trunk/Embedded/delay.h

/*
 *      Delay functions for HI-TECH C on the PIC18
 *
 *      Functions available:
 *              DelayUs(x)      Delay specified number of microseconds
 *              DelayMs(x)      Delay specified number of milliseconds
 *
 *      Note that there are range limits: 
 *      - on small values of x (i.e. x<10), the delay becomes less
 *      accurate. DelayUs is accurate with xtal frequencies in the
 *      range of 4-16MHZ, where x must not exceed 255. 
 *      For xtal frequencies > 16MHz the valid range for DelayUs
 *      is even smaller - hence affecting DelayMs.
 *      To use DelayUs it is only necessary to include this file.
 *      To use DelayMs you must include delay.c in your project.
 *
 *      Set the crystal frequency in the CPP predefined symbols list in
 *      HPDPIC, or on the PICC commmand line, e.g.
 *      picc -DXTAL_FREQ=4MHZ
 *
 *      or
 *      picc -DXTAL_FREQ=100KHZ
 *      
 *      Note that this is the crystal frequency, the CPU clock is
 *      divided by 4.
 *
 *      MAKE SURE this code is compiled with full optimization!!!
*/

#define MHZ     *1

#ifndef XTAL_FREQ
#define XTAL_FREQ       4MHZ            /* Crystal frequency in MHz */
#endif

#if     XTAL_FREQ < 8MHZ
#define uS_CNT  238                     /* 4x to make 1 mSec */
#endif
#if     XTAL_FREQ == 8MHZ
#ifndef uS_CNT
#define uS_CNT  244
#else
#define uS_CNT  246
#endif
#endif

#define FREQ_MULT       (XTAL_FREQ)/(4MHZ)

#define DelayUs(x)      { unsigned char _dcnt; \
                          if(x>=4) _dcnt=(x*(FREQ_MULT)/2); \
                          else _dcnt=1; \
                          while(--_dcnt > 0) \
                                {\
                                asm("nop");\
                                asm("nop");\
                                continue; }\
                } 

extern void DelayMs(unsigned char);


1	hedin	82	/*
2			* Delay functions for HI-TECH C on the PIC18
3			*
4			* Functions available:
5			* DelayUs(x) Delay specified number of microseconds
6			* DelayMs(x) Delay specified number of milliseconds
7			*
8			* Note that there are range limits:
9			* - on small values of x (i.e. x<10), the delay becomes less
10			* accurate. DelayUs is accurate with xtal frequencies in the
11			* range of 4-16MHZ, where x must not exceed 255.
12			* For xtal frequencies > 16MHz the valid range for DelayUs
13			* is even smaller - hence affecting DelayMs.
14			* To use DelayUs it is only necessary to include this file.
15			* To use DelayMs you must include delay.c in your project.
16			*
17			* Set the crystal frequency in the CPP predefined symbols list in
18			* HPDPIC, or on the PICC commmand line, e.g.
19			* picc -DXTAL_FREQ=4MHZ
20			*
21			* or
22			* picc -DXTAL_FREQ=100KHZ
23			*
24			* Note that this is the crystal frequency, the CPU clock is
25			* divided by 4.
26			*
27			* MAKE SURE this code is compiled with full optimization!!!
28			*/
29
30			#define MHZ *1
31
32			#ifndef XTAL_FREQ
33			#define XTAL_FREQ 4MHZ /* Crystal frequency in MHz */
34			#endif
35
36			#if XTAL_FREQ < 8MHZ
37			#define uS_CNT 238 /* 4x to make 1 mSec */
38			#endif
39			#if XTAL_FREQ == 8MHZ
40			#ifndef uS_CNT
41			#define uS_CNT 244
42			#else
43			#define uS_CNT 246
44			#endif
45			#endif
46
47			#define FREQ_MULT (XTAL_FREQ)/(4MHZ)
48
49			#define DelayUs(x) { unsigned char _dcnt; \
50			if(x>=4) _dcnt=(x*(FREQ_MULT)/2); \
51			else _dcnt=1; \
52			while(--_dcnt > 0) \
53			{\
54			asm("nop");\
55			asm("nop");\
56			continue; }\
57			}
58
59			extern void DelayMs(unsigned char);
60
61