soft_test.c

一个关于AVR单片机的例程

// Test Soft-Uart : See Atmel Applicaton Note 305
// File: soft_test.c
// Target : mega16
// Crystal: 7.3728 Mhz
// Date 05/30/2007
// for Imagecraft ICCAVR Ver. 6.31
// Usage : if you need more then one UART
// Customer settings : SEE soft_uart.s
// 程序被移植到mega16上
// 古欣 AVR与虚拟仪器 www.avrvi.com
// 连接：电源跳线5V，晶振跳线7.3728M，串口使用跳线JP4的1和2短接
// 程序原型Written/adapted by Dipl.Ing.J.Zastrow


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

//function prototypes for soft_uart.s
//one byte return value in R16 !!!
extern unsigned char getit(void);
//one byte argument in R16 !!!
extern putit(register unsigned char key);
//initialise TxD,RxD port pins
extern void init_soft_uart(void);


void port_init(void)
{
 //default settings all inputs and pull up 
 PORTA = 0xFF;
 DDRA  = 0x00;
 PORTB = 0xFF;
 DDRB  = 0xFF;
 PORTC = 0xFF;
 DDRC  = 0x00;
 PORTD = 0xFF;
 DDRD  = 0x00;
}

//call this routine to initialise all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 port_init();
 MCUCR = 0x00;
 TIMSK = 0x00;
 SEI(); //re-enable interrupts
 //all peripherals are now initialised
}

//Simply connect RS232 SPARE to
//PD0 to receive and PD1 to transmitt
 
void main(void)
{
 unsigned char s=0,i=0;
 unsigned char buf[]="www.avrvi.com\r\n";
 //defaul
 init_devices();
 
 //do custom settings in soft_uart.s !!!
 init_soft_uart();
 for(i=0;i<16;i++)
 {
  putit(buf[i]);
 }
 while(1){
 putit('T'); //T
 putit('E'); //E
 putit('S'); //S
 putit('T'); //T
 putit(':'); //:
 s = getit();//输入一个数
 putit(s);   //输出一个数
 putit(0x0D);//HU
 putit(0x0A);//LF
 }//end while
 
}//end main