nrf_delay.h

00001 /*
00002  * Copyright (c) Nordic Semiconductor ASA
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without modification,
00006  * are permitted provided that the following conditions are met:
00007  *
00008  *   1. Redistributions of source code must retain the above copyright notice, this
00009  *   list of conditions and the following disclaimer.
00010  *
00011  *   2. Redistributions in binary form must reproduce the above copyright notice, this
00012  *   list of conditions and the following disclaimer in the documentation and/or
00013  *   other materials provided with the distribution.
00014  *
00015  *   3. Neither the name of Nordic Semiconductor ASA nor the names of other
00016  *   contributors to this software may be used to endorse or promote products
00017  *   derived from this software without specific prior written permission.
00018  *
00019  *
00020  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
00021  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
00022  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00023  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
00024  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
00025  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00026  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
00027  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00028  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00029  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030  *
00031  */
00032 
00033 #ifndef _NRF_DELAY_H
00034 #define _NRF_DELAY_H
00035 
00036 #include "nrf.h"
00037 
00038 /**
00039  * @brief Function for delaying execution for number of microseconds.
00040  *
00041  * @note NRF52 has instruction cache and because of that delay is not precise.
00042  *
00043  * @param number_of_ms
00044  */
00045 /*lint --e{438, 522} "Variable not used" "Function lacks side-effects" */
00046 #if defined ( __CC_ARM   )
00047 
00048 static __ASM void __INLINE nrf_delay_us(uint32_t volatile number_of_us)
00049 {
00050 loop
00051         SUBS    R0, R0, #1
00052         NOP
00053         NOP
00054         NOP
00055         NOP
00056         NOP
00057         NOP
00058         NOP
00059         NOP
00060         NOP
00061         NOP
00062         NOP
00063         NOP
00064 #ifdef NRF52
00065         NOP
00066         NOP
00067         NOP
00068         NOP
00069         NOP
00070         NOP
00071         NOP
00072         NOP
00073         NOP
00074         NOP
00075         NOP
00076         NOP
00077         NOP
00078         NOP
00079         NOP
00080         NOP
00081         NOP
00082         NOP
00083         NOP
00084         NOP
00085         NOP
00086         NOP
00087         NOP
00088         NOP
00089         NOP
00090         NOP
00091         NOP
00092         NOP
00093         NOP
00094         NOP
00095         NOP
00096         NOP
00097         NOP
00098         NOP
00099         NOP
00100         NOP
00101         NOP
00102         NOP
00103         NOP
00104         NOP
00105         NOP
00106         NOP
00107         NOP
00108         NOP
00109 #endif
00110         BNE    loop
00111         BX     LR
00112 }
00113 
00114 #elif defined ( __ICCARM__ )
00115 
00116 static void __INLINE nrf_delay_us(uint32_t volatile number_of_us)
00117 {
00118 __ASM (
00119 "loop:\n\t"
00120        " SUBS R0, R0, #1\n\t"
00121        " NOP\n\t"
00122        " NOP\n\t"
00123        " NOP\n\t"
00124        " NOP\n\t"
00125        " NOP\n\t"
00126        " NOP\n\t"
00127        " NOP\n\t"
00128        " NOP\n\t"
00129        " NOP\n\t"
00130        " NOP\n\t"
00131        " NOP\n\t"
00132        " NOP\n\t"
00133 #ifdef NRF52
00134         " NOP\n\t"
00135         " NOP\n\t"
00136         " NOP\n\t"
00137         " NOP\n\t"
00138         " NOP\n\t"
00139         " NOP\n\t"
00140         " NOP\n\t"
00141         " NOP\n\t"
00142         " NOP\n\t"
00143         " NOP\n\t"
00144         " NOP\n\t"
00145         " NOP\n\t"
00146         " NOP\n\t"
00147         " NOP\n\t"
00148         " NOP\n\t"
00149         " NOP\n\t"
00150         " NOP\n\t"
00151         " NOP\n\t"
00152         " NOP\n\t"
00153         " NOP\n\t"
00154         " NOP\n\t"
00155         " NOP\n\t"
00156         " NOP\n\t"
00157         " NOP\n\t"
00158         " NOP\n\t"
00159         " NOP\n\t"
00160         " NOP\n\t"
00161         " NOP\n\t"
00162         " NOP\n\t"
00163         " NOP\n\t"
00164         " NOP\n\t"
00165         " NOP\n\t"
00166         " NOP\n\t"
00167         " NOP\n\t"
00168         " NOP\n\t"
00169         " NOP\n\t"
00170         " NOP\n\t"
00171         " NOP\n\t"
00172         " NOP\n\t"
00173         " NOP\n\t"
00174         " NOP\n\t"
00175         " NOP\n\t"
00176         " NOP\n\t"
00177         " NOP\n\t"
00178         " NOP\n\t"
00179 #endif
00180        " BNE.n loop\n\t");
00181 }
00182 
00183 #elif defined ( _WIN32 ) || defined ( __unix ) || defined( __APPLE__ )
00184 
00185 __STATIC_INLINE void nrf_delay_us(uint32_t volatile number_of_us);
00186 
00187 #ifndef CUSTOM_NRF_DELAY_US
00188 __STATIC_INLINE void nrf_delay_us(uint32_t volatile number_of_us)
00189 {}
00190 #endif
00191 
00192 #elif defined ( __GNUC__ )
00193 
00194 static void __INLINE nrf_delay_us(uint32_t volatile number_of_us) __attribute__((always_inline));
00195 static void __INLINE nrf_delay_us(uint32_t volatile number_of_us)
00196 {
00197 register uint32_t delay __ASM ("r0") = number_of_us;
00198 __ASM volatile (
00199 #ifdef NRF51
00200         ".syntax unified\n"
00201 #endif
00202     "1:\n"
00203     " SUBS %0, %0, #1\n"
00204     " NOP\n"
00205     " NOP\n"
00206     " NOP\n"
00207     " NOP\n"
00208     " NOP\n"
00209     " NOP\n"   
00210     " NOP\n"  
00211     " NOP\n"
00212     " NOP\n"
00213     " NOP\n"
00214     " NOP\n"
00215     " NOP\n"
00216 #ifdef NRF52
00217     " NOP\n"
00218     " NOP\n"
00219     " NOP\n"
00220     " NOP\n"
00221     " NOP\n"
00222     " NOP\n"
00223     " NOP\n"
00224     " NOP\n"
00225     " NOP\n"
00226     " NOP\n"
00227     " NOP\n"
00228     " NOP\n"
00229     " NOP\n"
00230     " NOP\n"
00231     " NOP\n"
00232     " NOP\n"
00233     " NOP\n"
00234     " NOP\n"
00235     " NOP\n"
00236     " NOP\n"
00237     " NOP\n"
00238     " NOP\n"
00239     " NOP\n"
00240     " NOP\n"
00241     " NOP\n"
00242     " NOP\n"
00243     " NOP\n"
00244     " NOP\n"
00245     " NOP\n"
00246     " NOP\n"
00247     " NOP\n"
00248     " NOP\n"
00249     " NOP\n"
00250     " NOP\n"
00251     " NOP\n"
00252     " NOP\n"
00253     " NOP\n"
00254     " NOP\n"
00255     " NOP\n"
00256     " NOP\n"
00257     " NOP\n"
00258     " NOP\n"
00259     " NOP\n"
00260     " NOP\n"
00261     " NOP\n"
00262     " NOP\n"
00263 #endif
00264     " BNE 1b\n"
00265 #ifdef NRF51
00266     ".syntax divided\n"
00267 #endif
00268     : "+r" (delay));
00269 }
00270 #endif
00271 
00272 void nrf_delay_ms(uint32_t volatile number_of_ms);
00273 
00274 #endif