Simon Cooksey / mbed-os

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drivers/PwmOut.h@0:fb7af294d5d9, 2016-11-17 (annotated)

Committer:
Simon Cooksey
Date:
Thu Nov 17 16:43:53 2016 +0000
Revision:
0:fb7af294d5d9
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Simon Cooksey 0:fb7af294d5d9 1 /* mbed Microcontroller Library
Simon Cooksey 0:fb7af294d5d9 2 * Copyright (c) 2006-2013 ARM Limited
Simon Cooksey 0:fb7af294d5d9 3 *
Simon Cooksey 0:fb7af294d5d9 4 * Licensed under the Apache License, Version 2.0 (the "License");
Simon Cooksey 0:fb7af294d5d9 5 * you may not use this file except in compliance with the License.
Simon Cooksey 0:fb7af294d5d9 6 * You may obtain a copy of the License at
Simon Cooksey 0:fb7af294d5d9 7 *
Simon Cooksey 0:fb7af294d5d9 8 * http://www.apache.org/licenses/LICENSE-2.0
Simon Cooksey 0:fb7af294d5d9 9 *
Simon Cooksey 0:fb7af294d5d9 10 * Unless required by applicable law or agreed to in writing, software
Simon Cooksey 0:fb7af294d5d9 11 * distributed under the License is distributed on an "AS IS" BASIS,
Simon Cooksey 0:fb7af294d5d9 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
Simon Cooksey 0:fb7af294d5d9 13 * See the License for the specific language governing permissions and
Simon Cooksey 0:fb7af294d5d9 14 * limitations under the License.
Simon Cooksey 0:fb7af294d5d9 15 */
Simon Cooksey 0:fb7af294d5d9 16 #ifndef MBED_PWMOUT_H
Simon Cooksey 0:fb7af294d5d9 17 #define MBED_PWMOUT_H
Simon Cooksey 0:fb7af294d5d9 18
Simon Cooksey 0:fb7af294d5d9 19 #include "platform/platform.h"
Simon Cooksey 0:fb7af294d5d9 20
Simon Cooksey 0:fb7af294d5d9 21 #if DEVICE_PWMOUT
Simon Cooksey 0:fb7af294d5d9 22 #include "hal/pwmout_api.h"
Simon Cooksey 0:fb7af294d5d9 23 #include "platform/critical.h"
Simon Cooksey 0:fb7af294d5d9 24
Simon Cooksey 0:fb7af294d5d9 25 namespace mbed {
Simon Cooksey 0:fb7af294d5d9 26 /** \addtogroup drivers */
Simon Cooksey 0:fb7af294d5d9 27 /** @{*/
Simon Cooksey 0:fb7af294d5d9 28
Simon Cooksey 0:fb7af294d5d9 29 /** A pulse-width modulation digital output
Simon Cooksey 0:fb7af294d5d9 30 *
Simon Cooksey 0:fb7af294d5d9 31 * @Note Synchronization level: Interrupt safe
Simon Cooksey 0:fb7af294d5d9 32 *
Simon Cooksey 0:fb7af294d5d9 33 * Example
Simon Cooksey 0:fb7af294d5d9 34 * @code
Simon Cooksey 0:fb7af294d5d9 35 * // Fade a led on.
Simon Cooksey 0:fb7af294d5d9 36 * #include "mbed.h"
Simon Cooksey 0:fb7af294d5d9 37 *
Simon Cooksey 0:fb7af294d5d9 38 * PwmOut led(LED1);
Simon Cooksey 0:fb7af294d5d9 39 *
Simon Cooksey 0:fb7af294d5d9 40 * int main() {
Simon Cooksey 0:fb7af294d5d9 41 * while(1) {
Simon Cooksey 0:fb7af294d5d9 42 * led = led + 0.01;
Simon Cooksey 0:fb7af294d5d9 43 * wait(0.2);
Simon Cooksey 0:fb7af294d5d9 44 * if(led == 1.0) {
Simon Cooksey 0:fb7af294d5d9 45 * led = 0;
Simon Cooksey 0:fb7af294d5d9 46 * }
Simon Cooksey 0:fb7af294d5d9 47 * }
Simon Cooksey 0:fb7af294d5d9 48 * }
Simon Cooksey 0:fb7af294d5d9 49 * @endcode
Simon Cooksey 0:fb7af294d5d9 50 *
Simon Cooksey 0:fb7af294d5d9 51 * @note
Simon Cooksey 0:fb7af294d5d9 52 * On the LPC1768 and LPC2368, the PWMs all share the same
Simon Cooksey 0:fb7af294d5d9 53 * period - if you change the period for one, you change it for all.
Simon Cooksey 0:fb7af294d5d9 54 * Although routines that change the period maintain the duty cycle
Simon Cooksey 0:fb7af294d5d9 55 * for its PWM, all other PWMs will require their duty cycle to be
Simon Cooksey 0:fb7af294d5d9 56 * refreshed.
Simon Cooksey 0:fb7af294d5d9 57 */
Simon Cooksey 0:fb7af294d5d9 58 class PwmOut {
Simon Cooksey 0:fb7af294d5d9 59
Simon Cooksey 0:fb7af294d5d9 60 public:
Simon Cooksey 0:fb7af294d5d9 61
Simon Cooksey 0:fb7af294d5d9 62 /** Create a PwmOut connected to the specified pin
Simon Cooksey 0:fb7af294d5d9 63 *
Simon Cooksey 0:fb7af294d5d9 64 * @param pin PwmOut pin to connect to
Simon Cooksey 0:fb7af294d5d9 65 */
Simon Cooksey 0:fb7af294d5d9 66 PwmOut(PinName pin) {
Simon Cooksey 0:fb7af294d5d9 67 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 68 pwmout_init(&_pwm, pin);
Simon Cooksey 0:fb7af294d5d9 69 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 70 }
Simon Cooksey 0:fb7af294d5d9 71
Simon Cooksey 0:fb7af294d5d9 72 /** Set the ouput duty-cycle, specified as a percentage (float)
Simon Cooksey 0:fb7af294d5d9 73 *
Simon Cooksey 0:fb7af294d5d9 74 * @param value A floating-point value representing the output duty-cycle,
Simon Cooksey 0:fb7af294d5d9 75 * specified as a percentage. The value should lie between
Simon Cooksey 0:fb7af294d5d9 76 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
Simon Cooksey 0:fb7af294d5d9 77 * Values outside this range will be saturated to 0.0f or 1.0f.
Simon Cooksey 0:fb7af294d5d9 78 */
Simon Cooksey 0:fb7af294d5d9 79 void write(float value) {
Simon Cooksey 0:fb7af294d5d9 80 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 81 pwmout_write(&_pwm, value);
Simon Cooksey 0:fb7af294d5d9 82 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 83 }
Simon Cooksey 0:fb7af294d5d9 84
Simon Cooksey 0:fb7af294d5d9 85 /** Return the current output duty-cycle setting, measured as a percentage (float)
Simon Cooksey 0:fb7af294d5d9 86 *
Simon Cooksey 0:fb7af294d5d9 87 * @returns
Simon Cooksey 0:fb7af294d5d9 88 * A floating-point value representing the current duty-cycle being output on the pin,
Simon Cooksey 0:fb7af294d5d9 89 * measured as a percentage. The returned value will lie between
Simon Cooksey 0:fb7af294d5d9 90 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
Simon Cooksey 0:fb7af294d5d9 91 *
Simon Cooksey 0:fb7af294d5d9 92 * @note
Simon Cooksey 0:fb7af294d5d9 93 * This value may not match exactly the value set by a previous <write>.
Simon Cooksey 0:fb7af294d5d9 94 */
Simon Cooksey 0:fb7af294d5d9 95 float read() {
Simon Cooksey 0:fb7af294d5d9 96 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 97 float val = pwmout_read(&_pwm);
Simon Cooksey 0:fb7af294d5d9 98 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 99 return val;
Simon Cooksey 0:fb7af294d5d9 100 }
Simon Cooksey 0:fb7af294d5d9 101
Simon Cooksey 0:fb7af294d5d9 102 /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
Simon Cooksey 0:fb7af294d5d9 103 *
Simon Cooksey 0:fb7af294d5d9 104 * @note
Simon Cooksey 0:fb7af294d5d9 105 * The resolution is currently in microseconds; periods smaller than this
Simon Cooksey 0:fb7af294d5d9 106 * will be set to zero.
Simon Cooksey 0:fb7af294d5d9 107 */
Simon Cooksey 0:fb7af294d5d9 108 void period(float seconds) {
Simon Cooksey 0:fb7af294d5d9 109 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 110 pwmout_period(&_pwm, seconds);
Simon Cooksey 0:fb7af294d5d9 111 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 112 }
Simon Cooksey 0:fb7af294d5d9 113
Simon Cooksey 0:fb7af294d5d9 114 /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
Simon Cooksey 0:fb7af294d5d9 115 */
Simon Cooksey 0:fb7af294d5d9 116 void period_ms(int ms) {
Simon Cooksey 0:fb7af294d5d9 117 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 118 pwmout_period_ms(&_pwm, ms);
Simon Cooksey 0:fb7af294d5d9 119 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 120 }
Simon Cooksey 0:fb7af294d5d9 121
Simon Cooksey 0:fb7af294d5d9 122 /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
Simon Cooksey 0:fb7af294d5d9 123 */
Simon Cooksey 0:fb7af294d5d9 124 void period_us(int us) {
Simon Cooksey 0:fb7af294d5d9 125 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 126 pwmout_period_us(&_pwm, us);
Simon Cooksey 0:fb7af294d5d9 127 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 128 }
Simon Cooksey 0:fb7af294d5d9 129
Simon Cooksey 0:fb7af294d5d9 130 /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
Simon Cooksey 0:fb7af294d5d9 131 */
Simon Cooksey 0:fb7af294d5d9 132 void pulsewidth(float seconds) {
Simon Cooksey 0:fb7af294d5d9 133 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 134 pwmout_pulsewidth(&_pwm, seconds);
Simon Cooksey 0:fb7af294d5d9 135 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 136 }
Simon Cooksey 0:fb7af294d5d9 137
Simon Cooksey 0:fb7af294d5d9 138 /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
Simon Cooksey 0:fb7af294d5d9 139 */
Simon Cooksey 0:fb7af294d5d9 140 void pulsewidth_ms(int ms) {
Simon Cooksey 0:fb7af294d5d9 141 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 142 pwmout_pulsewidth_ms(&_pwm, ms);
Simon Cooksey 0:fb7af294d5d9 143 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 144 }
Simon Cooksey 0:fb7af294d5d9 145
Simon Cooksey 0:fb7af294d5d9 146 /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
Simon Cooksey 0:fb7af294d5d9 147 */
Simon Cooksey 0:fb7af294d5d9 148 void pulsewidth_us(int us) {
Simon Cooksey 0:fb7af294d5d9 149 core_util_critical_section_enter();
Simon Cooksey 0:fb7af294d5d9 150 pwmout_pulsewidth_us(&_pwm, us);
Simon Cooksey 0:fb7af294d5d9 151 core_util_critical_section_exit();
Simon Cooksey 0:fb7af294d5d9 152 }
Simon Cooksey 0:fb7af294d5d9 153
Simon Cooksey 0:fb7af294d5d9 154 /** A operator shorthand for write()
Simon Cooksey 0:fb7af294d5d9 155 */
Simon Cooksey 0:fb7af294d5d9 156 PwmOut& operator= (float value) {
Simon Cooksey 0:fb7af294d5d9 157 // Underlying call is thread safe
Simon Cooksey 0:fb7af294d5d9 158 write(value);
Simon Cooksey 0:fb7af294d5d9 159 return *this;
Simon Cooksey 0:fb7af294d5d9 160 }
Simon Cooksey 0:fb7af294d5d9 161
Simon Cooksey 0:fb7af294d5d9 162 PwmOut& operator= (PwmOut& rhs) {
Simon Cooksey 0:fb7af294d5d9 163 // Underlying call is thread safe
Simon Cooksey 0:fb7af294d5d9 164 write(rhs.read());
Simon Cooksey 0:fb7af294d5d9 165 return *this;
Simon Cooksey 0:fb7af294d5d9 166 }
Simon Cooksey 0:fb7af294d5d9 167
Simon Cooksey 0:fb7af294d5d9 168 /** An operator shorthand for read()
Simon Cooksey 0:fb7af294d5d9 169 */
Simon Cooksey 0:fb7af294d5d9 170 operator float() {
Simon Cooksey 0:fb7af294d5d9 171 // Underlying call is thread safe
Simon Cooksey 0:fb7af294d5d9 172 return read();
Simon Cooksey 0:fb7af294d5d9 173 }
Simon Cooksey 0:fb7af294d5d9 174
Simon Cooksey 0:fb7af294d5d9 175 protected:
Simon Cooksey 0:fb7af294d5d9 176 pwmout_t _pwm;
Simon Cooksey 0:fb7af294d5d9 177 };
Simon Cooksey 0:fb7af294d5d9 178
Simon Cooksey 0:fb7af294d5d9 179 } // namespace mbed
Simon Cooksey 0:fb7af294d5d9 180
Simon Cooksey 0:fb7af294d5d9 181 #endif
Simon Cooksey 0:fb7af294d5d9 182
Simon Cooksey 0:fb7af294d5d9 183 #endif
Simon Cooksey 0:fb7af294d5d9 184
Simon Cooksey 0:fb7af294d5d9 185 /** @}*/