#ifndef _delay_H__
#define _delay_H__

//晶振大小，保證延時的準確性
#define xtal 8
//#define xtal 4
//1us
extern void delay_1us(void);
//1ms
extern void delay_1ms(void);
//1s
extern void delay_1s(void);
//nus
extern void delay_us(unsigned int n);
//nms
extern void delay_ms(unsigned int n);
//ns
extern void delay_s(unsigned int n);

#endif