com.pi4j.gpio.extension.mcp.MCP23017GpioProvider Maven / Gradle / Ivy
package com.pi4j.gpio.extension.mcp;
import com.pi4j.io.gpio.*;
import com.pi4j.io.gpio.event.PinDigitalStateChangeEvent;
import com.pi4j.io.gpio.event.PinListener;
import com.pi4j.io.gpio.exception.InvalidPinException;
import com.pi4j.io.gpio.exception.UnsupportedPinPullResistanceException;
import com.pi4j.io.i2c.I2CBus;
import com.pi4j.io.i2c.I2CDevice;
import com.pi4j.io.i2c.I2CFactory;
import java.io.IOException;
/*
* #%L
* **********************************************************************
* ORGANIZATION : Pi4J
* PROJECT : Pi4J :: GPIO Extension
* FILENAME : MCP23017GpioProvider.java
*
* This file is part of the Pi4J project. More information about
* this project can be found here: http://www.pi4j.com/
* **********************************************************************
* %%
* Copyright (C) 2012 - 2015 Pi4J
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
/**
*
* This GPIO provider implements the MCP23017 I2C GPIO expansion board as native Pi4J GPIO pins.
* More information about the board can be found here: *
* http://ww1.microchip.com/downloads/en/DeviceDoc/21952b.pdf
* http://learn.adafruit.com/mcp230xx-gpio-expander-on-the-raspberry-pi/overview
*
*
*
* The MCP23017 is connected via I2C connection to the Raspberry Pi and provides 16 GPIO pins that
* can be used for either digital input or digital output pins.
*
*
* @author Robert Savage
*
*/
public class MCP23017GpioProvider extends GpioProviderBase implements GpioProvider {
public static final String NAME = "com.pi4j.gpio.extension.mcp.MCP23017GpioProvider";
public static final String DESCRIPTION = "MCP23017 GPIO Provider";
public static final int DEFAULT_ADDRESS = 0x20;
private static final int REGISTER_IODIR_A = 0x00;
private static final int REGISTER_IODIR_B = 0x01;
private static final int REGISTER_GPINTEN_A = 0x04;
private static final int REGISTER_GPINTEN_B = 0x05;
private static final int REGISTER_DEFVAL_A = 0x06;
private static final int REGISTER_DEFVAL_B = 0x07;
private static final int REGISTER_INTCON_A = 0x08;
private static final int REGISTER_INTCON_B = 0x09;
private static final int REGISTER_GPPU_A = 0x0C;
private static final int REGISTER_GPPU_B = 0x0D;
private static final int REGISTER_INTF_A = 0x0E;
private static final int REGISTER_INTF_B = 0x0F;
// private static final int REGISTER_INTCAP_A = 0x10;
// private static final int REGISTER_INTCAP_B = 0x11;
private static final int REGISTER_GPIO_A = 0x12;
private static final int REGISTER_GPIO_B = 0x13;
private static final int GPIO_A_OFFSET = 0;
private static final int GPIO_B_OFFSET = 1000;
private int currentStatesA = 0;
private int currentStatesB = 0;
private int currentDirectionA = 0;
private int currentDirectionB = 0;
private int currentPullupA = 0;
private int currentPullupB = 0;
private boolean i2cBusOwner = false;
private final I2CBus bus;
private final I2CDevice device;
private GpioStateMonitor monitor = null;
public MCP23017GpioProvider(int busNumber, int address) throws IOException {
// create I2C communications bus instance
this(I2CFactory.getInstance(busNumber), address);
i2cBusOwner = true;
}
public MCP23017GpioProvider(I2CBus bus, int address) throws IOException {
// set reference to I2C communications bus instance
this.bus = bus;
// create I2C device instance
device = bus.getDevice(address);
// read initial GPIO pin states
currentStatesA = device.read(REGISTER_GPIO_A);
currentStatesB = device.read(REGISTER_GPIO_B);
// set all default pins directions
device.write(REGISTER_IODIR_A, (byte) currentDirectionA);
device.write(REGISTER_IODIR_B, (byte) currentDirectionB);
// set all default pin interrupts
device.write(REGISTER_GPINTEN_A, (byte) currentDirectionA);
device.write(REGISTER_GPINTEN_B, (byte) currentDirectionB);
// set all default pin interrupt default values
device.write(REGISTER_DEFVAL_A, (byte) 0x00);
device.write(REGISTER_DEFVAL_B, (byte) 0x00);
// set all default pin interrupt comparison behaviors
device.write(REGISTER_INTCON_A, (byte) 0x00);
device.write(REGISTER_INTCON_B, (byte) 0x00);
// set all default pin states
device.write(REGISTER_GPIO_A, (byte) currentStatesA);
device.write(REGISTER_GPIO_B, (byte) currentStatesB);
// set all default pin pull up resistors
device.write(REGISTER_GPPU_A, (byte) currentPullupA);
device.write(REGISTER_GPPU_B, (byte) currentPullupB);
}
@Override
public String getName() {
return NAME;
}
@Override
public void export(Pin pin, PinMode mode) {
// make sure to set the pin mode
super.export(pin, mode);
setMode(pin, mode);
}
@Override
public void unexport(Pin pin) {
super.unexport(pin);
setMode(pin, PinMode.DIGITAL_OUTPUT);
}
@Override
public void setMode(Pin pin, PinMode mode) {
super.setMode(pin, mode);
// determine A or B port based on pin address
try {
if (pin.getAddress() < GPIO_B_OFFSET) {
setModeA(pin, mode);
} else {
setModeB(pin, mode);
}
} catch (IOException ex) {
throw new RuntimeException(ex);
}
// if any pins are configured as input pins, then we need to start the interrupt monitoring
// thread
if (currentDirectionA > 0 || currentDirectionB > 0) {
// if the monitor has not been started, then start it now
if (monitor == null) {
// start monitoring thread
monitor = new GpioStateMonitor(device);
monitor.start();
}
} else {
// shutdown and destroy monitoring thread since there are no input pins configured
if (monitor != null) {
monitor.shutdown();
monitor = null;
}
}
}
private void setModeA(Pin pin, PinMode mode) throws IOException {
// determine register and pin address
int pinAddress = pin.getAddress() - GPIO_A_OFFSET;
// determine update direction value based on mode
if (mode == PinMode.DIGITAL_INPUT) {
currentDirectionA |= pinAddress;
} else if (mode == PinMode.DIGITAL_OUTPUT) {
currentDirectionA &= ~pinAddress;
}
// next update direction value
device.write(REGISTER_IODIR_A, (byte) currentDirectionA);
// enable interrupts; interrupt on any change from previous state
device.write(REGISTER_GPINTEN_A, (byte) currentDirectionA);
}
private void setModeB(Pin pin, PinMode mode) throws IOException {
// determine register and pin address
int pinAddress = pin.getAddress() - GPIO_B_OFFSET;
// determine update direction value based on mode
if (mode == PinMode.DIGITAL_INPUT) {
currentDirectionB |= pinAddress;
} else if (mode == PinMode.DIGITAL_OUTPUT) {
currentDirectionB &= ~pinAddress;
}
// next update direction (mode) value
device.write(REGISTER_IODIR_B, (byte) currentDirectionB);
// enable interrupts; interrupt on any change from previous state
device.write(REGISTER_GPINTEN_B, (byte) currentDirectionB);
}
@Override
public PinMode getMode(Pin pin) {
return super.getMode(pin);
}
@Override
public void setState(Pin pin, PinState state) {
super.setState(pin, state);
try {
// determine A or B port based on pin address
if (pin.getAddress() < GPIO_B_OFFSET) {
setStateA(pin, state);
} else {
setStateB(pin, state);
}
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
private void setStateA(Pin pin, PinState state) throws IOException {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_A_OFFSET;
// determine state value for pin bit
if (state.isHigh()) {
currentStatesA |= pinAddress;
} else {
currentStatesA &= ~pinAddress;
}
// update state value
device.write(REGISTER_GPIO_A, (byte) currentStatesA);
}
private void setStateB(Pin pin, PinState state) throws IOException {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_B_OFFSET;
// determine state value for pin bit
if (state.isHigh()) {
currentStatesB |= pinAddress;
} else {
currentStatesB &= ~pinAddress;
}
// update state value
device.write(REGISTER_GPIO_B, (byte) currentStatesB);
}
@Override
public PinState getState(Pin pin) {
// call super method to perform validation on pin
PinState result = super.getState(pin);
// determine A or B port based on pin address
if (pin.getAddress() < GPIO_B_OFFSET) {
result = getStateA(pin); // get pin state
} else {
result = getStateB(pin); // get pin state
}
// return pin state
return result;
}
private PinState getStateA(Pin pin){
// determine pin address
int pinAddress = pin.getAddress() - GPIO_A_OFFSET;
// determine pin state
PinState state = (currentStatesA & pinAddress) == pinAddress ? PinState.HIGH : PinState.LOW;
// cache state
getPinCache(pin).setState(state);
return state;
}
private PinState getStateB(Pin pin){
// determine pin address
int pinAddress = pin.getAddress() - GPIO_B_OFFSET;
// determine pin state
PinState state = (currentStatesB & pinAddress) == pinAddress ? PinState.HIGH : PinState.LOW;
// cache state
getPinCache(pin).setState(state);
return state;
}
@Override
public void setPullResistance(Pin pin, PinPullResistance resistance) {
// validate
if (hasPin(pin) == false) {
throw new InvalidPinException(pin);
}
// validate
if (!pin.getSupportedPinPullResistance().contains(resistance)) {
throw new UnsupportedPinPullResistanceException(pin, resistance);
}
try {
// determine A or B port based on pin address
if (pin.getAddress() < GPIO_B_OFFSET) {
setPullResistanceA(pin, resistance);
} else {
setPullResistanceB(pin, resistance);
}
} catch (IOException ex) {
throw new RuntimeException(ex);
}
// cache resistance
getPinCache(pin).setResistance(resistance);
}
private void setPullResistanceA(Pin pin, PinPullResistance resistance) throws IOException {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_A_OFFSET;
// determine pull up value for pin bit
if (resistance == PinPullResistance.PULL_UP) {
currentPullupA |= pinAddress;
} else {
currentPullupA &= ~pinAddress;
}
// next update pull up resistor value
device.write(REGISTER_GPPU_A, (byte) currentPullupA);
}
private void setPullResistanceB(Pin pin, PinPullResistance resistance) throws IOException {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_B_OFFSET;
// determine pull up value for pin bit
if (resistance == PinPullResistance.PULL_UP) {
currentPullupB |= pinAddress;
} else {
currentPullupB &= ~pinAddress;
}
// next update pull up resistor value
device.write(REGISTER_GPPU_B, (byte) currentPullupB);
}
@Override
public PinPullResistance getPullResistance(Pin pin) {
return super.getPullResistance(pin);
}
@Override
public void shutdown() {
// prevent reentrant invocation
if(isShutdown())
return;
// perform shutdown login in base
super.shutdown();
try {
// if a monitor is running, then shut it down now
if (monitor != null) {
// shutdown monitoring thread
monitor.shutdown();
monitor = null;
}
// if we are the owner of the I2C bus, then close it
if(i2cBusOwner) {
// close the I2C bus communication
bus.close();
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* This class/thread is used to to actively monitor for GPIO interrupts
*
* @author Robert Savage
*
*/
private class GpioStateMonitor extends Thread {
private final I2CDevice device;
private boolean shuttingDown = false;
public GpioStateMonitor(I2CDevice device) {
this.device = device;
}
public void shutdown() {
shuttingDown = true;
}
@Override
public void run() {
while (!shuttingDown) {
try {
synchronized (MCP23017GpioProvider.class) {
// only process for interrupts if a pin on port A is configured as an input pin
if (currentDirectionA > 0) {
// process interrupts for port A
int pinInterruptA = device.read(REGISTER_INTF_A);
// validate that there is at least one interrupt active on port A
if (pinInterruptA > 0) {
// read the current pin states on port A
int pinInterruptState = device.read(REGISTER_GPIO_A);
// loop over the available pins on port B
for (Pin pin : MCP23017Pin.ALL_A_PINS) {
int pinAddressA = pin.getAddress() - GPIO_A_OFFSET;
// is there an interrupt flag on this pin?
//if ((pinInterruptA & pinAddressA) > 0) {
// System.out.println("INTERRUPT ON PIN [" + pin.getName() + "]");
evaluatePinForChangeA(pin, pinInterruptState);
//}
}
}
}
// only process for interrupts if a pin on port B is configured as an input pin
if (currentDirectionB > 0) {
// process interrupts for port B
int pinInterruptB = device.read(REGISTER_INTF_B);
// validate that there is at least one interrupt active on port B
if (pinInterruptB > 0) {
// read the current pin states on port B
int pinInterruptState = device.read(REGISTER_GPIO_B);
// loop over the available pins on port B
for (Pin pin : MCP23017Pin.ALL_B_PINS) {
int pinAddressB = pin.getAddress() - GPIO_B_OFFSET;
// is there an interrupt flag on this pin?
//if ((pinInterruptB & pinAddressB) > 0) {
// System.out.println("INTERRUPT ON PIN [" + pin.getName() + "]");
evaluatePinForChangeB(pin, pinInterruptState);
//}
}
}
}
}
// ... lets take a short breather ...
Thread.currentThread();
Thread.sleep(50);
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
private void evaluatePinForChangeA(Pin pin, int state) {
if (getPinCache(pin).isExported()) {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_A_OFFSET;
if ((state & pinAddress) != (currentStatesA & pinAddress)) {
PinState newState = (state & pinAddress) == pinAddress ? PinState.HIGH
: PinState.LOW;
// cache state
getPinCache(pin).setState(newState);
// determine and cache state value for pin bit
if (newState.isHigh()) {
currentStatesA |= pinAddress;
} else {
currentStatesA &= ~pinAddress;
}
// change detected for INPUT PIN
// System.out.println("<<< CHANGE >>> " + pin.getName() + " : " + state);
dispatchPinChangeEvent(pin.getAddress(), newState);
}
}
}
private void evaluatePinForChangeB(Pin pin, int state) {
if (getPinCache(pin).isExported()) {
// determine pin address
int pinAddress = pin.getAddress() - GPIO_B_OFFSET;
if ((state & pinAddress) != (currentStatesB & pinAddress)) {
PinState newState = (state & pinAddress) == pinAddress ? PinState.HIGH
: PinState.LOW;
// cache state
getPinCache(pin).setState(newState);
// determine and cache state value for pin bit
if (newState.isHigh()) {
currentStatesB |= pinAddress;
} else {
currentStatesB &= ~pinAddress;
}
// change detected for INPUT PIN
// System.out.println("<<< CHANGE >>> " + pin.getName() + " : " + state);
dispatchPinChangeEvent(pin.getAddress(), newState);
}
}
}
private void dispatchPinChangeEvent(int pinAddress, PinState state) {
// iterate over the pin listeners map
for (Pin pin : listeners.keySet()) {
// System.out.println("<<< DISPATCH >>> " + pin.getName() + " : " +
// state.getName());
// dispatch this event to the listener
// if a matching pin address is found
if (pin.getAddress() == pinAddress) {
// dispatch this event to all listener handlers
for (PinListener listener : listeners.get(pin)) {
listener.handlePinEvent(new PinDigitalStateChangeEvent(this, pin, state));
}
}
}
}
}
}