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Diff: drivers/PwmOut.h
- Revision:
- 149:156823d33999
diff -r 21d94c44109e -r 156823d33999 drivers/PwmOut.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/drivers/PwmOut.h Fri Oct 28 11:17:30 2016 +0100 @@ -0,0 +1,185 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#ifndef MBED_PWMOUT_H +#define MBED_PWMOUT_H + +#include "platform/platform.h" + +#if DEVICE_PWMOUT +#include "hal/pwmout_api.h" +#include "platform/critical.h" + +namespace mbed { +/** \addtogroup drivers */ +/** @{*/ + +/** A pulse-width modulation digital output + * + * @Note Synchronization level: Interrupt safe + * + * Example + * @code + * // Fade a led on. + * #include "mbed.h" + * + * PwmOut led(LED1); + * + * int main() { + * while(1) { + * led = led + 0.01; + * wait(0.2); + * if(led == 1.0) { + * led = 0; + * } + * } + * } + * @endcode + * + * @note + * On the LPC1768 and LPC2368, the PWMs all share the same + * period - if you change the period for one, you change it for all. + * Although routines that change the period maintain the duty cycle + * for its PWM, all other PWMs will require their duty cycle to be + * refreshed. + */ +class PwmOut { + +public: + + /** Create a PwmOut connected to the specified pin + * + * @param pin PwmOut pin to connect to + */ + PwmOut(PinName pin) { + core_util_critical_section_enter(); + pwmout_init(&_pwm, pin); + core_util_critical_section_exit(); + } + + /** Set the ouput duty-cycle, specified as a percentage (float) + * + * @param value A floating-point value representing the output duty-cycle, + * specified as a percentage. The value should lie between + * 0.0f (representing on 0%) and 1.0f (representing on 100%). + * Values outside this range will be saturated to 0.0f or 1.0f. + */ + void write(float value) { + core_util_critical_section_enter(); + pwmout_write(&_pwm, value); + core_util_critical_section_exit(); + } + + /** Return the current output duty-cycle setting, measured as a percentage (float) + * + * @returns + * A floating-point value representing the current duty-cycle being output on the pin, + * measured as a percentage. The returned value will lie between + * 0.0f (representing on 0%) and 1.0f (representing on 100%). + * + * @note + * This value may not match exactly the value set by a previous <write>. + */ + float read() { + core_util_critical_section_enter(); + float val = pwmout_read(&_pwm); + core_util_critical_section_exit(); + return val; + } + + /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same. + * + * @note + * The resolution is currently in microseconds; periods smaller than this + * will be set to zero. + */ + void period(float seconds) { + core_util_critical_section_enter(); + pwmout_period(&_pwm, seconds); + core_util_critical_section_exit(); + } + + /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same. + */ + void period_ms(int ms) { + core_util_critical_section_enter(); + pwmout_period_ms(&_pwm, ms); + core_util_critical_section_exit(); + } + + /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same. + */ + void period_us(int us) { + core_util_critical_section_enter(); + pwmout_period_us(&_pwm, us); + core_util_critical_section_exit(); + } + + /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same. + */ + void pulsewidth(float seconds) { + core_util_critical_section_enter(); + pwmout_pulsewidth(&_pwm, seconds); + core_util_critical_section_exit(); + } + + /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same. + */ + void pulsewidth_ms(int ms) { + core_util_critical_section_enter(); + pwmout_pulsewidth_ms(&_pwm, ms); + core_util_critical_section_exit(); + } + + /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same. + */ + void pulsewidth_us(int us) { + core_util_critical_section_enter(); + pwmout_pulsewidth_us(&_pwm, us); + core_util_critical_section_exit(); + } + + /** A operator shorthand for write() + */ + PwmOut& operator= (float value) { + // Underlying call is thread safe + write(value); + return *this; + } + + PwmOut& operator= (PwmOut& rhs) { + // Underlying call is thread safe + write(rhs.read()); + return *this; + } + + /** An operator shorthand for read() + */ + operator float() { + // Underlying call is thread safe + return read(); + } + +protected: + pwmout_t _pwm; +}; + +} // namespace mbed + +#endif + +#endif + +/** @}*/