MCP23017.h

00001 /*  MCP23017 library for Arduino
00002     Copyright (C) 2009 David Pye    <davidmpye@gmail.com
00003     Modified for use on the MBED ARM platform
00004 
00005     This program is free software: you can redistribute it and/or modify
00006     it under the terms of the GNU General Public License as published by
00007     the Free Software Foundation, either version 3 of the License, or
00008     (at your option) any later version.
00009 
00010     This program is distributed in the hope that it will be useful,
00011     but WITHOUT ANY WARRANTY; without even the implied warranty of
00012     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013     GNU General Public License for more details.
00014 
00015     You should have received a copy of the GNU General Public License
00016     along with this program.  If not, see <http://www.gnu.org/licenses/>.
00017 */
00018 
00019 #ifndef     MBED_MCP23017_H
00020 #define     MBED_MCP23017_H
00021 
00022 #include    "mbed.h"
00023 
00024 //
00025 // Register defines from data sheet - we set IOCON.BANK to 0
00026 // as it is easier to manage the registers sequentially.
00027 //
00028 #define     IODIR       0x00
00029 #define     IPOL        0x02
00030 #define     GPINTEN     0x04
00031 #define     DEFVAL      0x06
00032 #define     INTCON      0x08
00033 #define     IOCON       0x0A
00034 #define     GPPU        0x0C
00035 #define     INTF        0x0E
00036 #define     INTCAP      0x10
00037 #define     GPIO        0x12
00038 #define     OLAT        0x14
00039 
00040 #define     I2C_BASE_ADDRESS    0x40
00041 
00042 #define     DIR_OUTPUT      0
00043 #define     DIR_INPUT       1
00044 
00045 /** MCP23017 class
00046  *
00047  * Allow access to an I2C connected MCP23017 16-bit I/O extender chip
00048  * Example:
00049  * @code
00050  *      MCP23017     *par_port; 
00051  * @endcode
00052  *
00053  */
00054 class MCP23017 {
00055 public:
00056     /** Constructor for the MCP23017 connected to specified I2C pins at a specific address
00057      *
00058      * 16-bit I/O expander with I2C interface
00059      *
00060      * @param   sda         I2C data pin
00061      * @param   scl         I2C clock pin
00062      * @param   i2cAddress  I2C address
00063      */
00064     MCP23017(PinName sda, PinName scl, int i2cAddress);
00065 
00066     /** Reset MCP23017 device to its power-on state
00067      */    
00068     void reset(void);
00069 
00070     /** Write a 0/1 value to an output bit
00071      *
00072      * @param   value         0 or 1
00073      * @param   bit_number    bit number range 0 --> 15
00074      */   
00075     void write_bit(int value, int bit_number);
00076       
00077     /** Write a masked 16-bit value to the device
00078      *
00079      * @param   data    16-bit data value
00080      * @param   mask    16-bit mask value
00081      */       
00082     void write_mask(unsigned short data, unsigned short mask);
00083 
00084     /** Read a 0/1 value from an input bit
00085      *
00086      * @param   bit_number    bit number range 0 --> 15
00087      * @return                0/1 value read
00088      */       
00089     int  read_bit(int bit_number);
00090     
00091     /** Read a 16-bit value from the device and apply mask
00092      *
00093      * @param   mask    16-bit mask value
00094      * @return          16-bit data with mask applied
00095      */     
00096     int  read_mask(unsigned short mask);
00097 
00098     /** Configure an MCP23017 device
00099      *
00100      * @param   dir_config         data direction value (1 = input, 0 = output)
00101      * @param   pullup_config      100k pullup value (1 = enabled, 0 = disabled)
00102      * @param   polarity_config    polarity value (1 = flip, 0 = normal)
00103      */           
00104     void config(unsigned short dir_config, unsigned short pullup_config, unsigned short polarity_config);
00105 
00106     void writeRegister(int regAddress, unsigned char  val);
00107     void writeRegister(int regAddress, unsigned short val);
00108     int  readRegister(int regAddress);
00109 
00110 /*----------------------------------------------------------------------------- 
00111  * pinmode
00112  * Set units to sequential, bank0 mode
00113  */  
00114     void pinMode(int pin, int mode); 
00115     void digitalWrite(int pin, int val);
00116     int  digitalRead(int pin);
00117 
00118 // These provide a more advanced mapping of the chip functionality
00119 // See the data sheet for more information on what they do
00120 
00121 //Returns a word with the current pin states (ie contents of the GPIO register)
00122     unsigned short digitalWordRead();
00123 // Allows you to write a word to the GPIO register
00124     void digitalWordWrite(unsigned short w);
00125 // Sets up the polarity mask that the MCP23017 supports
00126 // if set to 1, it will flip the actual pin value.
00127     void inputPolarityMask(unsigned short mask);
00128 //Sets which pins are inputs or outputs (1 = input, 0 = output) NB Opposite to arduino's
00129 //definition for these
00130     void inputOutputMask(unsigned short mask);
00131 // Allows enabling of the internal 100k pullup resisters (1 = enabled, 0 = disabled)
00132     void internalPullupMask(unsigned short mask);
00133     int read(void);
00134     void write(int data);
00135 
00136 protected:
00137     I2C     _i2c;
00138     int     MCP23017_i2cAddress;                        // physical I2C address
00139     unsigned short   shadow_GPIO, shadow_IODIR, shadow_GPPU, shadow_IPOL;     // Cached copies of the register values
00140     
00141 };
00142 
00143 #endif