AVR????????????

AVR????????????

1.?????????

???1ms;

void delay_1ms(void)

{

unsigned int i;

for(i=1;i<(unsigned int)(xtal*143-2);i++)

;

}

??????§µ?xtal???????????¦Ë?MHz. AVR ???????

??????????8M??????????????????????1000.25μs.??????????4M?????????????????????999.5μs. AVR ???????

??????????1ms????????????????¦Ï???????????????????????????????????????????????§Ý???????????§Ø??????§Ø???????????????????

??????????????1ms????????????????

void delay(unsigned int n)

{

unsigned int i;

for(i=0;i

delay_1ms();

}

??????????????????????????¦Ï?????????????????????????????????????. AVR ???????

2.??????

????4M??????ICCAVR??§à?mega16

//?????????131.072ms

void delay(unsigned int i) //??????T=2*(i+1)us????1=

{

while(--i);

}

????????8MHz?1μs????????? AVR ???????

void delay_1us(void)

{

asm("nop");

}

??????????¨²????????1μs?????

#define delay_1us(); asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop")

???§³??1μs????????????¨²?????????????????????????????

asm("nop");

???????????

?????????????????????????????????????? AVR ???????

void delay_us(unsigned int n)

{

unsigned int i;

for(i=0;i

delay_1us();

}

????????????????????????????§Ø?????????????????????????????????????.

???????????????????????????????§Ô??????????AVR ???????,???MCU??????????????(??????)??????????????????(?????§Ø???)????§Ù??????????????????????????????????????????????????§µ???????(?????????????????????????????????????????????????)???????????¡Â???????????????????????????§Ø???????????

???????????????????????????????

????admin  ?????????2018-05-19