main._c

一个关于AVR单片机的例程

//ICC-AVR application builder : 2007-5-30 15:23:23
// Target : M16
// Crystal: 7.3728Mhz

#include <iom16v.h>
#include <macros.h>

volatile unsigned char tmp=0;

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

//UART0 initialize
// 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 = BIT(URSEL) | 0x06;
 UBRRL = 0x2F; //set baud rate lo
 UBRRH = 0x00; //set baud rate hi
 UCSRB = (1<<RXCIE)|(1<<TXCIE)|(1<<RXEN)|(1<<TXEN);
}

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

/*
#pragma interrupt_handler uart0_udre_isr:13
void uart0_udre_isr(void)
{
 //character transferred to shift register so UDR is now empty
 UDR='x'; //是空就让，传输完成接着就会进入本中断。
}
*/

#pragma interrupt_handler uart0_tx_isr:14
void uart0_tx_isr(void)
{
 //character has been transmitted
 UDR=tmp;
}

//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)
{
 init_devices();  //主程序里面只初始化
 UDR=tmp;
 while(1)
 ;
}