c

这是关于AVR单片机学习的初步开发

//Designed by BUAA Alf
//串口通讯演示程序；
//实现了串口收发数据，先从PC上发一8位二进制数据，单片机会返回自己收到的数据。


//ICC-AVR application builder : 2005-3-8 下午 09:54:40
// Target : M8
// Crystal: 11.059Mhz

#include <iom8v.h>
#include <macros.h>

void port_init(void)
{
 PORTB = 0xFF;
 DDRB  = 0x00;
 PORTC = 0x7F; //m103 output only
 DDRC  = 0x00;
 PORTD = 0xFF;
 DDRD  = 0x00;
}

//UART0 initialisation
// desired baud rate: 9600
// actual: baud rate:9600 (0.0%)
// char size: 8 bit
// parity: Disabled
void uart0_init(void)
{
 UCSRB = 0x00; //disable while setting baud rate
 UCSRA = 0x00;
 UCSRC = 0x86;
 UBRRL = 0x47; //set baud rate lo
 UBRRH = 0x00; //set baud rate hi
 UCSRB = 0x98;
}

#pragma interrupt_handler uart0_rx_isr:12
void uart0_rx_isr(void)
{
 //uart has received a character in UDR
 char temp;
 temp = UDR;
 UDR = temp;
}

//call this routine to initialise 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 initialised
}

//
void main(void)
{
 init_devices();
 //insert your functional code here...
 while(1);
}