MCP23S17.h

00001 /* MCP23S17 - drive the Microchip MCP23S17 16-bit Port Extender using SPI
00002 * Copyright (c) 2010 Romilly Cocking
00003 * Released under the MIT License: http://mbed.org/license/mit
00004 *
00005 * version 0.4
00006 */
00007 #include "mbed.h"
00008 
00009 #ifndef  MCP23S17_H
00010 #define  MCP23S17_H
00011 
00012 #define INTERRUPT_POLARITY_BIT 0x02
00013 #define INTERRUPT_MIRROR_BIT   0x40
00014 
00015 // all register addresses assume IOCON.BANK = 0 (POR default)
00016 
00017 #define IODIRA   0x00
00018 #define GPINTENA 0x04
00019 #define DEFVALA  0x06
00020 #define INTCONA  0x08
00021 #define IOCON    0x0A
00022 #define GPPUA    0x0C
00023 #define GPIOA    0x12
00024 #define OLATA    0x14
00025 
00026 // Control settings
00027 
00028 #define IOCON_BANK  0x80 // Banked registers
00029 #define IOCON_BYTE_MODE 0x20 // Disables sequential operation. If bank = 0, operations toggle between A and B registers
00030 #define IOCON_HAEN  0x08 // Hardware address enable
00031 
00032 enum Polarity { ACTIVE_LOW , ACTIVE_HIGH };
00033 enum Port { PORT_A, PORT_B };
00034 
00035 class MCP23S17 {
00036 public:
00037     MCP23S17(SPI& spi, PinName ncs, char writeOpcode);
00038     void direction(Port port, char direction);
00039     void configurePullUps(Port port, char offOrOn);
00040     void interruptEnable(Port port, char interruptsEnabledMask);
00041     void interruptPolarity(Polarity polarity);
00042     void mirrorInterrupts(bool mirror);
00043     void defaultValue(Port port, char valuesToCompare);
00044     void interruptControl(Port port, char interruptContolBits);
00045     char read(Port port);
00046     void write(Port port, char byte);
00047 protected:
00048     SPI& _spi;
00049     DigitalOut _ncs;
00050     void _init();
00051     void _write(Port port, char address, char data);
00052     void _write(char address, char data);
00053     char _read(Port port, char address);
00054     char _read(char address);
00055     char _readOpcode;
00056     char _writeOpcode;
00057 };
00058 
00059 #endif