mirror of
https://github.com/DCC-EX/CommandStation-EX.git
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103 lines
3.3 KiB
C++
103 lines
3.3 KiB
C++
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/*!
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* @file PWMServoDriver.cpp
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*
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* @mainpage Adafruit 16-channel PWM & Servo driver, based on Adafruit_PWMServoDriver
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*
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* @section intro_sec Introduction
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*
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* This is a library for the 16-channel PWM & Servo driver.
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*
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* Designed specifically to work with the Adafruit PWM & Servo driver.
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* This class contains a very small subset of the Adafruit version which
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* is relevant to driving simple servos at 50Hz through a number of chained
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* servo driver boards (ie servos 0-15 on board 0x40, 16-31 on board 0x41 etc.)
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*
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* @section author Author
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* Chris Harlow (TPL)
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* original by Limor Fried/Ladyada (Adafruit Industries).
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*
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* @section license License
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*
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* BSD license, all text above must be included in any redistribution
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*/
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#include <Arduino.h>
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#include <Wire.h>
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#include "PWMServoDriver.h"
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#include "DIAG.h"
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// REGISTER ADDRESSES
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const byte PCA9685_MODE1=0x00; // Mode Register
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const byte PCA9685_FIRST_SERVO=0x06; /** low byte first servo register ON*/
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const byte PCA9685_PRESCALE=0xFE; /** Prescale register for PWM output frequency */
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// MODE1 bits
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const byte MODE1_SLEEP=0x10; /**< Low power mode. Oscillator off */
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const byte MODE1_AI=0x20; /**< Auto-Increment enabled */
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const byte MODE1_RESTART=0x80; /**< Restart enabled */
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const byte PCA9685_I2C_ADDRESS=0x40; /** First PCA9685 I2C Slave Address */
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const float FREQUENCY_OSCILLATOR=25000000.0; /** Accurate enough for our purposes */
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const uint8_t PRESCALE_50HZ = (uint8_t)(((FREQUENCY_OSCILLATOR / (50.0 * 4096.0)) + 0.5) - 1);
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/*!
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* @brief Sets the PWM frequency for a chip to 50Hz for servos
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*/
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byte PWMServoDriver::setupFlags=0; // boards that have been initialised
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byte PWMServoDriver::failFlags=0; // boards that have faild initialisation
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bool PWMServoDriver::setup(int board) {
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if (board>3 || (failFlags & (1<<board))) return false;
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if (setupFlags & (1<<board)) return true;
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Wire.begin();
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uint8_t i2caddr=PCA9685_I2C_ADDRESS + board;
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// Terst if device is available
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Wire.beginTransmission(i2caddr);
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byte error = Wire.endTransmission();
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if (error!=0) {
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DIAG(F("\nI2C Servo device 0x%x Not Found %d\n"),i2caddr, error);
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failFlags|=1<<board;
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return false;
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}
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//DIAG(F("\nPWMServoDriver::setup %x prescale=%d"),i2caddr,PRESCALE_50HZ);
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writeRegister(i2caddr,PCA9685_MODE1, MODE1_SLEEP | MODE1_AI);
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writeRegister(i2caddr,PCA9685_PRESCALE, PRESCALE_50HZ);
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writeRegister(i2caddr,PCA9685_MODE1,MODE1_AI);
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writeRegister(i2caddr,PCA9685_MODE1, MODE1_RESTART | MODE1_AI);
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setupFlags|=1<<board;
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return true;
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}
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/*!
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* @brief Sets the PWM output to a servo
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*/
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void PWMServoDriver::setServo(byte servoNum, uint16_t value) {
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int board=servoNum/16;
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int pin=servoNum%16;
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if (setup(board)) {
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DIAG(F("\nSetServo %d %d\n"),servoNum,value);
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Wire.beginTransmission(PCA9685_I2C_ADDRESS + board);
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Wire.write(PCA9685_FIRST_SERVO + 4 * pin); // 4 registers per pin
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Wire.write(0);
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Wire.write(0);
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Wire.write(value);
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Wire.write(value >> 8);
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byte error=Wire.endTransmission();
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if (error!=0) DIAG(F("\nSetServo error %d\n"),error);
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}
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}
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void PWMServoDriver::writeRegister(uint8_t i2caddr,uint8_t hardwareRegister, uint8_t d) {
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Wire.beginTransmission(i2caddr);
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Wire.write(hardwareRegister);
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Wire.write(d);
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Wire.endTransmission();
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delay(5); // allow registers to settle before continuing
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}
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