Revision 0:4f1c764a42d3, committed 2018-11-19

Comitter:

Komazawa_sun

Date:

Mon Nov 19 09:44:37 2018 +0000

Commit message:

Transplanted lib(https://github.com/adafruit/Adafruit-RGB-LCD-Shield-Library)

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_I2C_LCD.cpp	Mon Nov 19 09:44:37 2018 +0000
@@ -0,0 +1,401 @@
+/***************************************************
+  This is a library for the Adafruit RGB 16x2 LCD Shield
+  Pick one up at the Adafruit shop!
+  ---------> http://http://www.adafruit.com/products/714
+
+  The shield uses I2C to communicate, 2 pins are required to
+  interface
+  Adafruit invests time and resources providing this open source code,
+  please support Adafruit and open-source hardware by purchasing
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.
+  BSD license, all text above must be included in any redistribution
+ ****************************************************/
+
+
+#include "Adafruit_I2C_LCD.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+
+// When the display powers up, it is configured as follows:
+//
+// 1. Display clear
+// 2. Function set:
+//    DL = 1; 8-bit interface data
+//    N = 0; 1-line display
+//    F = 0; 5x8 dot character font
+// 3. Display on/off control:
+//    D = 0; Display off
+//    C = 0; Cursor off
+//    B = 0; Blinking off
+// 4. Entry mode set:
+//    I/D = 1; Increment by 1
+//    S = 0; No shift
+//
+// Note, however, that resetting the Arduino doesn't reset the LCD, so we
+// can't assume that its in that state when a sketch starts (and the
+// RGBLCDShield constructor is called).
+
+Adafruit_I2C_LCD::Adafruit_I2C_LCD(I2C *master, uint8_t cols, uint8_t lines, uint8_t dotsize)
+{
+    _i2c = new Adafruit_MCP23017(master);
+    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
+
+    // the I/O expander pinout
+    _rs_pin = 15;
+    _rw_pin = 14;
+    _enable_pin = 13;
+    _data_pins[0] = 12;  // really d4
+    _data_pins[1] = 11;  // really d5
+    _data_pins[2] = 10;  // really d6
+    _data_pins[3] = 9;  // really d7
+
+    _button_pins[0] = 0;
+    _button_pins[1] = 1;
+    _button_pins[2] = 2;
+    _button_pins[3] = 3;
+    _button_pins[4] = 4;
+
+    begin(cols, lines, dotsize);
+}
+
+Adafruit_I2C_LCD::~Adafruit_I2C_LCD()
+{
+    delete _i2c;
+}
+
+/********** high level commands, for the user! */
+void Adafruit_I2C_LCD::clear()
+{
+    command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
+    wait_us(2000);  // this command takes a long time!
+}
+
+void Adafruit_I2C_LCD::home()
+{
+    command(LCD_RETURNHOME);  // set cursor position to zero
+    wait_us(2000);  // this command takes a long time!
+}
+
+void Adafruit_I2C_LCD::setCursor(uint8_t col, uint8_t row)
+{
+    int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
+    if ( row > _numlines ) {
+        row = _numlines-1;    // we count rows starting w/0
+    }
+
+    command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
+}
+
+// Turn the display on/off (quickly)
+void Adafruit_I2C_LCD::noDisplay()
+{
+    _displaycontrol &= ~LCD_DISPLAYON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void Adafruit_I2C_LCD::display()
+{
+    _displaycontrol |= LCD_DISPLAYON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turns the underline cursor on/off
+void Adafruit_I2C_LCD::noCursor()
+{
+    _displaycontrol &= ~LCD_CURSORON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void Adafruit_I2C_LCD::cursor()
+{
+    _displaycontrol |= LCD_CURSORON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turn on and off the blinking cursor
+void Adafruit_I2C_LCD::noBlink()
+{
+    _displaycontrol &= ~LCD_BLINKON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void Adafruit_I2C_LCD::blink()
+{
+    _displaycontrol |= LCD_BLINKON;
+    command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// These commands scroll the display without changing the RAM
+void Adafruit_I2C_LCD::scrollDisplayLeft(void)
+{
+    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
+}
+void Adafruit_I2C_LCD::scrollDisplayRight(void)
+{
+    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
+}
+
+// This is for text that flows Left to Right
+void Adafruit_I2C_LCD::leftToRight(void)
+{
+    _displaymode |= LCD_ENTRYLEFT;
+    command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This is for text that flows Right to Left
+void Adafruit_I2C_LCD::rightToLeft(void)
+{
+    _displaymode &= ~LCD_ENTRYLEFT;
+    command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'right justify' text from the cursor
+void Adafruit_I2C_LCD::autoscroll(void)
+{
+    _displaymode |= LCD_ENTRYSHIFTINCREMENT;
+    command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'left justify' text from the cursor
+void Adafruit_I2C_LCD::noAutoscroll(void)
+{
+    _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
+    command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// Allows us to fill the first 8 CGRAM locations
+// with custom characters
+void Adafruit_I2C_LCD::createChar(uint8_t location, uint8_t charmap[])
+{
+    location &= 0x7; // we only have 8 locations 0-7
+    command(LCD_SETCGRAMADDR | (location << 3));
+    for (int i=0; i<8; i++) {
+        write(charmap[i]);
+    }
+    command(LCD_SETDDRAMADDR);  // unfortunately resets the location to 0,0
+}
+
+/*********** mid level commands, for sending data/cmds */
+
+void Adafruit_I2C_LCD::command(uint8_t value)
+{
+    send(value, LOW);
+}
+
+
+void Adafruit_I2C_LCD::write(uint8_t value)
+{
+    send(value, HIGH);
+}
+
+void Adafruit_I2C_LCD::print(char *array, size_t array_size)
+{
+    for(size_t i = 0; i < array_size; i++){
+        if(array[i] == '\0')
+            break;
+        send(array[i], HIGH);   
+    }
+}
+
+/************ low level data pushing commands **********/
+
+// little wrapper for i/o writes
+void  Adafruit_I2C_LCD::_digitalWrite(uint8_t p, uint8_t d)
+{
+    _i2c->digitalWrite(p, d);
+}
+
+// Allows to set the backlight, if the LCD backpack is used
+void Adafruit_I2C_LCD::setBacklight(uint8_t status)
+{
+    // check if i2c or SPI
+    _i2c->digitalWrite(8, ~(status >> 2) & 0x1);
+    _i2c->digitalWrite(7, ~(status >> 1) & 0x1);
+    _i2c->digitalWrite(6, ~status & 0x1);
+}
+
+// little wrapper for i/o directions
+void  Adafruit_I2C_LCD::_pinMode(uint8_t p, uint8_t d)
+{
+    _i2c->pinMode(p, d);
+}
+
+void Adafruit_I2C_LCD::begin(uint8_t cols, uint8_t lines, uint8_t dotsize)
+{
+    _i2c->pinMode(8, OUTPUT);
+    _i2c->pinMode(6, OUTPUT);
+    _i2c->pinMode(7, OUTPUT);
+    setBacklight(0x7);
+
+    if (_rw_pin)
+        _i2c->pinMode(_rw_pin, OUTPUT);
+
+    _i2c->pinMode(_rs_pin, OUTPUT);
+    _i2c->pinMode(_enable_pin, OUTPUT);
+    for (uint8_t i=0; i<4; i++)
+        _i2c->pinMode(_data_pins[i], OUTPUT);
+
+    for (uint8_t i=0; i<5; i++) {
+        _i2c->pinMode(_button_pins[i], INPUT);
+        _i2c->pullUp(_button_pins[i], 1);
+    }
+
+    if (lines > 1) {
+        _displayfunction |= LCD_2LINE;
+    }
+    _numlines = lines;
+    _currline = 0;
+
+    // for some 1 line displays you can select a 10 pixel high font
+    if ((dotsize != 0) && (lines == 1)) {
+        _displayfunction |= LCD_5x10DOTS;
+    }
+
+    // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
+    // according to datasheet, we need at least 40ms after power rises above 2.7V
+    // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
+    wait_us(50000);
+    // Now we pull both RS and R/W low to begin commands
+    _digitalWrite(_rs_pin, LOW);
+    _digitalWrite(_enable_pin, LOW);
+    if (_rw_pin != 255) {
+        _digitalWrite(_rw_pin, LOW);
+    }
+
+    //put the LCD into 4 bit or 8 bit mode
+    if (! (_displayfunction & LCD_8BITMODE)) {
+        // this is according to the hitachi HD44780 datasheet
+        // figure 24, pg 46
+
+        // we start in 8bit mode, try to set 4 bit mode
+        write4bits(0x03);
+        wait_us(4500); // wait min 4.1ms
+
+        // second try
+        write4bits(0x03);
+        wait_us(4500); // wait min 4.1ms
+
+        // third go!
+        write4bits(0x03);
+        wait_us(150);
+
+        // finally, set to 8-bit interface
+        write4bits(0x02);
+    } else {
+        // this is according to the hitachi HD44780 datasheet
+        // page 45 figure 23
+
+        // Send function set command sequence
+        command(LCD_FUNCTIONSET | _displayfunction);
+        wait_us(4500);  // wait more than 4.1ms
+
+        // second try
+        command(LCD_FUNCTIONSET | _displayfunction);
+        wait_us(150);
+
+        // third go
+        command(LCD_FUNCTIONSET | _displayfunction);
+    }
+
+    // finally, set # lines, font size, etc.
+    command(LCD_FUNCTIONSET | _displayfunction);
+
+    // turn the display on with no cursor or blinking default
+    _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
+    display();
+
+    // clear it off
+    clear();
+
+    // Initialize to default text direction (for romance languages)
+    _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
+    // set the entry mode
+    command(LCD_ENTRYMODESET | _displaymode);
+
+}
+
+// write either command or data, with automatic 4/8-bit selection
+void Adafruit_I2C_LCD::send(uint8_t value, uint8_t mode)
+{
+    _digitalWrite(_rs_pin, mode);
+
+    // if there is a RW pin indicated, set it low to Write
+    if (_rw_pin != 255) {
+        _digitalWrite(_rw_pin, LOW);
+    }
+
+    if (_displayfunction & LCD_8BITMODE) {
+        write8bits(value);
+    } else {
+        write4bits(value>>4);
+        write4bits(value);
+    }
+}
+
+void Adafruit_I2C_LCD::pulseEnable(void)
+{
+    _digitalWrite(_enable_pin, LOW);
+    wait_us(1);
+    _digitalWrite(_enable_pin, HIGH);
+    wait_us(1);    // enable pulse must be >450ns
+    _digitalWrite(_enable_pin, LOW);
+    wait_us(100);   // commands need > 37us to settle
+}
+
+void Adafruit_I2C_LCD::write4bits(uint8_t value)
+{
+    //if (_i2cAddr != 255) {
+        uint16_t out = 0;
+
+        out = _i2c->readGPIOAB();
+
+        // speed up for i2c since its sluggish
+        for (int i = 0; i < 4; i++) {
+            out &= ~(1 << _data_pins[i]);
+            out |= ((value >> i) & 0x1) << _data_pins[i];
+        }
+
+        // make sure enable is low
+        out &= ~(1 << _enable_pin);
+
+        _i2c->writeGPIOAB(out);
+
+        // pulse enable
+        wait_us(1);
+        out |= (1 << _enable_pin);
+        _i2c->writeGPIOAB(out);
+        wait_us(1);
+        out &= ~(1 << _enable_pin);
+        _i2c->writeGPIOAB(out);
+        wait_us(100);
+
+    //} else {
+        //for (int i = 0; i < 4; i++) {
+        //    _pinMode(_data_pins[i], OUTPUT);
+        //    _digitalWrite(_data_pins[i], (value >> i) & 0x01);
+        //}
+        //pulseEnable();
+    //}
+}
+
+void Adafruit_I2C_LCD::write8bits(uint8_t value)
+{
+    for (int i = 0; i < 8; i++) {
+        _pinMode(_data_pins[i], OUTPUT);
+        _digitalWrite(_data_pins[i], (value >> i) & 0x01);
+    }
+
+    pulseEnable();
+}
+
+uint8_t Adafruit_I2C_LCD::readButtons(void)
+{
+    uint8_t reply = 0x1F;
+
+    for (uint8_t i=0; i<5; i++) {
+        reply &= ~((_i2c->digitalRead(_button_pins[i])) << i);
+    }
+    return reply;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_I2C_LCD.h	Mon Nov 19 09:44:37 2018 +0000
@@ -0,0 +1,130 @@
+/***************************************************
+  This is a library for the Adafruit RGB 16x2 LCD Shield
+  Pick one up at the Adafruit shop!
+  ---------> http://http://www.adafruit.com/products/714
+
+  The shield uses I2C to communicate, 2 pins are required to
+  interface
+  Adafruit invests time and resources providing this open source code,
+  please support Adafruit and open-source hardware by purchasing
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.
+  BSD license, all text above must be included in any redistribution
+ ****************************************************/
+
+#ifndef ADAFRUIT_I2C_LCD_H
+#define ADAFRUIT_I2C_LCD_H
+
+#include "Adafruit_MCP23017.h"
+
+// commands
+#define LCD_CLEARDISPLAY 0x01
+#define LCD_RETURNHOME 0x02
+#define LCD_ENTRYMODESET 0x04
+#define LCD_DISPLAYCONTROL 0x08
+#define LCD_CURSORSHIFT 0x10
+#define LCD_FUNCTIONSET 0x20
+#define LCD_SETCGRAMADDR 0x40
+#define LCD_SETDDRAMADDR 0x80
+
+// flags for display entry mode
+#define LCD_ENTRYRIGHT 0x00
+#define LCD_ENTRYLEFT 0x02
+#define LCD_ENTRYSHIFTINCREMENT 0x01
+#define LCD_ENTRYSHIFTDECREMENT 0x00
+
+// flags for display on/off control
+#define LCD_DISPLAYON 0x04
+#define LCD_DISPLAYOFF 0x00
+#define LCD_CURSORON 0x02
+#define LCD_CURSOROFF 0x00
+#define LCD_BLINKON 0x01
+#define LCD_BLINKOFF 0x00
+
+// flags for display/cursor shift
+#define LCD_DISPLAYMOVE 0x08
+#define LCD_CURSORMOVE 0x00
+#define LCD_MOVERIGHT 0x04
+#define LCD_MOVELEFT 0x00
+
+// flags for function set
+#define LCD_8BITMODE 0x10
+#define LCD_4BITMODE 0x00
+#define LCD_2LINE 0x08
+#define LCD_1LINE 0x00
+#define LCD_5x10DOTS 0x04
+#define LCD_5x8DOTS 0x00
+
+#define BUTTON_UP 0x08
+#define BUTTON_DOWN 0x04
+#define BUTTON_LEFT 0x10
+#define BUTTON_RIGHT 0x02
+#define BUTTON_SELECT 0x01
+
+#define HIGH true
+#define LOW false
+
+#include "mbed.h"
+
+class Adafruit_I2C_LCD
+{
+public:
+    Adafruit_I2C_LCD(I2C *master, uint8_t cols, uint8_t lines, uint8_t dotsize = LCD_5x8DOTS);
+    ~Adafruit_I2C_LCD();
+
+    void clear();
+    void home();
+
+    void noDisplay();
+    void display();
+    void noBlink();
+    void blink();
+    void noCursor();
+    void cursor();
+    void scrollDisplayLeft();
+    void scrollDisplayRight();
+    void leftToRight();
+    void rightToLeft();
+    void autoscroll();
+    void noAutoscroll();
+
+    // only if using backpack
+    void setBacklight(uint8_t status);
+
+    void createChar(uint8_t, uint8_t[]);
+    void setCursor(uint8_t, uint8_t);
+    void write(uint8_t);
+    void print(char *, size_t);
+    void command(uint8_t);
+    uint8_t readButtons();
+
+private:
+	void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
+	
+    void send(uint8_t, uint8_t);
+    void write4bits(uint8_t);
+    void write8bits(uint8_t);
+    void pulseEnable();
+    void _digitalWrite(uint8_t, uint8_t);
+    void _pinMode(uint8_t, uint8_t);
+
+    uint8_t _rs_pin; // LOW: command.  HIGH: character.
+    uint8_t _rw_pin; // LOW: write to LCD.  HIGH: read from LCD.
+    uint8_t _enable_pin; // activated by a HIGH pulse.
+    uint8_t _data_pins[8];
+    uint8_t _button_pins[5];
+    uint8_t _displayfunction;
+    uint8_t _displaycontrol;
+    uint8_t _displaymode;
+
+    uint8_t _initialized;
+
+    uint8_t _numlines,_currline;
+
+    uint8_t _i2cAddr;
+    Adafruit_MCP23017 *_i2c;
+};
+
+#endif
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_MCP23017.cpp	Mon Nov 19 09:44:37 2018 +0000
@@ -0,0 +1,231 @@
+/***************************************************
+  This is a library for the MCP23017 i2c port expander
+
+  These displays use I2C to communicate, 2 pins are required to
+  interface
+  Adafruit invests time and resources providing this open source code,
+  please support Adafruit and open-source hardware by purchasing
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.
+  BSD license, all text above must be included in any redistribution
+ ****************************************************/
+
+#include "Adafruit_MCP23017.h"
+
+Adafruit_MCP23017::Adafruit_MCP23017(I2C *master)
+{
+    _master = master;
+
+
+    // set defaults!
+    
+    _buffer = new char[2]();
+    _buffer[0] = MCP23017_IODIRA;
+    _buffer[1] = 0xFF;
+    _master->write(MCP23017_ADDRESS, _buffer, 2);  // all inputs on port A
+    _buffer[0] = MCP23017_IODIRB;
+    _buffer[1] = 0xFF;
+    _master->write(MCP23017_ADDRESS, _buffer, 2);  // all inputs on port B
+    delete[] _buffer;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+void Adafruit_MCP23017::pinMode(uint8_t p, bool input_mode)
+{
+    uint8_t iodir;
+    uint8_t iodiraddr;
+
+    // only 16 bits!
+    if (p > 15){
+        error("mcp23017 : it is a pin number which is not defined.\r\n");
+        return;
+	}
+	
+    if (p < 8)
+        iodiraddr = MCP23017_IODIRA;
+    else {
+        iodiraddr = MCP23017_IODIRB;
+        p -= 8;
+    }
+
+    // read the current IODIR
+	_buffer = new char[1]();
+    _buffer[0] = iodiraddr;
+    _master->write(MCP23017_ADDRESS, _buffer, 1);
+    _buffer[0] = 0;
+    _master->read(MCP23017_ADDRESS, _buffer, 1);
+    iodir = _buffer[0];
+    delete[] _buffer;
+
+    // set the pin and direction
+    if (input_mode) {
+        iodir |= 1 << p;
+    } else {
+        iodir &= ~(1 << p);
+    }
+
+    // write the new IODIR
+    _buffer = new char[2]();
+    _buffer[0] = iodiraddr;
+    _buffer[1] = iodir;
+    _master->write(MCP23017_ADDRESS, _buffer, 2);
+    delete[] _buffer;
+}
+
+uint16_t Adafruit_MCP23017::readGPIOAB()
+{
+    uint16_t ba = 0;
+    uint8_t a;
+
+    // read the current GPIO output latches
+    _buffer = new char[1]();
+    _buffer[0] = MCP23017_GPIOA;
+    _master->write(MCP23017_ADDRESS, _buffer, 1);
+    delete[] _buffer;
+    
+    _buffer = new char[2]();
+    _master->read(MCP23017_ADDRESS, _buffer, 2);
+    a = _buffer[0];
+    ba = _buffer[1];
+    ba <<= 8;
+    ba |= a;
+    delete[] _buffer;
+
+    return ba;
+}
+
+void Adafruit_MCP23017::writeGPIOAB(uint16_t ba)
+{
+    _buffer = new char[3]();
+    _buffer[0] = MCP23017_GPIOA;
+    _buffer[1] = ba & 0xFF;
+    _buffer[2] = ba >> 8;
+    _master->write(MCP23017_ADDRESS, _buffer, 3);
+    delete[] _buffer;
+}
+
+void Adafruit_MCP23017::digitalWrite(uint8_t p, bool high)
+{
+    uint8_t gpio;
+    uint8_t gpioaddr, olataddr;
+
+    if (p > 15){
+        error("mcp23017 : it is a pin number which is not defined.\r\n");
+        return;
+	}
+
+    if (p < 8) {
+        olataddr = MCP23017_OLATA;
+        gpioaddr = MCP23017_GPIOA;
+    } else {
+        olataddr = MCP23017_OLATB;
+        gpioaddr = MCP23017_GPIOB;
+        p -= 8;
+    }
+
+    // read the current GPIO output latches
+    _buffer = new char[1]();
+    _buffer[0] = olataddr;
+    _master->write(MCP23017_ADDRESS,_buffer , 1);
+    delete[] _buffer;
+	
+	_buffer = new char[1]();
+    _master->read(MCP23017_ADDRESS, _buffer, 1);
+    gpio = _buffer[0];
+    delete[] _buffer;
+
+    // set the pin and direction
+    if (high) {
+        gpio |= 1 << p;
+    } else {
+        gpio &= ~(1 << p);
+    }
+
+    // write the new GPIO
+    _buffer = new char[2]();
+    _buffer[0] = gpioaddr;
+    _buffer[1] = gpio;
+    _master->write(MCP23017_ADDRESS, _buffer, 2);
+    delete[] _buffer;
+}
+
+void Adafruit_MCP23017::pullUp(uint8_t p, bool pullup_anable)
+{
+    uint8_t gppu;
+    uint8_t gppuaddr;
+
+    // only 16 bits!
+    if (p > 15){
+        error("mcp23017 : it is a pin number which is not defined.\r\n");
+        return;
+	}
+
+    if (p < 8)
+        gppuaddr = MCP23017_GPPUA;
+    else {
+        gppuaddr = MCP23017_GPPUB;
+        p -= 8;
+    }
+
+    // read the current pullup resistor set
+    _buffer = new char[1]();
+    _buffer[0] = gppuaddr;
+    _master->write(MCP23017_ADDRESS, _buffer, 1);
+	delete[] _buffer;
+	
+	_buffer = new char[1]();
+    _master->read(MCP23017_ADDRESS, _buffer, 1);
+    gppu = _buffer[0];
+    delete[] _buffer;
+
+    // set the pin and direction
+    if (pullup_anable) {
+        gppu |= 1 << p;
+    } else {
+        gppu &= ~(1 << p);
+    }
+
+    // write the new GPIO
+    _buffer = new char[2]();
+    _buffer[0] = gppuaddr;
+    _buffer[1] = gppu;
+    _master->write(MCP23017_ADDRESS, _buffer, 2);
+    delete[] _buffer;
+    
+}
+
+uint8_t Adafruit_MCP23017::digitalRead(uint8_t p)
+{
+    uint8_t gpioaddr;
+
+    // only 16 bits!
+    if (p > 15){
+        error("mcp23017 : it is a pin number which is not defined.\r\n");
+        return 0;
+	}
+	
+    if (p < 8)
+        gpioaddr = MCP23017_GPIOA;
+    else {
+        gpioaddr = MCP23017_GPIOB;
+        p -= 8;
+    }
+
+    // read the current GPIO
+    
+    _buffer = new char[1]();
+    _buffer[0] = gpioaddr;
+	_master->write(MCP23017_ADDRESS, _buffer, 1);
+    
+    _buffer[0] = 0;
+    
+	uint8_t gpio;
+  	_master->read(MCP23017_ADDRESS, _buffer, 1);
+    gpio = _buffer[0];
+    
+    delete[] _buffer;
+    return (gpio >> p) & 0x1;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_MCP23017.h	Mon Nov 19 09:44:37 2018 +0000
@@ -0,0 +1,71 @@
+/***************************************************
+  This is a library for the MCP23017 i2c port expander
+
+  These displays use I2C to communicate, 2 pins are required to
+  interface
+  Adafruit invests time and resources providing this open source code,
+  please support Adafruit and open-source hardware by purchasing
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.
+  BSD license, all text above must be included in any redistribution
+ ****************************************************/
+
+#ifndef _Adafruit_MCP23017_H_
+#define _Adafruit_MCP23017_H_
+
+#include "mbed.h"
+
+class Adafruit_MCP23017
+{
+public:
+    Adafruit_MCP23017(I2C *master);
+    ~Adafruit_MCP23017(){};
+
+    void pinMode(uint8_t p, bool input_mode);
+    void digitalWrite(uint8_t p, bool high);
+    void pullUp(uint8_t p, bool pullup_anable);
+    uint8_t digitalRead(uint8_t p);
+
+    void writeGPIOAB(uint16_t);
+    uint16_t readGPIOAB();
+
+private:
+    I2C *_master;
+    char *_buffer;
+};
+
+//#define MCP23017_ADDRESS 0x20
+#define MCP23017_ADDRESS 0x40
+
+#define INPUT 1
+#define OUTPUT 0
+
+// registers
+#define MCP23017_IODIRA 0x00
+#define MCP23017_IPOLA 0x02
+#define MCP23017_GPINTENA 0x04
+#define MCP23017_DEFVALA 0x06
+#define MCP23017_INTCONA 0x08
+#define MCP23017_IOCONA 0x0A
+#define MCP23017_GPPUA 0x0C
+#define MCP23017_INTFA 0x0E
+#define MCP23017_INTCAPA 0x10
+#define MCP23017_GPIOA 0x12
+#define MCP23017_OLATA 0x14
+
+
+#define MCP23017_IODIRB 0x01
+#define MCP23017_IPOLB 0x03
+#define MCP23017_GPINTENB 0x05
+#define MCP23017_DEFVALB 0x07
+#define MCP23017_INTCONB 0x09
+#define MCP23017_IOCONB 0x0B
+#define MCP23017_GPPUB 0x0D
+#define MCP23017_INTFB 0x0F
+#define MCP23017_INTCAPB 0x11
+#define MCP23017_GPIOB 0x13
+#define MCP23017_OLATB 0x15
+
+#endif
+