teralytic / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed by teralytic

api/PwmOut.h@148:4802eb17e82b, 2016-10-17 (annotated)

Committer:
rodriguise
Date:
Mon Oct 17 18:47:01 2016 +0000
Revision:
148:4802eb17e82b
Parent:
144:ef7eb2e8f9f7 
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<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #ifndef MBED_PWMOUT_H
<> 144:ef7eb2e8f9f7 17 #define MBED_PWMOUT_H
<> 144:ef7eb2e8f9f7 18
<> 144:ef7eb2e8f9f7 19 #include "platform.h"
<> 144:ef7eb2e8f9f7 20
<> 144:ef7eb2e8f9f7 21 #if DEVICE_PWMOUT
<> 144:ef7eb2e8f9f7 22 #include "pwmout_api.h"
<> 144:ef7eb2e8f9f7 23 #include "critical.h"
<> 144:ef7eb2e8f9f7 24
<> 144:ef7eb2e8f9f7 25 namespace mbed {
<> 144:ef7eb2e8f9f7 26
<> 144:ef7eb2e8f9f7 27 /** A pulse-width modulation digital output
<> 144:ef7eb2e8f9f7 28 *
<> 144:ef7eb2e8f9f7 29 * @Note Synchronization level: Interrupt safe
<> 144:ef7eb2e8f9f7 30 *
<> 144:ef7eb2e8f9f7 31 * Example
<> 144:ef7eb2e8f9f7 32 * @code
<> 144:ef7eb2e8f9f7 33 * // Fade a led on.
<> 144:ef7eb2e8f9f7 34 * #include "mbed.h"
<> 144:ef7eb2e8f9f7 35 *
<> 144:ef7eb2e8f9f7 36 * PwmOut led(LED1);
<> 144:ef7eb2e8f9f7 37 *
<> 144:ef7eb2e8f9f7 38 * int main() {
<> 144:ef7eb2e8f9f7 39 * while(1) {
<> 144:ef7eb2e8f9f7 40 * led = led + 0.01;
<> 144:ef7eb2e8f9f7 41 * wait(0.2);
<> 144:ef7eb2e8f9f7 42 * if(led == 1.0) {
<> 144:ef7eb2e8f9f7 43 * led = 0;
<> 144:ef7eb2e8f9f7 44 * }
<> 144:ef7eb2e8f9f7 45 * }
<> 144:ef7eb2e8f9f7 46 * }
<> 144:ef7eb2e8f9f7 47 * @endcode
<> 144:ef7eb2e8f9f7 48 *
<> 144:ef7eb2e8f9f7 49 * @note
<> 144:ef7eb2e8f9f7 50 * On the LPC1768 and LPC2368, the PWMs all share the same
<> 144:ef7eb2e8f9f7 51 * period - if you change the period for one, you change it for all.
<> 144:ef7eb2e8f9f7 52 * Although routines that change the period maintain the duty cycle
<> 144:ef7eb2e8f9f7 53 * for its PWM, all other PWMs will require their duty cycle to be
<> 144:ef7eb2e8f9f7 54 * refreshed.
<> 144:ef7eb2e8f9f7 55 */
<> 144:ef7eb2e8f9f7 56 class PwmOut {
<> 144:ef7eb2e8f9f7 57
<> 144:ef7eb2e8f9f7 58 public:
<> 144:ef7eb2e8f9f7 59
<> 144:ef7eb2e8f9f7 60 /** Create a PwmOut connected to the specified pin
<> 144:ef7eb2e8f9f7 61 *
<> 144:ef7eb2e8f9f7 62 * @param pin PwmOut pin to connect to
<> 144:ef7eb2e8f9f7 63 */
<> 144:ef7eb2e8f9f7 64 PwmOut(PinName pin) {
<> 144:ef7eb2e8f9f7 65 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 66 pwmout_init(&_pwm, pin);
<> 144:ef7eb2e8f9f7 67 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 68 }
<> 144:ef7eb2e8f9f7 69
<> 144:ef7eb2e8f9f7 70 /** Set the ouput duty-cycle, specified as a percentage (float)
<> 144:ef7eb2e8f9f7 71 *
<> 144:ef7eb2e8f9f7 72 * @param value A floating-point value representing the output duty-cycle,
<> 144:ef7eb2e8f9f7 73 * specified as a percentage. The value should lie between
<> 144:ef7eb2e8f9f7 74 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
<> 144:ef7eb2e8f9f7 75 * Values outside this range will be saturated to 0.0f or 1.0f.
<> 144:ef7eb2e8f9f7 76 */
<> 144:ef7eb2e8f9f7 77 void write(float value) {
<> 144:ef7eb2e8f9f7 78 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 79 pwmout_write(&_pwm, value);
<> 144:ef7eb2e8f9f7 80 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 81 }
<> 144:ef7eb2e8f9f7 82
<> 144:ef7eb2e8f9f7 83 /** Return the current output duty-cycle setting, measured as a percentage (float)
<> 144:ef7eb2e8f9f7 84 *
<> 144:ef7eb2e8f9f7 85 * @returns
<> 144:ef7eb2e8f9f7 86 * A floating-point value representing the current duty-cycle being output on the pin,
<> 144:ef7eb2e8f9f7 87 * measured as a percentage. The returned value will lie between
<> 144:ef7eb2e8f9f7 88 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
<> 144:ef7eb2e8f9f7 89 *
<> 144:ef7eb2e8f9f7 90 * @note
<> 144:ef7eb2e8f9f7 91 * This value may not match exactly the value set by a previous <write>.
<> 144:ef7eb2e8f9f7 92 */
<> 144:ef7eb2e8f9f7 93 float read() {
<> 144:ef7eb2e8f9f7 94 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 95 float val = pwmout_read(&_pwm);
<> 144:ef7eb2e8f9f7 96 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 97 return val;
<> 144:ef7eb2e8f9f7 98 }
<> 144:ef7eb2e8f9f7 99
<> 144:ef7eb2e8f9f7 100 /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 101 *
<> 144:ef7eb2e8f9f7 102 * @note
<> 144:ef7eb2e8f9f7 103 * The resolution is currently in microseconds; periods smaller than this
<> 144:ef7eb2e8f9f7 104 * will be set to zero.
<> 144:ef7eb2e8f9f7 105 */
<> 144:ef7eb2e8f9f7 106 void period(float seconds) {
<> 144:ef7eb2e8f9f7 107 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 108 pwmout_period(&_pwm, seconds);
<> 144:ef7eb2e8f9f7 109 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 110 }
<> 144:ef7eb2e8f9f7 111
<> 144:ef7eb2e8f9f7 112 /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 113 */
<> 144:ef7eb2e8f9f7 114 void period_ms(int ms) {
<> 144:ef7eb2e8f9f7 115 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 116 pwmout_period_ms(&_pwm, ms);
<> 144:ef7eb2e8f9f7 117 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 118 }
<> 144:ef7eb2e8f9f7 119
<> 144:ef7eb2e8f9f7 120 /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 121 */
<> 144:ef7eb2e8f9f7 122 void period_us(int us) {
<> 144:ef7eb2e8f9f7 123 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 124 pwmout_period_us(&_pwm, us);
<> 144:ef7eb2e8f9f7 125 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 126 }
<> 144:ef7eb2e8f9f7 127
<> 144:ef7eb2e8f9f7 128 /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
<> 144:ef7eb2e8f9f7 129 */
<> 144:ef7eb2e8f9f7 130 void pulsewidth(float seconds) {
<> 144:ef7eb2e8f9f7 131 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 132 pwmout_pulsewidth(&_pwm, seconds);
<> 144:ef7eb2e8f9f7 133 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 134 }
<> 144:ef7eb2e8f9f7 135
<> 144:ef7eb2e8f9f7 136 /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
<> 144:ef7eb2e8f9f7 137 */
<> 144:ef7eb2e8f9f7 138 void pulsewidth_ms(int ms) {
<> 144:ef7eb2e8f9f7 139 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 140 pwmout_pulsewidth_ms(&_pwm, ms);
<> 144:ef7eb2e8f9f7 141 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 142 }
<> 144:ef7eb2e8f9f7 143
<> 144:ef7eb2e8f9f7 144 /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
<> 144:ef7eb2e8f9f7 145 */
<> 144:ef7eb2e8f9f7 146 void pulsewidth_us(int us) {
<> 144:ef7eb2e8f9f7 147 core_util_critical_section_enter();
<> 144:ef7eb2e8f9f7 148 pwmout_pulsewidth_us(&_pwm, us);
<> 144:ef7eb2e8f9f7 149 core_util_critical_section_exit();
<> 144:ef7eb2e8f9f7 150 }
<> 144:ef7eb2e8f9f7 151
<> 144:ef7eb2e8f9f7 152 /** A operator shorthand for write()
<> 144:ef7eb2e8f9f7 153 */
<> 144:ef7eb2e8f9f7 154 PwmOut& operator= (float value) {
<> 144:ef7eb2e8f9f7 155 // Underlying call is thread safe
<> 144:ef7eb2e8f9f7 156 write(value);
<> 144:ef7eb2e8f9f7 157 return *this;
<> 144:ef7eb2e8f9f7 158 }
<> 144:ef7eb2e8f9f7 159
<> 144:ef7eb2e8f9f7 160 PwmOut& operator= (PwmOut& rhs) {
<> 144:ef7eb2e8f9f7 161 // Underlying call is thread safe
<> 144:ef7eb2e8f9f7 162 write(rhs.read());
<> 144:ef7eb2e8f9f7 163 return *this;
<> 144:ef7eb2e8f9f7 164 }
<> 144:ef7eb2e8f9f7 165
<> 144:ef7eb2e8f9f7 166 /** An operator shorthand for read()
<> 144:ef7eb2e8f9f7 167 */
<> 144:ef7eb2e8f9f7 168 operator float() {
<> 144:ef7eb2e8f9f7 169 // Underlying call is thread safe
<> 144:ef7eb2e8f9f7 170 return read();
<> 144:ef7eb2e8f9f7 171 }
<> 144:ef7eb2e8f9f7 172
<> 144:ef7eb2e8f9f7 173 protected:
<> 144:ef7eb2e8f9f7 174 pwmout_t _pwm;
<> 144:ef7eb2e8f9f7 175 };
<> 144:ef7eb2e8f9f7 176
<> 144:ef7eb2e8f9f7 177 } // namespace mbed
<> 144:ef7eb2e8f9f7 178
<> 144:ef7eb2e8f9f7 179 #endif
<> 144:ef7eb2e8f9f7 180
<> 144:ef7eb2e8f9f7 181 #endif