siva surendar / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by mbed official

drivers/PwmOut.h@150:da61ba4e9755, 2016-11-25 (annotated)

Committer:
sivasuren
Date:
Fri Nov 25 07:57:40 2016 +0000
Revision:
150:da61ba4e9755
Parent:
149:156823d33999 
surendar changes

Who changed what in which revision?

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<> 149:156823d33999 1 /* mbed Microcontroller Library
<> 149:156823d33999 2 * Copyright (c) 2006-2013 ARM Limited
<> 149:156823d33999 3 *
<> 149:156823d33999 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 149:156823d33999 5 * you may not use this file except in compliance with the License.
<> 149:156823d33999 6 * You may obtain a copy of the License at
<> 149:156823d33999 7 *
<> 149:156823d33999 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 9 *
<> 149:156823d33999 10 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 149:156823d33999 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 13 * See the License for the specific language governing permissions and
<> 149:156823d33999 14 * limitations under the License.
<> 149:156823d33999 15 */
<> 149:156823d33999 16 #ifndef MBED_PWMOUT_H
<> 149:156823d33999 17 #define MBED_PWMOUT_H
<> 149:156823d33999 18
<> 149:156823d33999 19 #include "platform/platform.h"
<> 149:156823d33999 20
<> 149:156823d33999 21 #if DEVICE_PWMOUT
<> 149:156823d33999 22 #include "hal/pwmout_api.h"
<> 149:156823d33999 23 #include "platform/critical.h"
<> 149:156823d33999 24
<> 149:156823d33999 25 namespace mbed {
<> 149:156823d33999 26 /** \addtogroup drivers */
<> 149:156823d33999 27 /** @{*/
<> 149:156823d33999 28
<> 149:156823d33999 29 /** A pulse-width modulation digital output
<> 149:156823d33999 30 *
<> 149:156823d33999 31 * @Note Synchronization level: Interrupt safe
<> 149:156823d33999 32 *
<> 149:156823d33999 33 * Example
<> 149:156823d33999 34 * @code
<> 149:156823d33999 35 * // Fade a led on.
<> 149:156823d33999 36 * #include "mbed.h"
<> 149:156823d33999 37 *
<> 149:156823d33999 38 * PwmOut led(LED1);
<> 149:156823d33999 39 *
<> 149:156823d33999 40 * int main() {
<> 149:156823d33999 41 * while(1) {
<> 149:156823d33999 42 * led = led + 0.01;
<> 149:156823d33999 43 * wait(0.2);
<> 149:156823d33999 44 * if(led == 1.0) {
<> 149:156823d33999 45 * led = 0;
<> 149:156823d33999 46 * }
<> 149:156823d33999 47 * }
<> 149:156823d33999 48 * }
<> 149:156823d33999 49 * @endcode
<> 149:156823d33999 50 *
<> 149:156823d33999 51 * @note
<> 149:156823d33999 52 * On the LPC1768 and LPC2368, the PWMs all share the same
<> 149:156823d33999 53 * period - if you change the period for one, you change it for all.
<> 149:156823d33999 54 * Although routines that change the period maintain the duty cycle
<> 149:156823d33999 55 * for its PWM, all other PWMs will require their duty cycle to be
<> 149:156823d33999 56 * refreshed.
<> 149:156823d33999 57 */
<> 149:156823d33999 58 class PwmOut {
<> 149:156823d33999 59
<> 149:156823d33999 60 public:
<> 149:156823d33999 61
<> 149:156823d33999 62 /** Create a PwmOut connected to the specified pin
<> 149:156823d33999 63 *
<> 149:156823d33999 64 * @param pin PwmOut pin to connect to
<> 149:156823d33999 65 */
<> 149:156823d33999 66 PwmOut(PinName pin) {
<> 149:156823d33999 67 core_util_critical_section_enter();
<> 149:156823d33999 68 pwmout_init(&_pwm, pin);
<> 149:156823d33999 69 core_util_critical_section_exit();
<> 149:156823d33999 70 }
<> 149:156823d33999 71
<> 149:156823d33999 72 /** Set the ouput duty-cycle, specified as a percentage (float)
<> 149:156823d33999 73 *
<> 149:156823d33999 74 * @param value A floating-point value representing the output duty-cycle,
<> 149:156823d33999 75 * specified as a percentage. The value should lie between
<> 149:156823d33999 76 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
<> 149:156823d33999 77 * Values outside this range will be saturated to 0.0f or 1.0f.
<> 149:156823d33999 78 */
<> 149:156823d33999 79 void write(float value) {
<> 149:156823d33999 80 core_util_critical_section_enter();
<> 149:156823d33999 81 pwmout_write(&_pwm, value);
<> 149:156823d33999 82 core_util_critical_section_exit();
<> 149:156823d33999 83 }
<> 149:156823d33999 84
<> 149:156823d33999 85 /** Return the current output duty-cycle setting, measured as a percentage (float)
<> 149:156823d33999 86 *
<> 149:156823d33999 87 * @returns
<> 149:156823d33999 88 * A floating-point value representing the current duty-cycle being output on the pin,
<> 149:156823d33999 89 * measured as a percentage. The returned value will lie between
<> 149:156823d33999 90 * 0.0f (representing on 0%) and 1.0f (representing on 100%).
<> 149:156823d33999 91 *
<> 149:156823d33999 92 * @note
<> 149:156823d33999 93 * This value may not match exactly the value set by a previous <write>.
<> 149:156823d33999 94 */
<> 149:156823d33999 95 float read() {
<> 149:156823d33999 96 core_util_critical_section_enter();
<> 149:156823d33999 97 float val = pwmout_read(&_pwm);
<> 149:156823d33999 98 core_util_critical_section_exit();
<> 149:156823d33999 99 return val;
<> 149:156823d33999 100 }
<> 149:156823d33999 101
<> 149:156823d33999 102 /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
<> 149:156823d33999 103 *
<> 149:156823d33999 104 * @note
<> 149:156823d33999 105 * The resolution is currently in microseconds; periods smaller than this
<> 149:156823d33999 106 * will be set to zero.
<> 149:156823d33999 107 */
<> 149:156823d33999 108 void period(float seconds) {
<> 149:156823d33999 109 core_util_critical_section_enter();
<> 149:156823d33999 110 pwmout_period(&_pwm, seconds);
<> 149:156823d33999 111 core_util_critical_section_exit();
<> 149:156823d33999 112 }
<> 149:156823d33999 113
<> 149:156823d33999 114 /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
<> 149:156823d33999 115 */
<> 149:156823d33999 116 void period_ms(int ms) {
<> 149:156823d33999 117 core_util_critical_section_enter();
<> 149:156823d33999 118 pwmout_period_ms(&_pwm, ms);
<> 149:156823d33999 119 core_util_critical_section_exit();
<> 149:156823d33999 120 }
<> 149:156823d33999 121
<> 149:156823d33999 122 /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
<> 149:156823d33999 123 */
<> 149:156823d33999 124 void period_us(int us) {
<> 149:156823d33999 125 core_util_critical_section_enter();
<> 149:156823d33999 126 pwmout_period_us(&_pwm, us);
<> 149:156823d33999 127 core_util_critical_section_exit();
<> 149:156823d33999 128 }
<> 149:156823d33999 129
<> 149:156823d33999 130 /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
<> 149:156823d33999 131 */
<> 149:156823d33999 132 void pulsewidth(float seconds) {
<> 149:156823d33999 133 core_util_critical_section_enter();
<> 149:156823d33999 134 pwmout_pulsewidth(&_pwm, seconds);
<> 149:156823d33999 135 core_util_critical_section_exit();
<> 149:156823d33999 136 }
<> 149:156823d33999 137
<> 149:156823d33999 138 /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
<> 149:156823d33999 139 */
<> 149:156823d33999 140 void pulsewidth_ms(int ms) {
<> 149:156823d33999 141 core_util_critical_section_enter();
<> 149:156823d33999 142 pwmout_pulsewidth_ms(&_pwm, ms);
<> 149:156823d33999 143 core_util_critical_section_exit();
<> 149:156823d33999 144 }
<> 149:156823d33999 145
<> 149:156823d33999 146 /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
<> 149:156823d33999 147 */
<> 149:156823d33999 148 void pulsewidth_us(int us) {
<> 149:156823d33999 149 core_util_critical_section_enter();
<> 149:156823d33999 150 pwmout_pulsewidth_us(&_pwm, us);
<> 149:156823d33999 151 core_util_critical_section_exit();
<> 149:156823d33999 152 }
<> 149:156823d33999 153
<> 149:156823d33999 154 /** A operator shorthand for write()
<> 149:156823d33999 155 */
<> 149:156823d33999 156 PwmOut& operator= (float value) {
<> 149:156823d33999 157 // Underlying call is thread safe
<> 149:156823d33999 158 write(value);
<> 149:156823d33999 159 return *this;
<> 149:156823d33999 160 }
<> 149:156823d33999 161
<> 149:156823d33999 162 PwmOut& operator= (PwmOut& rhs) {
<> 149:156823d33999 163 // Underlying call is thread safe
<> 149:156823d33999 164 write(rhs.read());
<> 149:156823d33999 165 return *this;
<> 149:156823d33999 166 }
<> 149:156823d33999 167
<> 149:156823d33999 168 /** An operator shorthand for read()
<> 149:156823d33999 169 */
<> 149:156823d33999 170 operator float() {
<> 149:156823d33999 171 // Underlying call is thread safe
<> 149:156823d33999 172 return read();
<> 149:156823d33999 173 }
<> 149:156823d33999 174
<> 149:156823d33999 175 protected:
<> 149:156823d33999 176 pwmout_t _pwm;
<> 149:156823d33999 177 };
<> 149:156823d33999 178
<> 149:156823d33999 179 } // namespace mbed
<> 149:156823d33999 180
<> 149:156823d33999 181 #endif
<> 149:156823d33999 182
<> 149:156823d33999 183 #endif
<> 149:156823d33999 184
<> 149:156823d33999 185 /** @}*/