jim herd / MCP23017

Basic library of routines to interface to a Microchip MCP23017 16-bit I/O expander using an I2C interface.

Dependents:   Assignment_2_herpe Final_V1 ass2 ass2 ... more

MCP23017.h@12:6d9d2b277f26, 2010-11-29 (annotated)

Committer:
jimherd
Date:
Mon Nov 29 12:41:09 2010 +0000
Revision:
12:6d9d2b277f26
Parent:
11:8726c7be6d72
Child:
13:d57de266cf19

        

        
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/*  MCP23017 library for Arduino





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    Copyright (C) 2009 David Pye    <davidmpye@gmail.com





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    Modified for use on the MBED ARM platform





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    This program is free software: you can redistribute it and/or modify





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    it under the terms of the GNU General Public License as published by





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    the Free Software Foundation, either version 3 of the License, or





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    (at your option) any later version.





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    This program is distributed in the hope that it will be useful,





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    but WITHOUT ANY WARRANTY; without even the implied warranty of





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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the





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    GNU General Public License for more details.





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    You should have received a copy of the GNU General Public License





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    along with this program.  If not, see <http://www.gnu.org/licenses/>.





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*/





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#ifndef     MBED_MCP23017_H





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#define     MBED_MCP23017_H





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#include    "mbed.h"





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//





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// Register defines from data sheet - we set IOCON.BANK to 0





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// as it is easier to manage the registers sequentially.





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//





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#define     IODIR       0x00





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#define     IPOL        0x02





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#define     GPINTEN     0x04





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#define     DEFVAL      0x06





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#define     INTCON      0x08





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#define     IOCON       0x0A





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#define     GPPU        0x0C





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#define     INTF        0x0E





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#define     INTCAP      0x10





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#define     GPIO        0x12





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#define     OLAT        0x14





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#define     I2C_BASE_ADDRESS    0x40





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#define     DIR_OUTPUT      0





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#define     DIR_INPUT       1





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/** MCP23017 class





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 *





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 */





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class MCP23017 {





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public:





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    /** Constructor for the MCP23017 connected to specified I2C pins at a specific address





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     *





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     * 16-bit I/O expander with I2C interface





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     *





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     * @param   sda         I2C data pin





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     * @param   scl         I2C clock pin





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     * @param   i2cAddress  I2C address





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     */





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    MCP23017(PinName sda, PinName scl, int i2cAddress);





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    /** Reset MCP23017 device to its power-on state





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     */    





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    void reset(void);





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    /** Write a 0/1 value to an output bit





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     *





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     * @param   value         0 or 1





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     * @param   bit_number    bit number range 0 --> 15





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     */   





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    void write_bit(int value, int bit_number);





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    /** Write a masked 16-bit value to the device





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     *





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     * @param   data    16-bit data value





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     * @param   mask    16-bit mask value





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     */       





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    void write_mask(unsigned short data, unsigned short mask);





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    /** Read a 0/1 value from an input bit





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     *





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     * @param   bit_number    bit number range 0 --> 15





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     * @return                0/1 value read





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     */       





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    int  read_bit(int bit_number);





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    /** Read a 16-bit value from the device and apply mask





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     *





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     * @param   mask    16-bit mask value





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     * @return          16-bit data with mask applied





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     */     





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    int  read_mask(unsigned short mask);





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    /** Configure an MCP23017 device





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     *





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     * @param   dir_config         data direction value (1 = input, 0 = output)





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     * @param   pullup_config      100k pullup value (1 = enabled, 0 = disabled)





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     * @param   polarity_config    polarity value (1 = flip, 0 = normal)





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     */           





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    void config(unsigned short dir_config, unsigned short pullup_config, unsigned short polarity_config);





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    void writeRegister(int regAddress, unsigned char  val);





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    void writeRegister(int regAddress, unsigned short val);





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    int  readRegister(int regAddress);





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/*----------------------------------------------------------------------------- 





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 * pinmode





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 * Set units to sequential, bank0 mode





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 */  





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    void pinMode(int pin, int mode); 





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    void digitalWrite(int pin, int val);





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    int  digitalRead(int pin);





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// These provide a more advanced mapping of the chip functionality





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// See the data sheet for more information on what they do





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//Returns a word with the current pin states (ie contents of the GPIO register)





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    unsigned short digitalWordRead();





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// Allows you to write a word to the GPIO register





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    void digitalWordWrite(unsigned short w);





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// Sets up the polarity mask that the MCP23017 supports





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// if set to 1, it will flip the actual pin value.





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    void inputPolarityMask(unsigned short mask);





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//Sets which pins are inputs or outputs (1 = input, 0 = output) NB Opposite to arduino's





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//definition for these





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    void inputOutputMask(unsigned short mask);





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// Allows enabling of the internal 100k pullup resisters (1 = enabled, 0 = disabled)





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    void internalPullupMask(unsigned short mask);





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    int read(void);





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    void write(int data);





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protected:





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    I2C     _i2c;





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    int     MCP23017_i2cAddress;                        // physical I2C address





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    unsigned short   shadow_GPIO, shadow_IODIR, shadow_GPPU, shadow_IPOL;     // Cached copies of the register values





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};





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#endif