1 /**
2 * \file
3 *
4 * \brief ARM functions for busy-wait delay loops
5 *
6 * Copyright (c) 2014-2015 Atmel Corporation. All rights reserved.
7 *
8 * \asf_license_start
9 *
10 * \page License
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions are met:
14 *
15 * 1. Redistributions of source code must retain the above copyright notice,
16 * this list of conditions and the following disclaimer.
17 *
18 * 2. Redistributions in binary form must reproduce the above copyright notice,
19 * this list of conditions and the following disclaimer in the documentation
20 * and/or other materials provided with the distribution.
21 *
22 * 3. The name of Atmel may not be used to endorse or promote products derived
23 * from this software without specific prior written permission.
24 *
25 * 4. This software may only be redistributed and used in connection with an
26 * Atmel microcontroller product.
27 *
28 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
29 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
30 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
31 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
32 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
36 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 *
40 * \asf_license_stop
41 *
42 */
43 /*
44 * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
45 */
46 #ifndef CYCLE_COUNTER_H_INCLUDED
47 #define CYCLE_COUNTER_H_INCLUDED
48
49 #include <compiler.h>
50 #include <clock.h>
51
52 #ifdef __cplusplus
53 extern "C" {
54 #endif
55
56 /**
57 * \name Convenience functions for busy-wait delay loops
58 *
59 * @{
60 */
61
62 /**
63 * \brief Delay loop to delay n number of cycles
64 * Delay program execution for at least the specified number of CPU cycles.
65 *
66 * \param n Number of cycles to delay
67 */
delay_cycles(const uint32_t n)68 static inline void delay_cycles(
69 const uint32_t n)
70 {
71 if (n > 0) {
72 SysTick->LOAD = n;
73 SysTick->VAL = 0;
74
75 while (!(SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk)) {
76 };
77 }
78 }
79
80 void delay_cycles_us(uint32_t n);
81
82 void delay_cycles_ms(uint32_t n);
83
84 /**
85 * \brief Delay program execution for at least the specified number of microseconds.
86 *
87 * \param delay number of microseconds to wait
88 */
89 #define cpu_delay_us(delay) delay_cycles_us(delay)
90
91 /**
92 * \brief Delay program execution for at least the specified number of milliseconds.
93 *
94 * \param delay number of milliseconds to wait
95 */
96 #define cpu_delay_ms(delay) delay_cycles_ms(delay)
97
98 /**
99 * \brief Delay program execution for at least the specified number of seconds.
100 *
101 * \param delay number of seconds to wait
102 */
103 #define cpu_delay_s(delay) delay_cycles_ms(1000 * delay)
104
105 /**
106 * @}
107 */
108
109 #ifdef __cplusplus
110 }
111 #endif
112
113 #endif /* CYCLE_COUNTER_H_INCLUDED */
114