133 lines
3.4 KiB
C++
133 lines
3.4 KiB
C++
/*
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* Originally from mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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* Copyright (c) 2014 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <stdio.h>
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#include <fcntl.h>
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namespace maa {
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/** A PWM object, used for interacting with PWM output.
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*
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* Example:
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* @code
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* // Set up PWM object then cycle percentage 0-100.
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*
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* #include "maa.h"
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*
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* PWM pwm(3);
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*
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* int main() {
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* pwm.period_us(7968750i); //Max Galileo Rev D
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* pwm.enable(1);
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*
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* float value = 0;
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* while(1) {
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* pwm.write(value);
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* sleep(0.5);
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* if(value == 1.0) {
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* value = 0;
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* } else {
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* value = value +0.1;
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* }
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* }
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* }
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* @endcode
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*/
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class PWM {
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private:
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int chipid, pin;
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FILE *duty_fp;
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void write_period(int period);
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void write_duty(int duty);
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int setup_duty_fp();
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int get_period();
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int get_duty();
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public:
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/** Create an PWM object
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*
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* @param chipid The chip in which the following pin is on.
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* @param pin The PWM channel to operate on
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*/
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PWM(int chipid, int pin);
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/** Set the ouput duty-cycle percentage, as a float
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*
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* @param percentage A floating-point value representing percentage of output.
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* The value should lie between 0.0f (representing on 0%) and 1.0f
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* Values above or below this range will be set at either 0.0f or 1.0f.
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*/
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void write(float percentage);
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/** Read the ouput duty-cycle percentage, as a float
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*
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* @return percentage A floating-point value representing percentage of output.
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* The value should lie between 0.0f (representing on 0%) and 1.0f
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* Values above or below this range will be set at either 0.0f or 1.0f.
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*/
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float read();
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/** Set the PWM period as seconds represented in a float
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*
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* @param seconds Peroid represented as a float in seconds.
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*/
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void period(float seconds);
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/** Set period. milli-oseconds.
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* @param ms milli-seconds for period.
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*/
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void period_ms(int ms);
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/** Set period. microseconds
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* @param ns microseconds as period.
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*/
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void period_us(int us);
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/** Set pulsewidth, As represnted by seconds in a (float).
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* @param seconds The duration of a pulse
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*/
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void pulsewidth(float seconds);
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/** Set pulsewidth. Milliseconds
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* @param ms milliseconds for pulsewidth.
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*/
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void pulsewidth_ms(int ms);
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/** Set pulsewidth, microseconds.
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* @param us microseconds for pulsewidth.
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*/
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void pulsewidth_us(int us);
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/** Set the enable status of the PWM pin. None zero will assume on with output being driven.
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* and 0 will disable the output.
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* @param enable enable status of pin
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*/
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void enable(int enable);
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/** Close and unexport the PWM pin.
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*/
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void close();
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};
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}
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