MCP23008.h

00001 /*  MCP23008 library for Arduino
00002     Copyright (C) 2013 Stefan Jaensch, based on MCP23017 from 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_MCP23008_H
00020 #define     MBED_MCP23008_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        0x01
00030 #define     GPINTEN     0x02
00031 #define     DEFVAL      0x03
00032 #define     INTCON      0x04
00033 #define     IOCON       0x05
00034 #define     GPPU        0x06
00035 #define     INTF        0x07
00036 #define     INTCAP      0x08
00037 #define     GPIO        0x09
00038 #define     OLAT        0x0A
00039 
00040 #define     I2C_BASE_ADDRESS    0x40
00041 
00042 #define     DIR_OUTPUT      0
00043 #define     DIR_INPUT       1
00044 
00045 
00046 #define MCP23008_GP0    ( 0x01 )
00047 #define MCP23008_GP1    ( 0x02 )
00048 #define MCP23008_GP2    ( 0x04 )
00049 #define MCP23008_GP3    ( 0x08 )
00050 #define MCP23008_GP4    ( 0x10 )
00051 #define MCP23008_GP5    ( 0x20 )
00052 #define MCP23008_GP6    ( 0x40 )
00053 #define MCP23008_GP7    ( 0x80 )
00054 
00055 
00056 /** MCP23008 class
00057  *
00058  * Allow access to an I2C connected MCP23008 8-bit I/O extender chip
00059  * Example:
00060  * @code
00061  *      MCP23008     *par_port; 
00062         ...
00063         par_port = new MCP23008( p9, p10, I2C_ADD);
00064         par_port->config(0xF0,0,0); 
00065  * @endcode
00066  *
00067  */
00068 class MCP23008 {
00069 public:
00070     /** Constructor for the MCP23008 connected to specified I2C pins at a specific address
00071      *
00072      * 8-bit I/O expander with I2C interface
00073      *
00074      * @param   sda         I2C data pin
00075      * @param   scl         I2C clock pin
00076      * @param   i2cAddress  I2C address
00077      */
00078     MCP23008(PinName sda, PinName scl, int i2cAddress);
00079 
00080     /** Reset MCP23008 device to its power-on state
00081      */    
00082     void reset(void);
00083 
00084     /** Configure an MCP23008 device
00085      *
00086      * @param   dir_config         data direction value (1 = input, 0 = output)
00087      * @param   pullup_config      100k pullup value (1 = enabled, 0 = disabled)
00088      * @param   polarity_config    polarity value (1 = flip, 0 = normal)
00089      */           
00090     void config(unsigned char dir_config, unsigned char pullup_config,  unsigned char polarity_config);
00091       
00092     /** Write a masked 16-bit value to the device
00093      *
00094      * @param   data    8-bit data value
00095      * @param   mask    8-bit mask value
00096      */       
00097     void write_mask(unsigned char data, unsigned char mask);
00098     
00099     /** Read a 8-bit value from the device and apply mask
00100      *
00101      * @param   mask    8-bit mask value
00102      * @return          8-bit data with mask applied
00103      */     
00104     int  read_mask(unsigned char mask);
00105 
00106     /** Write a 0/1 value to an output bit
00107      *
00108      * @param   value         0 or 1
00109      * @param   bit_number    bit number range 0 --> 7
00110      */   
00111     void write_bit(int value, int bit_number);
00112 
00113     /** Read a 0/1 value from an input bit
00114      *
00115      * @param   bit_number    bit number range 0 --> 7
00116      * @return                0/1 value read
00117      */       
00118     int  read_bit(int bit_number);
00119     
00120 
00121     
00122 
00123 protected:
00124     void writeRegister(int regAddress, unsigned char data);
00125     unsigned char  readRegister(int regAddress);
00126     
00127     
00128     I2C     _i2c;
00129     int     MCP23008_i2cAddress;                        // physical I2C address
00130     unsigned char   shadow_GPIO, shadow_IODIR, shadow_GPPU, shadow_IPOL;     // Cached copies of the register values    
00131 };
00132 
00133 #endif