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 * Changed by Jacco van Splunter:
00005 * The _read and _write functions are moved from protected -> public
00006 *
00007 * Released under the MIT License: http://mbed.org/license/mit
00008 *
00009 * version 0.2 Initial Release
00010 * version 0.3 Cleaned up
00011 * version 0.4 Fixed problem with _read method
00012 * version 0.5 Added support for 'Banked' access to registers
00013 */
00014 #include "mbed.h"
00015 
00016 #ifndef  MCP23017_H
00017 #define  MCP23017_H
00018 
00019 // All register addresses assume IOCON.BANK = 0 (POR default)
00020 #define IODIRA   0x00
00021 #define IODIRB   0x01
00022 #define IPOLA    0x02
00023 #define IPOLB    0x03
00024 #define GPINTENA 0x04
00025 #define GPINTENB 0x05
00026 #define DEFVALA  0x06
00027 #define DEFVALB  0x07
00028 #define INTCONA  0x08
00029 #define INTCONB  0x09
00030 #define IOCONA   0x0A
00031 #define IOCONB   0x0B
00032 #define GPPUA    0x0C
00033 #define GPPUB    0x0D
00034 #define INTFA    0x0E
00035 #define INTFB    0x0F
00036 #define INTCAPA  0x10
00037 #define INTCAPB  0x11
00038 #define GPIOA    0x12
00039 #define GPIOB    0x13
00040 #define OLATA    0x14
00041 #define OLATB    0x15
00042 
00043 // The following register addresses assume IOCON.BANK = 1 
00044 #define IODIRA_BNK   0x00
00045 #define IPOLA_BNK    0x01
00046 #define GPINTENA_BNK 0x02
00047 #define DEFVALA_BNK  0x03
00048 #define INTCONA_BNK  0x04
00049 #define IOCONA_BNK   0x05
00050 #define GPPUA_BNK    0x06
00051 #define INTFA_BNK    0x07
00052 #define INTCAPA_BNK  0x08
00053 #define GPIOA_BNK    0x09
00054 #define OLATA_BNK    0x0A
00055 
00056 #define IODIRB_BNK   0x10
00057 #define IPOLB_BNK    0x11
00058 #define GPINTENB_BNK 0x12
00059 #define DEFVALB_BNK  0x13
00060 #define INTCONB_BNK  0x14
00061 #define IOCONB_BNK   0x15
00062 #define GPPUB_BNK    0x16
00063 #define INTFB_BNK    0x17
00064 #define INTCAPB_BNK  0x18
00065 #define GPIOB_BNK    0x19
00066 #define OLATB_BNK    0x1A
00067 
00068 // This array allows structured access to Port_A and Port_B registers for both bankModes
00069 const int IODIR_AB[2][2]   = {{IODIRA, IODIRB},     {IODIRA_BNK, IODIRB_BNK}};
00070 const int IPOL_AB[2][2]    = {{IPOLA, IPOLB},       {IPOLA_BNK, IPOLB_BNK}};
00071 const int GPINTEN_AB[2][2] = {{GPINTENA, GPINTENB}, {GPINTENA_BNK, GPINTENB_BNK}};
00072 const int DEFVAL_AB[2][2]  = {{DEFVALA, DEFVALB},   {DEFVALA_BNK, DEFVALB_BNK}};
00073 const int INTCON_AB[2][2]  = {{INTCONA, INTCONB},   {INTCONA_BNK, INTCONB_BNK}};
00074 const int IOCON_AB[2][2]   = {{IOCONA, IOCONB},     {IOCONA_BNK, IOCONB_BNK}};
00075 const int GPPU_AB[2][2]    = {{GPPUA, GPPUB},       {GPPUA_BNK, GPPUB_BNK}};
00076 const int INTF_AB[2][2]    = {{INTFA, INTFB},       {INTFA_BNK, INTFB_BNK}};
00077 const int INTCAP_AB[2][2]  = {{INTCAPA, INTCAPB},   {INTCAPA_BNK, INTCAPB_BNK}};
00078 const int GPIO_AB[2][2]    = {{GPIOA, GPIOB},       {GPIOA_BNK, GPIOB_BNK}};
00079 const int OLAT_AB[2][2]    = {{OLATA, OLATB},       {OLATA_BNK, OLATB_BNK}};
00080 
00081 
00082 // Control settings
00083 #define IOCON_BANK      0x80 // Banked registers for Port A and B
00084 #define IOCON_BYTE_MODE 0x20 // Disables sequential operation, Address Ptr does not increment
00085                              //   If Disabled and Bank = 0, operations toggle between Port A and B registers
00086                              //   If Disabled and Bank = 1, operations do not increment registeraddress                             
00087 #define IOCON_HAEN      0x08 // Hardware address enable
00088 
00089 #define INTERRUPT_POLARITY_BIT 0x02
00090 #define INTERRUPT_MIRROR_BIT   0x40
00091 
00092 #define PORT_DIR_OUT   0x00
00093 #define PORT_DIR_IN    0xFF
00094 
00095 enum Polarity { ACTIVE_LOW , ACTIVE_HIGH };
00096 enum Port { PORT_A=0, PORT_B=1 };
00097 enum Bank { NOT_BNK=0, BNK=1 };
00098 
00099 class MCP23017 {
00100 public:
00101     /** Create an MCP23017 object connected to the specified I2C object and using the specified deviceAddress
00102     *
00103     * @param I2C &i2c the I2C port to connect to 
00104     * @param char deviceAddress the address of the MCP23017
00105     */
00106     MCP23017(I2C &i2c, char deviceAddress);
00107 
00108     /** Set I/O direction of specified MCP23017 Port
00109     *
00110     * @param Port Port address (Port_A or Port_B)
00111     * @param char direction pin direction (0 = output, 1 = input)
00112     */
00113     void direction(Port port, char direction);
00114 
00115     /** Set Pull-Up Resistors on specified MCP23017 Port
00116     *
00117     * @param Port Port address (Port_A or Port_B)
00118     * @param char offOrOn per pin (0 = off, 1 = on)
00119     */    
00120     void configurePullUps(Port port, char offOrOn);
00121 
00122     void configureBanked(Bank bankmode);  
00123     void interruptEnable(Port port, char interruptsEnabledMask);
00124     void interruptPolarity(Polarity polarity);
00125     void mirrorInterrupts(bool mirror);
00126     void defaultValue(Port port, char valuesToCompare);
00127     void interruptControl(Port port, char interruptControlBits);
00128 
00129     /** Read from specified MCP23017 Port
00130     *
00131     * @param Port Port address (Port_A or Port_B)
00132     * @returns data from Port 
00133     */
00134     char read(Port port);
00135     
00136     /** Write to specified MCP23017 Port
00137     *
00138     * @param Port Port address (Port_A or Port_B)
00139     * @param char byte data to write
00140     */    
00141     void write(Port port, char byte);
00142     
00143     /** Write to specified MCP23017 register
00144     *
00145     * @param char address the internal registeraddress of the MCP23017
00146     */
00147     void _write(char address, char byte);
00148 
00149     /** Read from specified MCP23017 register
00150     *
00151     * @param char address the internal registeraddress of the MCP23017
00152     * @returns data from register 
00153     */
00154     char _read(char address);
00155 
00156 protected:
00157     I2C &_i2c;
00158     char _readOpcode;
00159     char _writeOpcode;
00160     Bank _bankMode; 
00161     
00162     /** Init MCP23017
00163     *
00164     * @param
00165     * @returns 
00166     */    
00167     void _init();
00168 };
00169 
00170 #endif