90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
// SoftwareSPI.h
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// Author: Chris Lapa (chris@lapa.com.au)
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// Copyright (C) 2014 Chris Lapa
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// Contributed by Chris Lapa
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#ifndef RHSoftwareSPI_h
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#define RHSoftwareSPI_h
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#include <RHGenericSPI.h>
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/////////////////////////////////////////////////////////////////////
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/// \class RHSoftwareSPI RHSoftwareSPI.h <RHSoftwareSPI.h>
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/// \brief Encapsulate a software SPI interface
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///
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/// This concrete subclass of RHGenericSPI enapsulates a bit-banged software SPI interface.
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/// Caution: this software SPI interface will be much slower than hardware SPI on most
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/// platforms.
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///
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/// \par Usage
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///
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/// Usage varies slightly depending on what driver you are using.
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///
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/// For RF22, for example:
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/// \code
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/// #include <RHSoftwareSPI.h>
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/// RHSoftwareSPI spi;
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/// RH_RF22 driver(SS, 2, spi);
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/// RHReliableDatagram(driver, CLIENT_ADDRESS);
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/// void setup()
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/// {
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/// spi.setPins(6, 5, 7); // Or whatever SPI pins you need
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/// ....
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/// }
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/// \endcode
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class RHSoftwareSPI : public RHGenericSPI
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{
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public:
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/// Constructor
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/// Creates an instance of a bit-banged software SPI interface.
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/// Sets the SPI pins to the defaults of
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/// MISO = 12, MOSI = 11, SCK = 13. If you need other assigments, call setPins() before
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/// calling manager.init() or driver.init().
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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. CAUTION: the achieved
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/// frequency will almost certainly be very much slower on most platforms. eg on Arduino Uno, the
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/// the clock rate is likely to be at best around 46kHz.
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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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RHSoftwareSPI(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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uint8_t transfer(uint8_t data);
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/// Initialise the software SPI library
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/// Call this after configuring the SPI interface and before using it to transfer data.
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/// Initializes the SPI bus by setting SCK, MOSI, and SS to outputs, pulling SCK and MOSI low, and SS high.
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void begin();
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/// Disables the SPI bus usually, in this case
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/// there is no hardware controller to disable.
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void end();
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/// Sets the pins used by this SoftwareSPIClass instance.
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/// The defaults are: MISO = 12, MOSI = 11, SCK = 13.
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/// \param[in] miso master in slave out pin used
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/// \param[in] mosi master out slave in pin used
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/// \param[in] sck clock pin used
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void setPins(uint8_t miso = 12, uint8_t mosi = 11, uint8_t sck = 13);
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private:
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/// Delay routine for bus timing.
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void delayPeriod();
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private:
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uint8_t _miso;
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uint8_t _mosi;
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uint8_t _sck;
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uint8_t _bitOrder;
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uint8_t _delayCounts;
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uint8_t _clockPolarity;
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uint8_t _clockPhase;
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};
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#endif
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