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