mcp23s17_drv.h

//
// mcp23s17_drv.h
//
//  Created on: 28.02.2016
//      Author: Andreas Terstegge
//
 
 
/*******************************************************
      MCP23S17 I/O Expander with Serial interface
 
 This is a driver for the MCP23S17 GPIO expander, which
 has 2 8-bit ports (A & B), and is accessed via the SPI
 interface.
 
 The two ports are accessed as one 16-bit port, using
 the following bit-numbering:
 
 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
 \_______GPIOB_________/ \_______GPIOA_________/
 MSB                 LSB MSB                 LSB
 
 29.01.2015  initial version
 
 (c) 2015 A. Terstegge
 
********************************************************/
#ifndef _MCP23S17_DRV_H_
#define _MCP23S17_DRV_H_
 
#include "gpio_interface.h"
#include "spi_interface.h"
 
class mcp23s17_drv : public gpio_interface {
 
  public:
    // User interface
    // The 2. constructor parameter is the SPI hardware
    // address of the device (0...7);
    mcp23s17_drv(spi_interface & hw, uint8_t spi_addr);
 
    // Basic GPIO handling
    void gpioMode (uint16_t mode);
    bool gpioRead ();
    void gpioWrite(bool value);
 
    // Interrupt handling
    void attachInterrupt (void (*)(uint16_t gpio), uint16_t mode);
    void detachInterrupt ();
    void enableInterrupt ();
    void disableInterrupt();
    void handleInterrupt();
 
    // Methods to read/write the entire port
    // Only bits with '1' in the mask are processed
    uint16_t digitalReadPort (uint16_t mask = 0xffff);
    void     digitalWritePort(uint16_t value, uint16_t mask = 0xffff);
 
    virtual ~mcp23s17_drv() { }
 
  private:
    uint8_t _port;
    uint8_t _pin;
 
    // SPI data
    spi_interface & _spi;
    uint8_t         _spi_addr;  // 0...7
 
    // register values
    uint16_t _iodir;
    uint16_t _gppu;
    uint16_t _olat;
    uint16_t _gpinten;
    uint16_t _defval;
    uint16_t _intcon;
 
    // interrupt handler functions
    void   (*intHandler[2][8])(uint16_t gpio);
    uint16_t intMode[2][8];
 
    // Hardware interface
    uint16_t readRegister (uint8_t reg);
    void     writeRegister(uint8_t reg, uint16_t value);
 
};
 
#endif // _MCP23S17_DRV_H_