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comparison delay.c @ 14:891841f5f785

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Fix delay() to be accurate as measured on the cro.
author Daniel O'Connor <darius@dons.net.au>
date Wed, 14 Nov 2012 12:24:21 +1030
parents 58d76cf522ff
children a38003b97de6
comparison
equal deleted inserted replaced
13:96c345d304af 14:891841f5f785
1 #include <stdint.h> 1 #include <stdint.h>
2 #include "stm32f10x.h" 2 #include "stm32f10x.h"
3 #include "delay.h" 3 #include "delay.h"
4 4
5 /* This is a bit rough and ready */ 5 /* Sleep for nCount usec
6 * TDS1012 on 2.5usec/div shows...
7 * 30usec = 29.60usec
8 * 60usec = 59.20usec
9 *
10 * XXX: not sure disable IRQ stuff is working as I see occasional (small) extra delays
11 */
6 void 12 void
7 delay(__IO uint32_t nCount) { 13 delay(uint32_t nCount) {
8 __IO uint32_t i; 14 __disable_irq();
9 15 for(; nCount != 0; nCount--) {
10 for(; nCount != 0; nCount--) 16 #ifdef SYSCLK_FREQ_72MHz
11 for (i = 0; i < 3900; i++) 17 __asm__("nop");
12 ; 18 __asm__("nop");
19 __asm__("nop");
20 __asm__("nop");
21 __asm__("nop");
22 __asm__("nop");
23 __asm__("nop");
24 __asm__("nop");
25
26 __asm__("nop");
27 __asm__("nop");
28 __asm__("nop");
29 __asm__("nop");
30 __asm__("nop");
31 __asm__("nop");
32 __asm__("nop");
33 __asm__("nop");
34
35 __asm__("nop");
36 __asm__("nop");
37 __asm__("nop");
38 __asm__("nop");
39 __asm__("nop");
40 __asm__("nop");
41 __asm__("nop");
42 __asm__("nop");
43
44 __asm__("nop");
45 __asm__("nop");
46 __asm__("nop");
47 __asm__("nop");
48 __asm__("nop");
49 __asm__("nop");
50 __asm__("nop");
51
52 __asm__("nop");
53 __asm__("nop");
54 __asm__("nop");
55 __asm__("nop");
56 __asm__("nop");
57 __asm__("nop");
58 __asm__("nop");
59 __asm__("nop");
60
61 __asm__("nop");
62 __asm__("nop");
63 __asm__("nop");
64 __asm__("nop");
65 __asm__("nop");
66 __asm__("nop");
67 __asm__("nop");
68
69 __asm__("nop");
70 __asm__("nop");
71 __asm__("nop");
72 __asm__("nop");
73 __asm__("nop");
74 __asm__("nop");
75 __asm__("nop");
76 __asm__("nop");
77 #else
78 #error Unknown clock frequency
79 #endif
80 }
81 __enable_irq();
13 } 82 }
14 83