File content as of revision 3:0acab5201dd8:

/* mbed simplified access to Microchip MCP42xxx/MCP41xxx Digital Potentiometer devices (SPI)
 * Copyright (c) 2013-2013 ygarcia, MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
 * and associated documentation files (the "Software"), to deal in the Software without restriction, 
 * including without limitation the rights to use, copy, modify, merge, publish, distribute, 
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or 
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#if !defined(__MCP4xxxx_SPI_H__)
#define __MCP4xxxx_SPI_H__

#include <string>
#include <vector>

#include "Debug.h" // Include mbed header + debug primitives. See DebugLibrary

namespace MCP4xxxx_SPI {

    /** This class provides simplified SPI access to a Microchip MCP42xxx/MCP41xxx Digital Potentiometer device. V0.0.0.1
     *
     * Microchip MCP42xxx/MCP41xxx Serial EEPROM device reference: DS11195C
     *
     * Note that for SPI details, please visit http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus
     *
     * @remark This class was validated with Tektronix TDS2014 oscilloscope in 3.3V
     * @author Yann Garcia (Don't hesitate to contact me: garcia.yann@gmail.com)
     */
    class CMCP4xxxx_SPI { 
        /** Reference counter used to guarentee unicity of the instance of SPI class
         */
        static unsigned char SPIModuleRefCounter;
        
        /** ChipSelect (pin 1) see DS11195C-page 12 Clause 3.4 Chip Select (CS)
         */
        DigitalOut *_cs;
        
        /** Reset state indicator (pin 11), see DS11195C-page 21 Clause 5.5 Reset (RS) Pin Operation
         */
        DigitalOut *_reset;
        
        /** Shutdown state indicator (pin 12) see DS11195C-page 21 5.6 Shutdown (SHDN) Pin Operation
         */
        DigitalOut *_shdn;
        
        /** An unique instance of SPI class
         */
        SPI *_spiInstance;
     public:
        /** Authorized commands
         * See DS11195C-page 18
         */
        enum Commands {
            WriteToPot1, //<! Write to digital potentiometer #1
            WriteToPot2, //<! Write to digital potentiometer #2
            WriteToBoth, //<! Write to both digital potentiometers
            ShutdownPot1, //<! Shutdown digital potentiometer #1
            ShutdownPot2, //<! Shutdown digital potentiometer #2
            ShutdownBoth, //<! Shutdown both digital potentiometers
        };
   public:
        /** Constructor with Write Protect command pin wired.
         *
         * @param p_mosi: MBed pin for SDI
         * @param p_miso: MBed pin for SDO. Note that this pin does not exist for MCP41xxx
         * @param p_sclk: MBed pin for CLK
         * @param p_cs  : MBed pin for Chip Select. If NC, assumes that application manage /CS, default value is NC, not connected
         * @param p_reset: MBed pin to manage /RESET input. If NC, /RESET is not managed, default value is NC, not connected
         * @param p_shdn: MBed pin to manage /SHDN input. If NC, /SHDN is not managed, default value is NC, not connected
         * @param p_frequency: Frequency of the SPI interface (SCK), default value is 1MHz
         */
        CMCP4xxxx_SPI(const PinName p_mosi, const PinName p_miso, const PinName p_sclk, const PinName p_cs = NC, const PinName p_reset = NC, const PinName p_shdn = NC, const unsigned int p_frequency = 1000000);
    
        /** Destructor
         */
        virtual ~CMCP4xxxx_SPI();

        /** Used to return the unique instance of SPI instance
         */
        inline const SPI * operator * () { return (const SPI *)_spiInstance; };

        /** Send a write a command (WriteToPot1, WriteToPot2 or WriteBoth)
         *
         * @param p_command The command to execute: Write or Shutdown (See DS11195C-page 18)
         * @param p_value The potentiometer selection bits (See DS11195C-page 14 Clause 4.1 Modes of Operation)
         * @return 0x0000 on success, 0Xffff otherwise
         * Exemple:
         * @code
         * unsigned char potLevel;
         * ...
         * g_chipSelect.write(0);
         * g_digitalPot.Write(CMCP4xxxx_SPI::WriteToPot2, potLevel);
         * g_chipSelect.write(1);
         * ...
         * @endcode
         */
        unsigned short Write(const Commands p_command, const unsigned char p_value);
    
        /** Send a shutdown a command (ShutdownPot1, ShutdownPot2 or ShutdownBoth)
         *
         * @param p_command The command to execute: Write or Shutdown (See DS11195C-page 18)
         * @param p_value The potentiometer selection bits (See DS11195C-page 14 Clause 4.1 Modes of Operation)
         * @return 0x0000 on success, 0Xffff otherwise
         * Exemple:
         * @code
         * ...
         * g_chipSelect.write(0);
         * g_digitalPot.Write(CMCP4xxxx_SPI::ShutdownPot1);
         * g_chipSelect.write(1);
         * ...
         * @endcode
         */
        unsigned short Write(const Commands p_command);
    
         /** Write a NOP command
         */
        unsigned short Write();
    
       /** Reset the device
         * @code
         * unsigned char potLevel;
         * ...
         * g_chipSelect.write(0);
         * g_digitalPot.Reset();
         * g_chipSelect.write(1);
         * ...
         * @endcode
         */
        bool Reset();
    
        /** Shutdown the device
         */
        bool Shutdown(const bool p_set);
    
    private:
        /** Internal reference identifier
         */
        std::string _internalId;

    }; // End of class CMCP4xxxx_SPI

} // End of namespace MCP4xxxx_SPI

using namespace MCP4xxxx_SPI;

#endif // __MCP4xxxx_SPI_H__