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RHSoftwareSPI.h

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+// SoftwareSPI.h
+// Author: Chris Lapa (chris@lapa.com.au)
+// Copyright (C) 2014 Chris Lapa
+// Contributed by Chris Lapa
+
+#ifndef RHSoftwareSPI_h
+#define RHSoftwareSPI_h
+
+#include <RHGenericSPI.h>
+
+/////////////////////////////////////////////////////////////////////
+/// \class RHSoftwareSPI RHSoftwareSPI.h <RHSoftwareSPI.h>
+/// \brief Encapsulate a software SPI interface
+///
+/// This concrete subclass of RHGenericSPI enapsulates a bit-banged software SPI interface.
+/// Caution: this software SPI interface will be much slower than hardware SPI on most
+/// platforms.
+///
+/// SPI transactions are not supported, and associated functions do nothing.
+///
+/// \par Usage
+///
+/// Usage varies slightly depending on what driver you are using.
+///
+/// For RF22, for example:
+/// \code
+/// #include <RHSoftwareSPI.h>
+/// RHSoftwareSPI spi;
+/// RH_RF22 driver(SS, 2, spi);
+/// RHReliableDatagram(driver, CLIENT_ADDRESS);
+/// void setup()
+/// {
+///    spi.setPins(6, 5, 7); // Or whatever SPI pins you need
+///    ....
+/// }
+/// \endcode
+class RHSoftwareSPI : public RHGenericSPI 
+{
+public:
+
+    /// Constructor
+    /// Creates an instance of a bit-banged software SPI interface.
+    /// Sets the SPI pins to the defaults of 
+    /// MISO = 12, MOSI = 11, SCK = 13. If you need other assigments, call setPins() before
+    /// calling manager.init() or driver.init().
+    /// \param[in] frequency One of RHGenericSPI::Frequency to select the SPI bus frequency. The frequency
+    /// is mapped to the closest available bus frequency on the platform. CAUTION: the achieved
+    /// frequency will almost certainly be very much slower on most platforms. eg on Arduino Uno, the
+    /// the clock rate is likely to be at best around 46kHz.
+    /// \param[in] bitOrder Select the SPI bus bit order, one of RHGenericSPI::BitOrderMSBFirst or 
+    /// RHGenericSPI::BitOrderLSBFirst.
+    /// \param[in] dataMode Selects the SPI bus data mode. One of RHGenericSPI::DataMode
+    RHSoftwareSPI(Frequency frequency = Frequency1MHz, BitOrder bitOrder = BitOrderMSBFirst, DataMode dataMode = DataMode0);
+
+    /// Transfer a single octet to and from the SPI interface
+    /// \param[in] data The octet to send
+    /// \return The octet read from SPI while the data octet was sent.
+    uint8_t transfer(uint8_t data);
+
+    /// Initialise the software SPI library
+    /// Call this after configuring the SPI interface and before using it to transfer data.
+    /// Initializes the SPI bus by setting SCK, MOSI, and SS to outputs, pulling SCK and MOSI low, and SS high. 
+    void begin();
+
+    /// Disables the SPI bus usually, in this case
+    /// there is no hardware controller to disable.
+    void end();
+
+    /// Sets the pins used by this SoftwareSPIClass instance.
+    /// The defaults are: MISO = 12, MOSI = 11, SCK = 13.
+    /// \param[in] miso master in slave out pin used
+    /// \param[in] mosi master out slave in pin used
+    /// \param[in] sck clock pin used
+    void setPins(uint8_t miso = 12, uint8_t mosi = 11, uint8_t sck = 13);
+
+private:
+
+    /// Delay routine for bus timing.
+    void delayPeriod();
+
+private:
+    uint8_t _miso;
+    uint8_t _mosi;
+    uint8_t _sck;
+    uint8_t _delayCounts;
+    uint8_t _clockPolarity;
+    uint8_t _clockPhase;
+};
+
+#endif