add PCF8575 support

Adafruit_PCF8574.h

@@ -18,8 +18,6 @@
 #define _ADAFRUIT_PCF8574_H
 
 #include "Arduino.h"
-#include <Wire.h>
-
 #include <Adafruit_BusIO_Register.h>
 #include <Adafruit_I2CDevice.h>
 

Adafruit_PCF8575.cpp

@@ -0,0 +1,124 @@
+/*!
+ *  @file Adafruit_PCF8575.cpp
+ *
+ *  @mainpage Adafruit PCF8575 I2C Potentiometer
+ *
+ *  @section intro_sec Introduction
+ *
+ * 	I2C Driver for the NXP PCF8575 I2C GPIO expander
+ *
+ * 	This is a library for the Adafruit PCF8575 breakout:
+ * 	http://www.adafruit.com/products
+ *
+ * 	Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit and open-source hardware by purchasing products from
+ * 	Adafruit!
+ *
+ *  @section dependencies Dependencies
+ *
+ *  This library depends on the Adafruit BusIO library
+ *
+ *  @section author Author
+ *
+ *  ladyada for Adafruit Industries
+ *
+ * 	@section license License
+ *
+ * 	BSD (see license.txt)
+ *
+ * 	@section  HISTORY
+ *
+ *     v1.0 - First release
+ */
+
+#include "Adafruit_PCF8575.h"
+
+/*!
+ *    @brief  Instantiates a new PCF8575 class
+ */
+Adafruit_PCF8575::Adafruit_PCF8575(void) {}
+
+/*!
+ *    @brief  Sets up the hardware and initializes I2C
+ *    @param  i2c_address
+ *            The I2C address to be used.
+ *    @param  wire
+ *            The Wire object to be used for I2C connections.
+ *    @return True if initialization was successful, otherwise false.
+ */
+bool Adafruit_PCF8575::begin(uint8_t i2c_address, TwoWire *wire) {
+  delete (i2c_dev);
+
+  i2c_dev = new Adafruit_I2CDevice(i2c_address, wire);
+
+  if (!i2c_dev->begin()) {
+    return false;
+  }
+
+  return true;
+}
+
+/*!
+ *    @brief  Write one 'word' of data directly to the GPIO control register
+ *    @param  d The data to write
+ *    @return True if we were able to write the data successfully over I2C
+ */
+bool Adafruit_PCF8575::digitalWriteWord(uint16_t d) {
+  _writebuf = d;
+  return i2c_dev->write((uint8_t *)&_writebuf, 2);
+}
+
+/*!
+ *    @brief  Read one 'word' of data directly from the GPIO control register
+ *    @return The byte of data read from the device
+ */
+uint16_t Adafruit_PCF8575::digitalReadWord(void) {
+  i2c_dev->read((uint8_t *)&_readbuf, 2);
+  return _readbuf;
+}
+
+/*!
+ *    @brief  Set one GPIO expander pin to 'high' (weak pullup) or 'low'
+ * (grounded)
+ *    @param  pinnum The GPIO pin number, from 0 to 7 inclusive
+ *    @param  val The boolean value to write: true means activate the pullup
+ *    and false means turn on the sinking transistor.
+ *    @return True if we were able to write the data successfully over I2C
+ */
+bool Adafruit_PCF8575::digitalWrite(uint8_t pinnum, bool val) {
+  if (val) {
+    _writebuf |= 1UL << pinnum;
+  } else {
+    _writebuf &= ~(1UL << pinnum);
+  }
+  return i2c_dev->write((uint8_t *)&_writebuf, 2);
+}
+
+/*!
+ *    @brief  Set one GPIO expander pin to 'output' (grounded) or 'input' (weak
+ * pullup)
+ *    @param  pinnum The GPIO pin number, from 0 to 15 inclusive
+ *    @param  val The value to write: INPUT or INPUT_PULLUP means activate the
+ * pullup and OUTPUT means turn on the sinking transistor, as this is an open
+ * drain device
+ *    @return True if we were able to write the data successfully over I2C
+ */
+bool Adafruit_PCF8575::pinMode(uint8_t pinnum, uint8_t val) {
+  if ((val == INPUT) || (val == INPUT_PULLUP)) {
+    _writebuf |= 1UL << pinnum;
+  } else {
+    _writebuf &= ~(1UL << pinnum);
+  }
+  return i2c_dev->write((uint8_t *)&_writebuf, 2);
+}
+
+/*!
+ *    @brief  Get a GPIO expander pin value
+ *    @param  pinnum The GPIO pin number, from 0 to 7 inclusive
+ *    @return True if the pin logic is NOT ground, false if the pin logic is
+ * ground
+ */
+bool Adafruit_PCF8575::digitalRead(uint8_t pinnum) {
+  i2c_dev->read((uint8_t *)&_readbuf, 2);
+  return (_readbuf >> pinnum) & 0x1;
+}

Adafruit_PCF8575.h

@@ -0,0 +1,47 @@
+/*!
+ *  @file Adafruit_PCF8575.h
+ *
+ * 	I2C Driver for PCF8575 I2C GPIO expander
+ *
+ * 	This is a library for the Adafruit PCF8575 breakout:
+ * 	http://www.adafruit.com/products
+ *
+ * 	Adafruit invests time and resources providing this open source code,
+ *  please support Adafruit and open-source hardware by purchasing products from
+ * 	Adafruit!
+ *
+ *
+ *	BSD license (see license.txt)
+ */
+
+#ifndef _ADAFRUIT_PCF8575_H
+#define _ADAFRUIT_PCF8575_H
+
+#include "Arduino.h"
+#include <Adafruit_BusIO_Register.h>
+#include <Adafruit_I2CDevice.h>
+
+#define PCF8575_I2CADDR_DEFAULT 0x20 ///< PCF8575 default I2C address
+
+/*!
+ *    @brief  Class that stores state and functions for interacting with
+ *            the PCF8575 I2C Expander
+ */
+class Adafruit_PCF8575 {
+public:
+  Adafruit_PCF8575();
+  bool begin(uint8_t i2c_addr = PCF8575_I2CADDR_DEFAULT, TwoWire *wire = &Wire);
+
+  bool digitalWriteWord(uint16_t d);
+  bool digitalWrite(uint8_t pinnum, bool val);
+  uint16_t digitalReadWord(void);
+  bool digitalRead(uint8_t pinnum);
+  bool pinMode(uint8_t pinnum, uint8_t val);
+
+private:
+  uint16_t _readbuf = 0, _writebuf = 0;
+
+  Adafruit_I2CDevice *i2c_dev;
+};
+
+#endif