Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

drivers/PwmOut.h@1:3deb71413561, 2017-07-20 (annotated)

Committer:
xuaner
Date:
Thu Jul 20 14:26:57 2017 +0000
Revision:
1:3deb71413561
Parent:
0:f269e3021894 
mbed_os

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elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 */
elessair 0:f269e3021894 16 #ifndef MBED_PWMOUT_H
elessair 0:f269e3021894 17 #define MBED_PWMOUT_H
elessair 0:f269e3021894 18
elessair 0:f269e3021894 19 #include "platform/platform.h"
elessair 0:f269e3021894 20
elessair 0:f269e3021894 21 #if DEVICE_PWMOUT
elessair 0:f269e3021894 22 #include "hal/pwmout_api.h"
elessair 0:f269e3021894 23 #include "platform/critical.h"
elessair 0:f269e3021894 24
elessair 0:f269e3021894 25 namespace mbed {
elessair 0:f269e3021894 26 /** \addtogroup drivers */
elessair 0:f269e3021894 27 /** @{*/
elessair 0:f269e3021894 28
elessair 0:f269e3021894 29 /** A pulse-width modulation digital output
elessair 0:f269e3021894 30 *
elessair 0:f269e3021894 31 * @Note Synchronization level: Interrupt safe
elessair 0:f269e3021894 32 *
elessair 0:f269e3021894 33 * Example
elessair 0:f269e3021894 34 * @code
elessair 0:f269e3021894 35 * // Fade a led on.
elessair 0:f269e3021894 36 * #include "mbed.h"
elessair 0:f269e3021894 37 *
elessair 0:f269e3021894 38 * PwmOut led(LED1);
elessair 0:f269e3021894 39 *
elessair 0:f269e3021894 40 * int main() {
elessair 0:f269e3021894 41 * while(1) {
elessair 0:f269e3021894 42 * led = led + 0.01;
elessair 0:f269e3021894 43 * wait(0.2);
elessair 0:f269e3021894 44 * if(led == 1.0) {
elessair 0:f269e3021894 45 * led = 0;
elessair 0:f269e3021894 46 * }
elessair 0:f269e3021894 47 * }
elessair 0:f269e3021894 48 * }
elessair 0:f269e3021894 49 * @endcode
elessair 0:f269e3021894 50 *
elessair 0:f269e3021894 51 * @note
elessair 0:f269e3021894 52 * On the LPC1768 and LPC2368, the PWMs all share the same
elessair 0:f269e3021894 53 * period - if you change the period for one, you change it for all.
elessair 0:f269e3021894 54 * Although routines that change the period maintain the duty cycle
elessair 0:f269e3021894 55 * for its PWM, all other PWMs will require their duty cycle to be
elessair 0:f269e3021894 56 * refreshed.
elessair 0:f269e3021894 57 */
elessair 0:f269e3021894 58 class PwmOut {
elessair 0:f269e3021894 59
elessair 0:f269e3021894 60 public:
elessair 0:f269e3021894 61
elessair 0:f269e3021894 62 /** Create a PwmOut connected to the specified pin
elessair 0:f269e3021894 63 *
elessair 0:f269e3021894 64 * @param pin PwmOut pin to connect to
elessair 0:f269e3021894 65 */
elessair 0:f269e3021894 66 PwmOut(PinName pin) {
elessair 0:f269e3021894 67 core_util_critical_section_enter();
elessair 0:f269e3021894 68 pwmout_init(&_pwm, pin);
elessair 0:f269e3021894 69 core_util_critical_section_exit();
elessair 0:f269e3021894 70 }
elessair 0:f269e3021894 71
elessair 0:f269e3021894 72 /** Set the ouput duty-cycle, specified as a percentage (float)
elessair 0:f269e3021894 73 *
elessair 0:f269e3021894 74 * @param value A floating-point value representing the output duty-cycle,
elessair 0:f269e3021894 75 * specified as a percentage. The value should lie between
elessair 0:f269e3021894 76 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
elessair 0:f269e3021894 77 * Values outside this range will be saturated to 0.0f or 1.0f.
elessair 0:f269e3021894 78 */
elessair 0:f269e3021894 79 void write(float value) {
elessair 0:f269e3021894 80 core_util_critical_section_enter();
elessair 0:f269e3021894 81 pwmout_write(&_pwm, value);
elessair 0:f269e3021894 82 core_util_critical_section_exit();
elessair 0:f269e3021894 83 }
elessair 0:f269e3021894 84
elessair 0:f269e3021894 85 /** Return the current output duty-cycle setting, measured as a percentage (float)
elessair 0:f269e3021894 86 *
elessair 0:f269e3021894 87 * @returns
elessair 0:f269e3021894 88 * A floating-point value representing the current duty-cycle being output on the pin,
elessair 0:f269e3021894 89 * measured as a percentage. The returned value will lie between
elessair 0:f269e3021894 90 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
elessair 0:f269e3021894 91 *
elessair 0:f269e3021894 92 * @note
elessair 0:f269e3021894 93 * This value may not match exactly the value set by a previous <write>.
elessair 0:f269e3021894 94 */
elessair 0:f269e3021894 95 float read() {
elessair 0:f269e3021894 96 core_util_critical_section_enter();
elessair 0:f269e3021894 97 float val = pwmout_read(&_pwm);
elessair 0:f269e3021894 98 core_util_critical_section_exit();
elessair 0:f269e3021894 99 return val;
elessair 0:f269e3021894 100 }
elessair 0:f269e3021894 101
elessair 0:f269e3021894 102 /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
elessair 0:f269e3021894 103 *
elessair 0:f269e3021894 104 * @note
elessair 0:f269e3021894 105 * The resolution is currently in microseconds; periods smaller than this
elessair 0:f269e3021894 106 * will be set to zero.
elessair 0:f269e3021894 107 */
elessair 0:f269e3021894 108 void period(float seconds) {
elessair 0:f269e3021894 109 core_util_critical_section_enter();
elessair 0:f269e3021894 110 pwmout_period(&_pwm, seconds);
elessair 0:f269e3021894 111 core_util_critical_section_exit();
elessair 0:f269e3021894 112 }
elessair 0:f269e3021894 113
elessair 0:f269e3021894 114 /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
elessair 0:f269e3021894 115 */
elessair 0:f269e3021894 116 void period_ms(int ms) {
elessair 0:f269e3021894 117 core_util_critical_section_enter();
elessair 0:f269e3021894 118 pwmout_period_ms(&_pwm, ms);
elessair 0:f269e3021894 119 core_util_critical_section_exit();
elessair 0:f269e3021894 120 }
elessair 0:f269e3021894 121
elessair 0:f269e3021894 122 /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
elessair 0:f269e3021894 123 */
elessair 0:f269e3021894 124 void period_us(int us) {
elessair 0:f269e3021894 125 core_util_critical_section_enter();
elessair 0:f269e3021894 126 pwmout_period_us(&_pwm, us);
elessair 0:f269e3021894 127 core_util_critical_section_exit();
elessair 0:f269e3021894 128 }
elessair 0:f269e3021894 129
elessair 0:f269e3021894 130 /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
elessair 0:f269e3021894 131 */
elessair 0:f269e3021894 132 void pulsewidth(float seconds) {
elessair 0:f269e3021894 133 core_util_critical_section_enter();
elessair 0:f269e3021894 134 pwmout_pulsewidth(&_pwm, seconds);
elessair 0:f269e3021894 135 core_util_critical_section_exit();
elessair 0:f269e3021894 136 }
elessair 0:f269e3021894 137
elessair 0:f269e3021894 138 /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
elessair 0:f269e3021894 139 */
elessair 0:f269e3021894 140 void pulsewidth_ms(int ms) {
elessair 0:f269e3021894 141 core_util_critical_section_enter();
elessair 0:f269e3021894 142 pwmout_pulsewidth_ms(&_pwm, ms);
elessair 0:f269e3021894 143 core_util_critical_section_exit();
elessair 0:f269e3021894 144 }
elessair 0:f269e3021894 145
elessair 0:f269e3021894 146 /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
elessair 0:f269e3021894 147 */
elessair 0:f269e3021894 148 void pulsewidth_us(int us) {
elessair 0:f269e3021894 149 core_util_critical_section_enter();
elessair 0:f269e3021894 150 pwmout_pulsewidth_us(&_pwm, us);
elessair 0:f269e3021894 151 core_util_critical_section_exit();
elessair 0:f269e3021894 152 }
elessair 0:f269e3021894 153
elessair 0:f269e3021894 154 /** A operator shorthand for write()
elessair 0:f269e3021894 155 */
elessair 0:f269e3021894 156 PwmOut& operator= (float value) {
elessair 0:f269e3021894 157 // Underlying call is thread safe
elessair 0:f269e3021894 158 write(value);
elessair 0:f269e3021894 159 return *this;
elessair 0:f269e3021894 160 }
elessair 0:f269e3021894 161
elessair 0:f269e3021894 162 PwmOut& operator= (PwmOut& rhs) {
elessair 0:f269e3021894 163 // Underlying call is thread safe
elessair 0:f269e3021894 164 write(rhs.read());
elessair 0:f269e3021894 165 return *this;
elessair 0:f269e3021894 166 }
elessair 0:f269e3021894 167
elessair 0:f269e3021894 168 /** An operator shorthand for read()
elessair 0:f269e3021894 169 */
elessair 0:f269e3021894 170 operator float() {
elessair 0:f269e3021894 171 // Underlying call is thread safe
elessair 0:f269e3021894 172 return read();
elessair 0:f269e3021894 173 }
elessair 0:f269e3021894 174
elessair 0:f269e3021894 175 protected:
elessair 0:f269e3021894 176 pwmout_t _pwm;
elessair 0:f269e3021894 177 };
elessair 0:f269e3021894 178
elessair 0:f269e3021894 179 } // namespace mbed
elessair 0:f269e3021894 180
elessair 0:f269e3021894 181 #endif
elessair 0:f269e3021894 182
elessair 0:f269e3021894 183 #endif
elessair 0:f269e3021894 184
elessair 0:f269e3021894 185 /** @}*/