Raspberry PI - i2c 통신 - PCA9685

출처 : Raspberry Pi SPI and I2C Tutorial
Use the Adafruit PCA9685 with a Raspberry PI, in Java Raspberry PI to drive up to 16 servos
JavaScript Robotics: Servo - PCA9685

I2C on Pi

$ sudo raspi-config

i2c device 활성화

$ sudo vi /etc/modules

# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

i2c-bcm2708
i2c-dev

gpio commands

$ gpio -v
gpio version: 2.32
Copyright (c) 2012-2015 Gordon Henderson
This is free software with ABSOLUTELY NO WARRANTY.
For details type: gpio -warranty
 
Raspberry Pi Details:
  Type: Model B, Revision: 03, Memory: 512MB, Maker: Egoman 
  * Device tree is enabled.
  * This Raspberry Pi supports user-level GPIO access.
    -> See the man-page for more details
    -> ie. export WIRINGPI_GPIOMEM=1
$ gpio readall
 +-----+-----+---------+------+---+-Model B2-+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 | ALT0 | 1 |  3 || 4  |   |      | 5V      |     |     |
 |   3 |   9 |   SCL.1 | ALT0 | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 1 | ALT0 | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | ALT0 | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 0 | IN   | GPIO. 1 | 1   | 18  |
 |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
 |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
 |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
 |  10 |  12 |    MOSI | ALT0 | 0 | 19 || 20 |   |      | 0v      |     |     |
 |   9 |  13 |    MISO | ALT0 | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
 |  11 |  14 |    SCLK | ALT0 | 0 | 23 || 24 | 1 | OUT  | CE0     | 10  | 8   |
 |     |     |      0v |      |   | 25 || 26 | 1 | OUT  | CE1     | 11  | 7   |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |  28 |  17 | GPIO.17 |   IN | 0 | 51 || 52 | 0 | IN   | GPIO.18 | 18  | 29  |
 |  30 |  19 | GPIO.19 |   IN | 0 | 53 || 54 | 0 | IN   | GPIO.20 | 20  | 31  |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+-Model B2-+---+------+---------+-----+-----+

detect I2C chips

출처 : i2cdetect(8): detect I2C chips - Linux man page

$ ls /dev/*i2c*
/dev/i2c-1
$ sudo apt-get install -y i2c-tools
$ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: 70 -- -- -- -- -- -- -- 

배선

PCA9685Gpio.java

출처 : wyliodrin-server-nodejs/libs/raspberrypi/java/pi4j/examples/PCA9685GpioExample.java

package com.bluexmas.arm;

import java.io.IOException;

/**
 * sudo java -cp .:pi4j-core.jar:pi4j-device.jar:pi4j-gpio-extension.jar:pi4j-service.jar com.bluexmas.arm.PCA9685Gpio
 */
import java.math.BigDecimal;

import com.pi4j.gpio.extension.pca.PCA9685GpioProvider;
import com.pi4j.gpio.extension.pca.PCA9685Pin;
import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinPwmOutput;
import com.pi4j.io.gpio.Pin;
import com.pi4j.io.i2c.I2CBus;
import com.pi4j.io.i2c.I2CFactory;
import com.pi4j.io.i2c.I2CFactory.UnsupportedBusNumberException;

public class PCA9685Gpio {
	
	private static final int SERVO_DURATION_MIN = 650;
	private static final int SERVO_DURATION_NEUTRAL = 1500;
	private static final int SERVO_DURATION_MAX = 2100;
	
	private static PCA9685Gpio instance = null;
	
	private PCA9685GpioProvider gpioProvider = null;
	
	private PCA9685Gpio() throws IOException, UnsupportedBusNumberException {		
		System.out.println("<--Pi4J--> PCA9685 PWM Example ... started.");
		// This would theoretically lead into a resolution of 5 microseconds per
		// step:
		// 4096 Steps (12 Bit)
		// T = 4096 * 0.000005s = 0.02048s
		// f = 1 / T = 48.828125
		BigDecimal frequency = new BigDecimal("48.828");
		// Correction factor: actualFreq / targetFreq
		// e.g. measured actual frequency is: 51.69 Hz
		// Calculate correction factor: 51.65 / 48.828 = 1.0578
		// --> To measure actual frequency set frequency without correction
		// factor(or set to 1)
		BigDecimal frequencyCorrectionFactor = new BigDecimal("1.0578");
		// Create custom PCA9685 GPIO provider
		I2CBus bus = I2CFactory.getInstance(I2CBus.BUS_1);
		gpioProvider = new PCA9685GpioProvider(bus, 0x40, frequency, frequencyCorrectionFactor);
		// Define outputs in use for this example
		GpioPinPwmOutput[] myOutputs = provisionPwmOutputs(gpioProvider);
		// Reset outputs
		gpioProvider.reset();
	}
	
	public static PCA9685Gpio getInstance() throws IOException, UnsupportedBusNumberException {
		if (instance==null) instance = new PCA9685Gpio();
		return instance;
	}
	
	public void setPwm(Pin pin, int duration) {
		gpioProvider.setPwm(pin, duration);
	}
	
	public void shutdown() {
		gpioProvider.shutdown();
	}
	
	private static GpioPinPwmOutput[] provisionPwmOutputs(final PCA9685GpioProvider gpioProvider) {
		GpioController gpio = GpioFactory.getInstance();
		GpioPinPwmOutput myOutputs[] = { 
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_00, "Pulse 00"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_01, "Pulse 01"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_02, "Pulse 02"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_03, "Pulse 03"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_04, "Pulse 04"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_05, "Pulse 05"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_06, "Pulse 06"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_07, "Pulse 07"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_08, "Pulse 08"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_09, "Pulse 09"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_10, "Always ON"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_11, "Always OFF"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_12, "Servo pulse MIN"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_13, "Servo pulse NEUTRAL"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_14, "Servo pulse MAX"),
				gpio.provisionPwmOutputPin(gpioProvider, PCA9685Pin.PWM_15, "not used") };
		return myOutputs;
	}

	public static void main(String[] args) throws Exception {
		
		PCA9685Gpio test = PCA9685Gpio.getInstance();
		
		test.setPwm(PCA9685Pin.PWM_00, SERVO_DURATION_MIN);
		// Set 1.5ms pulse (R/C Servo neutral position)
		Thread.sleep(2000);
		test.setPwm(PCA9685Pin.PWM_00, SERVO_DURATION_NEUTRAL);
		// Set 2.1ms pulse (R/C Servo maximum position)
		Thread.sleep(2000);
		test.setPwm(PCA9685Pin.PWM_00, SERVO_DURATION_MAX);
		Thread.sleep(2000);
		test.setPwm(PCA9685Pin.PWM_00, SERVO_DURATION_MIN);
		Thread.sleep(2000);
		test.shutdown();
	}
	
}

실행

$ sudo java -cp .:pi4j-core.jar:pi4j-gpio-extension.jar com.bluexmas.arm.PCA9685Gpio
<--Pi4J--> PCA9685 PWM Example ... started.