MCP23017.h

00001 /* MCP23017 - drive the Microchip MCP23017 16-bit Port Extender using I2C
00002 * Copyright (c) 2010 Wim Huiskamp, Romilly Cocking (original version for SPI)
00003 *
00004 * Released under the MIT License: http://mbed.org/license/mit
00005 *
00006 * version 0.2 Initial Release
00007 * version 0.3 Cleaned up
00008 * version 0.4 Fixed problem with _read method
00009 * version 0.5 Added support for 'Banked' access to registers
00010 */
00011 #include "mbed.h"
00012 
00013 #ifndef  MCP23017_H
00014 #define  MCP23017_H
00015 
00016 // All register addresses assume IOCON.BANK = 0 (POR default)
00017 #define IODIRA   0x00
00018 #define IODIRB   0x01
00019 #define IPOLA    0x02
00020 #define IPOLB    0x03
00021 #define GPINTENA 0x04
00022 #define GPINTENB 0x05
00023 #define DEFVALA  0x06
00024 #define DEFVALB  0x07
00025 #define INTCONA  0x08
00026 #define INTCONB  0x09
00027 #define IOCONA   0x0A
00028 #define IOCONB   0x0B
00029 #define GPPUA    0x0C
00030 #define GPPUB    0x0D
00031 #define INTFA    0x0E
00032 #define INTFB    0x0F
00033 #define INTCAPA  0x10
00034 #define INTCAPB  0x11
00035 #define GPIOA    0x12
00036 #define GPIOB    0x13
00037 #define OLATA    0x14
00038 #define OLATB    0x15
00039 
00040 // The following register addresses assume IOCON.BANK = 1 
00041 #define IODIRA_BNK   0x00
00042 #define IPOLA_BNK    0x01
00043 #define GPINTENA_BNK 0x02
00044 #define DEFVALA_BNK  0x03
00045 #define INTCONA_BNK  0x04
00046 #define IOCONA_BNK   0x05
00047 #define GPPUA_BNK    0x06
00048 #define INTFA_BNK    0x07
00049 #define INTCAPA_BNK  0x08
00050 #define GPIOA_BNK    0x09
00051 #define OLATA_BNK    0x0A
00052 
00053 #define IODIRB_BNK   0x10
00054 #define IPOLB_BNK    0x11
00055 #define GPINTENB_BNK 0x12
00056 #define DEFVALB_BNK  0x13
00057 #define INTCONB_BNK  0x14
00058 #define IOCONB_BNK   0x15
00059 #define GPPUB_BNK    0x16
00060 #define INTFB_BNK    0x17
00061 #define INTCAPB_BNK  0x18
00062 #define GPIOB_BNK    0x19
00063 #define OLATB_BNK    0x1A
00064 
00065 // This array allows structured access to Port_A and Port_B registers for both bankModes
00066 const int IODIR_AB[2][2]   = {{IODIRA, IODIRB},     {IODIRA_BNK, IODIRB_BNK}};
00067 const int IPOL_AB[2][2]    = {{IPOLA, IPOLB},       {IPOLA_BNK, IPOLB_BNK}};
00068 const int GPINTEN_AB[2][2] = {{GPINTENA, GPINTENB}, {GPINTENA_BNK, GPINTENB_BNK}};
00069 const int DEFVAL_AB[2][2]  = {{DEFVALA, DEFVALB},   {DEFVALA_BNK, DEFVALB_BNK}};
00070 const int INTCON_AB[2][2]  = {{INTCONA, INTCONB},   {INTCONA_BNK, INTCONB_BNK}};
00071 const int IOCON_AB[2][2]   = {{IOCONA, IOCONB},     {IOCONA_BNK, IOCONB_BNK}};
00072 const int GPPU_AB[2][2]    = {{GPPUA, GPPUB},       {GPPUA_BNK, GPPUB_BNK}};
00073 const int INTF_AB[2][2]    = {{INTFA, INTFB},       {INTFA_BNK, INTFB_BNK}};
00074 const int INTCAP_AB[2][2]  = {{INTCAPA, INTCAPB},   {INTCAPA_BNK, INTCAPB_BNK}};
00075 const int GPIO_AB[2][2]    = {{GPIOA, GPIOB},       {GPIOA_BNK, GPIOB_BNK}};
00076 const int OLAT_AB[2][2]    = {{OLATA, OLATB},       {OLATA_BNK, OLATB_BNK}};
00077 
00078 
00079 // Control settings
00080 #define IOCON_BANK      0x80 // Banked registers for Port A and B
00081 #define IOCON_BYTE_MODE 0x20 // Disables sequential operation, Address Ptr does not increment
00082                              //   If Disabled and Bank = 0, operations toggle between Port A and B registers
00083                              //   If Disabled and Bank = 1, operations do not increment registeraddress                             
00084 #define IOCON_HAEN      0x08 // Hardware address enable
00085 
00086 #define INTERRUPT_POLARITY_BIT 0x02
00087 #define INTERRUPT_MIRROR_BIT   0x40
00088 
00089 #define PORT_DIR_OUT   0x00
00090 #define PORT_DIR_IN    0xFF
00091 
00092 enum Polarity { ACTIVE_LOW , ACTIVE_HIGH };
00093 enum Port { PORT_A=0, PORT_B=1 };
00094 enum Bank { NOT_BNK=0, BNK=1 };
00095 
00096 class MCP23017 {
00097 public:
00098     /** Create an MCP23017 object connected to the specified I2C object and using the specified deviceAddress
00099     *
00100     * @param I2C &i2c the I2C port to connect to 
00101     * @param char deviceAddress the address of the MCP23017
00102     */
00103     MCP23017(I2C &i2c, char deviceAddress);
00104 
00105     /** Set I/O direction of specified MCP23017 Port
00106     *
00107     * @param Port Port address (Port_A or Port_B)
00108     * @param char direction pin direction (0 = output, 1 = input)
00109     */
00110     void direction(Port port, char direction);
00111 
00112     /** Set Pull-Up Resistors on specified MCP23017 Port
00113     *
00114     * @param Port Port address (Port_A or Port_B)
00115     * @param char offOrOn per pin (0 = off, 1 = on)
00116     */    
00117     void configurePullUps(Port port, char offOrOn);
00118 
00119     void configureBanked(Bank bankmode);  
00120     void interruptEnable(Port port, char interruptsEnabledMask);
00121     void interruptPolarity(Polarity polarity);
00122     void mirrorInterrupts(bool mirror);
00123     void defaultValue(Port port, char valuesToCompare);
00124     void interruptControl(Port port, char interruptControlBits);
00125 
00126     /** Read from specified MCP23017 Port
00127     *
00128     * @param Port Port address (Port_A or Port_B)
00129     * @returns data from Port 
00130     */
00131     char read(Port port);
00132     
00133     /** Write to specified MCP23017 Port
00134     *
00135     * @param Port Port address (Port_A or Port_B)
00136     * @param char byte data to write
00137     */    
00138     void write(Port port, char byte);
00139 
00140 protected:
00141     I2C &_i2c;
00142     char _readOpcode;
00143     char _writeOpcode;
00144     Bank _bankMode; 
00145     
00146     /** Init MCP23017
00147     *
00148     * @param
00149     * @returns 
00150     */    
00151     void _init();
00152     
00153     /** Write to specified MCP23017 register
00154     *
00155     * @param char address the internal registeraddress of the MCP23017
00156     */
00157     void _write(char address, char byte);
00158 
00159     /** Read from specified MCP23017 register
00160     *
00161     * @param char address the internal registeraddress of the MCP23017
00162     * @returns data from register 
00163     */
00164     char _read(char address);
00165 };
00166 
00167 #endif