Diff: RHGenericSPI.h

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0:ab4e012489ef

diff -r 000000000000 -r ab4e012489ef RHGenericSPI.h
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+++ b/RHGenericSPI.h	Thu Oct 15 01:27:00 2015 +0000
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+// RHGenericSPI.h
+// Author: Mike McCauley (mikem@airspayce.com)
+// Copyright (C) 2011 Mike McCauley
+// Contributed by Joanna Rutkowska
+// $Id: RHGenericSPI.h,v 1.7 2014/04/14 08:37:11 mikem Exp $
+
+#ifndef RHGenericSPI_h
+#define RHGenericSPI_h
+
+#include <RadioHead.h>
+
+/////////////////////////////////////////////////////////////////////
+/// \class RHGenericSPI RHGenericSPI.h <RHGenericSPI.h>
+/// \brief Base class for SPI interfaces
+///
+/// This generic abstract class is used to encapsulate hardware or software SPI interfaces for 
+/// a variety of platforms.
+/// The intention is so that driver classes can be configured to use hardware or software SPI
+/// without changing the main code.
+///
+/// You must provide a subclass of this class to driver constructors that require SPI.
+/// A concrete subclass that encapsualates the standard Arduino hardware SPI and a bit-banged
+/// software implementation is included.
+///
+/// Do not directly use this class: it must be subclassed and the following abstract functions at least 
+/// must be implmented:
+/// - begin()
+/// - end() 
+/// - transfer()
+class RHGenericSPI 
+{
+public:
+
+    /// \brief Defines constants for different SPI modes
+    ///
+    /// Defines constants for different SPI modes
+    /// that can be passed to the constructor or setMode()
+    /// We need to define these in a device and platform independent way, because the
+    /// SPI implementation is different on each platform.
+    typedef enum
+    {
+	DataMode0 = 0, ///< SPI Mode 0: CPOL = 0, CPHA = 0
+	DataMode1,     ///< SPI Mode 1: CPOL = 0, CPHA = 1
+	DataMode2,     ///< SPI Mode 2: CPOL = 1, CPHA = 0
+	DataMode3,     ///< SPI Mode 3: CPOL = 1, CPHA = 1
+    } DataMode;
+
+    /// \brief Defines constants for different SPI bus frequencies
+    ///
+    /// Defines constants for different SPI bus frequencies
+    /// that can be passed to setFrequency().
+    /// The frequency you get may not be exactly the one according to the name.
+    /// We need to define these in a device and platform independent way, because the
+    /// SPI implementation is different on each platform.
+    typedef enum
+    {
+	Frequency1MHz = 0,  ///< SPI bus frequency close to 1MHz
+	Frequency2MHz,      ///< SPI bus frequency close to 2MHz
+	Frequency4MHz,      ///< SPI bus frequency close to 4MHz
+	Frequency8MHz,      ///< SPI bus frequency close to 8MHz
+	Frequency16MHz      ///< SPI bus frequency close to 16MHz
+    } Frequency;
+
+    /// \brief Defines constants for different SPI endianness
+    ///
+    /// Defines constants for different SPI endianness
+    /// that can be passed to setBitOrder()
+    /// We need to define these in a device and platform independent way, because the
+    /// SPI implementation is different on each platform.
+    typedef enum
+    {
+	BitOrderMSBFirst = 0,  ///< SPI MSB first
+	BitOrderLSBFirst,      ///< SPI LSB first
+    } BitOrder;
+
+    /// Constructor
+    /// Creates an instance of an abstract SPI interface.
+    /// Do not use this contructor directly: you must instead use on of the concrete subclasses provided 
+    /// such as RHHardwareSPI or RHSoftwareSPI
+    /// \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.
+    /// \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
+    RHGenericSPI(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
+    virtual uint8_t transfer(uint8_t data) = 0;
+
+    /// SPI Configuration methods
+    /// Enable SPI interrupts (if supported)
+    /// This can be used in an SPI slave to indicate when an SPI message has been received
+    virtual void attachInterrupt() {};
+
+    /// Disable SPI interrupts (if supported)
+    /// This can be used to diable the SPI interrupt in slaves where that is supported.
+    virtual void detachInterrupt() {};
+
+    /// Initialise the SPI library.
+    /// Call this after configuring and before using the SPI library
+    virtual void begin() = 0;
+
+    /// Disables the SPI bus (leaving pin modes unchanged). 
+    /// Call this after you have finished using the SPI interface
+    virtual void end() = 0;
+
+    /// Sets the bit order the SPI interface will use
+    /// Sets the order of the bits shifted out of and into the SPI bus, either 
+    /// LSBFIRST (least-significant bit first) or MSBFIRST (most-significant bit first). 
+    /// \param[in] bitOrder Bit order to be used: one of RHGenericSPI::BitOrder
+    virtual void setBitOrder(BitOrder bitOrder);
+
+    /// Sets the SPI data mode: that is, clock polarity and phase. 
+    /// See the Wikipedia article on SPI for details. 
+    /// \param[in] dataMode The mode to use: one of RHGenericSPI::DataMode
+    virtual void setDataMode(DataMode dataMode);
+
+    /// Sets the SPI clock divider relative to the system clock. 
+    /// On AVR based boards, the dividers available are 2, 4, 8, 16, 32, 64 or 128. 
+    /// The default setting is SPI_CLOCK_DIV4, which sets the SPI clock to one-quarter 
+    /// the frequency of the system clock (4 Mhz for the boards at 16 MHz). 
+    /// \param[in] frequency The data rate to use: one of RHGenericSPI::Frequency
+    virtual void setFrequency(Frequency frequency);
+
+protected:
+    /// The configure SPI Bus frequency, one of RHGenericSPI::Frequency
+    Frequency    _frequency; // Bus frequency, one of RHGenericSPI::Frequency
+
+    /// Bit order, one of RHGenericSPI::BitOrder
+    BitOrder     _bitOrder;  
+
+    /// SPI bus mode, one of RHGenericSPI::DataMode
+    DataMode     _dataMode;  
+};
+#endif