delay.c

hd7279接口芯片适用于扩展键盘和led

#include<intrins.h>
void long_delay(void)
{
	#pragma asm
	LONGDELAY:	MOV R5,#125//延时约250us
				DJNZ R5,$
	#pragma endasm
}
void short_delay(void)
{
	#pragma asm
	SHORTDELAY:	MOV R6,#50 //延时约100us
				DJNZ R6,$
	#pragma endasm
}
void delay1ms(unsigned int ms)
{
	unsigned char i,j;
	for(i=0;i<ms;i++)
		for(j=0;j<200;j++) //执行时间约1ms
		{
			_nop_();
			_nop_();
		}
}