Use T0 timer to write back and forth water lamp, but why only one lamp continues to light up?

evanleung

Use T0 timer to write back and forth water lamp, but why only one lamp continues to light up? [Copy link]

I used the T0 timer to write the water lamp back and forth, but only one lamp is on and the water does not flow. I don’t know what the problem is. Can you help me analyze it and see where I went wrong.

#include<reg52.h>
#include<intrins.h>
#define uint unsigned int
	uint x;
	char tmp;
void delayms();
void main()
{
	uint i;
	tmp=0x7f;
	P2=tmp;
	delayms();
	while(1)
	{
		for(i=0;i<7;i++)
		{
			tmp=_cror_(tmp,1);
			P2=tmp;
			delayms();
		}
		for(i=7;i>0;i--)
		{
			tmp=_crol_(tmp,1);
			P2=tmp;
			delayms();
		}
	}
}

void delayms()
{
	TMOD=0x01;
	TH0=(65536-45872)/256;
	TL0=(65536-45872)%256;
	EA=1;
	ET0=1;
	TR0=1;
	while(1);
}

void time() interrupt 1
{
	TH0=(65536-45872)/256;
	TL0=(65536-45872)%256;
	x++;
	if(x==20)
	{
		x=0;
	}
}

swustlx86

What else can be done by adding whie(1); in delayms()?

evanleung

swustlx86 published on 2020-4-11 12:14 Add whie(1); to delayms(), what else can you do

Add while(1) to delayms() to wait for interruption. Now the interruption doesn't seem to have any effect.

shadaodadi1

So what if the interruption is over? Your program is still looping endlessly in delayms(). . . . And the interrupt function does nothing. . .

• uint i;
• tmp=0x7f;
• P2=tmp;
• delayms();
• After executing 1 P2 output, it will enter the infinite loop of delayms. Anyway, you can judge the entire condition in while and jump out of the loop when the requirements are met.

呦，阿里阿朵

You are writing interrupts and delays together and using them together. While (1) cannot appear in an interrupt or delay, it means that your program is stuck. Instead of adding delayms and interrupts (in fact, your interrupts are not running, the following two functions are useless), just write a delay() function with a delay of 1S.

freebsder

You can't jump out without interruption, and of course it won't be executed later.