1 /**
2 * \file
3 *
4 * \brief ARM functions for busy-wait delay loops
5 *
6 * Copyright (c) 2012-2015 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
47 #include "delay.h"
48
49 /**
50 * \brief Initialize the delay driver.
51 *
52 * Not used in cycle mode.
53 */
delay_init(void)54 void delay_init(void)
55 {
56 }
57
58 // Delay loop is put to SRAM so that FWS will not affect delay time
59 OPTIMIZE_HIGH
60 RAMFUNC
portable_delay_cycles(unsigned long n)61 void portable_delay_cycles(unsigned long n)
62 {
63 UNUSED(n);
64
65 __asm (
66 "loop: DMB \n"
67 #ifdef __ICCARM__
68 "SUBS r0, r0, #1 \n"
69 #else
70 "SUB r0, r0, #1 \n"
71 #endif
72 "CMP r0, #0 \n"
73 "BNE loop "
74 );
75 }
76