PCA9685.h

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/****************************************************************************
 *
 *   Copyright (c) 2017 PX4 Development Team. All rights reserved.
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 * 1. Redistributions of source code must retain the above copyright
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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 *
 * Original Author      : Georgi Todorov
 * Edited by    : Tord Wessman
 * Created on  : Nov 22, 2013
 * Rewrite     : Fan.zhang  421395590@qq.com
 * Updated on  : Mar 2, 2017
 ****************************************************************************/

#pragma once
#include <inttypes.h>
#include "common.h"

namespace linux_pwm_out
{

// Register Definitions
// 寄存器定义
#define MODE1 0x00          //Mode  register  1
#define MODE2 0x01          //Mode  register  2
#define SUBADR1 0x02        //I2C-bus subaddress 1
#define SUBADR2 0x03        //I2C-bus subaddress 2
#define SUBADR3 0x04        //I2C-bus subaddress 3
#define ALLCALLADR 0x05     //LED All Call I2C-bus address
#define LED0 0x6            //LED0 start register
#define LED0_ON_L 0x6       //LED0 output and brightness control byte 0
#define LED0_ON_H 0x7       //LED0 output and brightness control byte 1
#define LED0_OFF_L 0x8      //LED0 output and brightness control byte 2
#define LED0_OFF_H 0x9      //LED0 output and brightness control byte 3
#define LED_MULTIPLYER 4    // For the other 15 channels
#define ALLLED_ON_L 0xFA    //load all the LEDn_ON registers, byte 0 (turn 0-7 channels on)
#define ALLLED_ON_H 0xFB    //load all the LEDn_ON registers, byte 1 (turn 8-15 channels on)
#define ALLLED_OFF_L 0xFC   //load all the LEDn_OFF registers, byte 0 (turn 0-7 channels off)
#define ALLLED_OFF_H 0xFD   //load all the LEDn_OFF registers, byte 1 (turn 8-15 channels off)
#define PRE_SCALE 0xFE      //prescaler for output frequency
#define MAX_PWM_RES 4096        //Resolution 4096=12bit 分辨率，按2的阶乘计算，12bit为4096
#define CLOCK_FREQ 25000000.0 //25MHz default osc clock
#define PCA9685_DEFAULT_I2C_ADDR 0x40  // default i2c address for pca9685 默认i2c地址为0x40
#define PCA9685_DEFAULT_I2C_BUS  1     // default i2c bus for pca9685  默认为1

//! Main class that exports features for PCA9685 chip
class PCA9685 : public PWMOutBase
{
public:

    PCA9685();

    /**
     * Constructor takes bus and address arguments
     * @param bus the bus to use in /dev/i2c-%d.
     * @param address the device address on bus
     */
    PCA9685(int bus, int address);

    int init() override { return _fd >= 0 ? 0 : -1; }

    int send_output_pwm(const uint16_t *pwm, int num_outputs) override;


    int init(int bus, int address);
    virtual ~PCA9685();

    /** Sets PCA9685 mode to 00 */
    void reset();

    /**
     * Set the frequency of PWM
     * @param freq desired frequency. 40Hz to 1000Hz using internal 25MHz oscillator.
     */
    void setPWMFreq(int freq);

    /**
     * PWM a single channel with custom on time.
     * send pwm vale to led(channel)
     * @param channel
     * @param on_value 0-4095 value to turn on the pulse
     * @param off_value 0-4095 value to turn off the pulse
     */
    void setPWM(uint8_t channel, int on_value, int off_value);

    /**
     * send pwm value to led(channel),
     * value should be range of 0-4095
     */
    void setPWM(uint8_t channel, int value);

private:
    int _fd = -1; ///< I2C device file descriptor

    /**
     * Read a single byte from PCA9685
     * @param fd file descriptor for I/O
     * @param address register address to read from
     * @return read byte
     */
    uint8_t read_byte(int fd, uint8_t address);

    /**
     *  Write a single byte to PCA9685
     * @param fd file descriptor for I/O
     * @param address register address to write to
     * @param data 8 bit data to write
     */
    void write_byte(int fd, uint8_t address, uint8_t data);

    /**
     * Open device file for PCA9685 I2C bus
     * @return fd returns the file descriptor number or -1 on error
     */
    int open_fd(int bus, int address);
};

}