tool/mbed/mbed-sdk/libraries/tests/libs/SPIHalfDuplex/SPIHalfDuplex.h

   1 /* mbed Microcontroller Library - SPIHalfDuplex
   2  * Copyright (c) 2010-2011 ARM Limited. All rights reserved.
   3  */
   4 #ifndef MBED_SPIHALFDUPLEX_H
   5 #define MBED_SPIHALFDUPLEX_H
   6
   7 #include "platform.h"
   8
   9 #if DEVICE_SPI
  10
  11 #include "SPI.h"
  12
  13 namespace mbed {
  14
  15 /** A SPI half-duplex master, used for communicating with SPI slave devices
  16  * over a shared data line.
  17  *
  18  * The default format is set to 8-bits for both master and slave, and a
  19  * clock frequency of 1MHz
  20  *
  21  * Most SPI devies will also require Chip Select and Reset signals. These
  22  * can be controlled using <DigitalOut> pins.
  23  *
  24  * Although this is for a shared data line, both MISO and MOSI are defined,
  25  * and should be tied together externally to the mbed. This class handles
  26  * the tri-stating of the MOSI pin.
  27  *
  28  * Example:
  29  * @code
  30  * // Send a byte to a SPI half-duplex slave, and record the response
  31  *
  32  * #include "mbed.h"
  33  *
  34  * SPIHalfDuplex device(p5, p6, p7) // mosi, miso, sclk
  35  *
  36  * int main() {
  37  *     int respone = device.write(0xAA);
  38  * }
  39  * @endcode
  40  */
  41
  42 class SPIHalfDuplex : public SPI {
  43
  44 public:
  45
  46     /** Create a SPI half-duplex master connected to the specified pins
  47      *
  48      * Pin Options:
  49      *  (5, 6, 7) or (11, 12, 13)
  50      *
  51      *  mosi or miso can be specfied as NC if not used
  52      *
  53      *  @param mosi SPI Master Out, Slave In pin
  54      *  @param miso SPI Master In, Slave Out pin
  55      *  @param sclk SPI Clock pin
  56      *  @param name (optional) A string to identify the object
  57      */
  58     SPIHalfDuplex(PinName mosi, PinName miso, PinName sclk);
  59
  60     /** Write to the SPI Slave and return the response
  61      *
  62      *  @param value Data to be sent to the SPI slave
  63      *
  64      *  @returns
  65      *    Response from the SPI slave
  66      */
  67     virtual int write(int value);
  68
  69     /** Set the number of databits expected from the slave, from 4-16
  70      *
  71      *  @param sbits Number of expected bits in the slave response
  72      */
  73     void slave_format(int sbits);
  74
  75 protected:
  76     PinName _mosi;
  77     PinName _miso;
  78     int     _sbits;
  79 }; // End of class
  80
  81 } // End of namespace mbed
  82
  83 #endif
  84
  85 #endif