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PwmOut.h
- Committer:
- JKsoft_main
- Date:
- 2018-04-17
- Revision:
- 4:1ad49e6aa728
- Parent:
- 0:e1a608bb55e8
File content as of revision 4:1ad49e6aa728:
/* 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.h" #if DEVICE_PWMOUT #include "pwmout_api.h" namespace mbed { /** A pulse-width modulation digital output * * 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) { pwmout_init(&_pwm, pin); } /** 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) { pwmout_write(&_pwm, value); } /** 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() { return pwmout_read(&_pwm); } /** 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) { pwmout_period(&_pwm, seconds); } /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same. */ void period_ms(int ms) { pwmout_period_ms(&_pwm, ms); } /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same. */ void period_us(int us) { pwmout_period_us(&_pwm, us); } /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same. */ void pulsewidth(float seconds) { pwmout_pulsewidth(&_pwm, seconds); } /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same. */ void pulsewidth_ms(int ms) { pwmout_pulsewidth_ms(&_pwm, ms); } /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same. */ void pulsewidth_us(int us) { pwmout_pulsewidth_us(&_pwm, us); } #ifdef MBED_OPERATORS /** A operator shorthand for write() */ PwmOut& operator= (float value) { write(value); return *this; } PwmOut& operator= (PwmOut& rhs) { write(rhs.read()); return *this; } /** An operator shorthand for read() */ operator float() { return read(); } #endif protected: pwmout_t _pwm; }; } // namespace mbed #endif #endif