package com.pi4j.gpio.extension.mcp;
import java.io.IOException;
import com.pi4j.io.gpio.GpioProvider;
import com.pi4j.io.gpio.GpioProviderBase;
import com.pi4j.io.gpio.Pin;
import com.pi4j.io.gpio.PinMode;
import com.pi4j.io.gpio.PinPullResistance;
import com.pi4j.io.gpio.PinState;
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.InvalidPinModeException;
import com.pi4j.io.gpio.exception.UnsupportedPinModeException;
import com.pi4j.io.gpio.exception.UnsupportedPinPullResistanceException;
import com.pi4j.wiringpi.Spi;
/*
* #%L
* **********************************************************************
* ORGANIZATION : Pi4J
* PROJECT : Pi4J :: GPIO Extension
* FILENAME : MCP23S17GpioProvider.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 - 2013 Pi4J
* %%
* Licensed under the Apache License, Version 2.0 (the "License"); you
* may not use this file except in compliance with the License. You may obtain a copy of the License
* at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
* #L%
*/
/**
* <p>
* This GPIO provider implements the MCP23S17 SPI 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
* </p>
*
* <p>
* The MCP23S17 is connected via SPI connection to the Raspberry Pi and provides 16 GPIO pins that
* can be used for either digital input or digital output pins.
* </p>
*
* @author Robert Savage
*
*/
public class MCP23S17GpioProvider extends GpioProviderBase implements GpioProvider {
public static final String NAME = "com.pi4j.gpio.extension.mcp.MCP23S17GpioProvider";
public static final String DESCRIPTION = "MCP23S17 GPIO Provider";
public static final byte DEFAULT_ADDRESS = 0b01000000; // 0x40
private static final byte REGISTER_IODIR_A = 0x00;
private static final byte REGISTER_IODIR_B = 0x01;
private static final byte REGISTER_GPINTEN_A = 0x04;
private static final byte REGISTER_GPINTEN_B = 0x05;
private static final byte REGISTER_DEFVAL_A = 0x06;
private static final byte REGISTER_DEFVAL_B = 0x07;
private static final byte REGISTER_INTCON_A = 0x08;
private static final byte REGISTER_INTCON_B = 0x09;
private static final byte REGISTER_GPPU_A = 0x0C;
private static final byte REGISTER_GPPU_B = 0x0D;
private static final byte REGISTER_INTF_A = 0x0E;
private static final byte REGISTER_INTF_B = 0x0F;
// private static final byte REGISTER_INTCAP_A = 0x10;
// private static final byte REGISTER_INTCAP_B = 0x11;
private static final byte REGISTER_GPIO_A = 0x12;
private static final byte 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 byte address = DEFAULT_ADDRESS;
private GpioStateMonitor monitor = null;
public static final int SPI_SPEED = 1000000;
public static final byte WRITE_FLAG = 0b00000000; // 0x00
public static final byte READ_FLAG = 0b00000001; // 0x01
public MCP23S17GpioProvider(byte spiAddress, int spiChannel) throws IOException {
this(spiAddress, spiChannel, SPI_SPEED);
}
public MCP23S17GpioProvider(byte spiAddress, int spiChannel, int spiSpeed) throws IOException {
// setup SPI for communication
int fd = Spi.wiringPiSPISetup(spiChannel, spiSpeed);
if (fd <= -1) {
throw new IOException("SPI port setup failed.");
}
// set all default pins directions
write(REGISTER_IODIR_A, (byte) currentDirectionA);
write(REGISTER_IODIR_B, (byte) currentDirectionB);
// set all default pin interrupts
write(REGISTER_GPINTEN_A, (byte) currentDirectionA);
write(REGISTER_GPINTEN_B, (byte) currentDirectionB);
// set all default pin interrupt default values
write(REGISTER_DEFVAL_A, (byte) 0x00);
write(REGISTER_DEFVAL_B, (byte) 0x00);
// set all default pin interrupt comparison behaviors
write(REGISTER_INTCON_A, (byte) 0x00);
write(REGISTER_INTCON_B, (byte) 0x00);
// set all default pin states
write(REGISTER_GPIO_A, (byte) currentStatesA);
write(REGISTER_GPIO_B, (byte) currentStatesB);
// set all default pin pull up resistors
write(REGISTER_GPPU_A, (byte) currentPullupA);
write(REGISTER_GPPU_B, (byte) currentPullupB);
}
protected void write(byte register, byte data) {
// create packet in data buffer
byte packet[] = new byte[3];
packet[0] = (byte)(address|WRITE_FLAG); // address byte
packet[1] = register; // register byte
packet[2] = data; // data byte
// send data packet
Spi.wiringPiSPIDataRW(0, packet, 3);
}
protected byte read(byte register){
// create packet in data buffer
byte packet[] = new byte[3];
packet[0] = (byte)(address|READ_FLAG); // address byte
packet[1] = register; // register byte
packet[2] = 0b00000000; // data byte
int result = Spi.wiringPiSPIDataRW(0, packet, 3);
if(result >= 0)
return packet[2];
else
throw new RuntimeException("Invalid SPI read operation: " + result);
}
@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) {
// validate
if (!pin.getSupportedPinModes().contains(mode)) {
throw new InvalidPinModeException(pin, "Invalid pin mode [" + mode.getName()
+ "]; pin [" + pin.getName() + "] does not support this mode.");
}
// validate
if (!pin.getSupportedPinModes().contains(mode)) {
throw new UnsupportedPinModeException(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);
}
// cache mode
getPinCache(pin).setMode(mode);
// 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(this);
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
write(REGISTER_IODIR_A, (byte) currentDirectionA);
// enable interrupts; interrupt on any change from previous state
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
write(REGISTER_IODIR_B, (byte) currentDirectionB);
// enable interrupts; interrupt on any change from previous state
write(REGISTER_GPINTEN_B, (byte) currentDirectionB);
}
@Override
public PinMode getMode(Pin pin) {
return super.getMode(pin);
}
@Override
public void setState(Pin pin, PinState state) {
// validate
if (hasPin(pin) == false) {
throw new InvalidPinException(pin);
}
// only permit invocation on pins set to DIGITAL_OUTPUT modes
if (getPinCache(pin).getMode() != PinMode.DIGITAL_OUTPUT) {
throw new InvalidPinModeException(pin, "Invalid pin mode on pin [" + pin.getName()
+ "]; cannot setState() when pin mode is ["
+ getPinCache(pin).getMode().getName() + "]");
}
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);
}
// cache pin state
getPinCache(pin).setState(state);
}
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
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
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
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
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();
// if a monitor is running, then shut it down now
if (monitor != null) {
// shutdown monitoring thread
monitor.shutdown();
monitor = null;
}
}
/**
* This class/thread is used to to actively monitor for GPIO interrupts
*
* @author Robert Savage
*
*/
private class GpioStateMonitor extends Thread {
private MCP23S17GpioProvider provider;
private boolean shuttingDown = false;
public GpioStateMonitor(MCP23S17GpioProvider provider) {
this.provider = provider;
}
public void shutdown() {
shuttingDown = true;
}
public void run() {
while (!shuttingDown) {
try {
// only process for interrupts if a pin on port A is configured as an input pin
if (currentDirectionA > 0) {
// process interrupts for port A
byte pinInterruptA = provider.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
byte pinInterruptState = provider.read(REGISTER_GPIO_A);
// loop over the available pins on port B
for (Pin pin : MCP23S17Pin.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 = (int)provider.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 = (int)provider.read(REGISTER_GPIO_B);
// loop over the available pins on port B
for (Pin pin : MCP23S17Pin.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));
}
}
}
}
}
}