Class SPI

    • Constructor Detail

      • SPI

        public SPI​(SPI.Port port)
        Constructor.
        Parameters:
        port - the physical SPI port
    • Method Detail

      • setClockRate

        public final void setClockRate​(int hz)
        Configure the rate of the generated clock signal. The default value is 500,000 Hz. The maximum value is 4,000,000 Hz.
        Parameters:
        hz - The clock rate in Hertz.
      • setMSBFirst

        public final void setMSBFirst()
        Configure the order that bits are sent and received on the wire to be most significant bit first.
      • setLSBFirst

        public final void setLSBFirst()
        Configure the order that bits are sent and received on the wire to be least significant bit first.
      • setClockActiveLow

        public final void setClockActiveLow()
        Configure the clock output line to be active low. This is sometimes called clock polarity high or clock idle high.
      • setClockActiveHigh

        public final void setClockActiveHigh()
        Configure the clock output line to be active high. This is sometimes called clock polarity low or clock idle low.
      • setSampleDataOnLeadingEdge

        public final void setSampleDataOnLeadingEdge()
        Configure that the data is stable on the leading edge and the data changes on the trailing edge.
      • setSampleDataOnTrailingEdge

        public final void setSampleDataOnTrailingEdge()
        Configure that the data is stable on the trailing edge and the data changes on the leading edge.
      • setSampleDataOnFalling

        @Deprecated
        public final void setSampleDataOnFalling()
        Deprecated.
        Configure that the data is stable on the falling edge and the data changes on the rising edge. Note this gets reversed is setClockActiveLow is set.
      • setSampleDataOnRising

        @Deprecated
        public final void setSampleDataOnRising()
        Deprecated.
        use setSampleDataOnLeadingEdge() in most cases.
        Configure that the data is stable on the rising edge and the data changes on the falling edge. Note this gets reversed is setClockActiveLow is set.
      • setChipSelectActiveHigh

        public final void setChipSelectActiveHigh()
        Configure the chip select line to be active high.
      • setChipSelectActiveLow

        public final void setChipSelectActiveLow()
        Configure the chip select line to be active low.
      • write

        public int write​(byte[] dataToSend,
                         int size)
        Write data to the slave device. Blocks until there is space in the output FIFO.

        If not running in output only mode, also saves the data received on the MISO input during the transfer into the receive FIFO.

      • write

        public int write​(ByteBuffer dataToSend,
                         int size)
        Write data to the slave device. Blocks until there is space in the output FIFO.

        If not running in output only mode, also saves the data received on the MISO input during the transfer into the receive FIFO.

        Parameters:
        dataToSend - The buffer containing the data to send.
      • read

        public int read​(boolean initiate,
                        byte[] dataReceived,
                        int size)
        Read a word from the receive FIFO.

        Waits for the current transfer to complete if the receive FIFO is empty.

        If the receive FIFO is empty, there is no active transfer, and initiate is false, errors.

        Parameters:
        initiate - If true, this function pushes "0" into the transmit buffer and initiates a transfer. If false, this function assumes that data is already in the receive FIFO from a previous write.
      • read

        public int read​(boolean initiate,
                        ByteBuffer dataReceived,
                        int size)
        Read a word from the receive FIFO.

        Waits for the current transfer to complete if the receive FIFO is empty.

        If the receive FIFO is empty, there is no active transfer, and initiate is false, errors.

        Parameters:
        initiate - If true, this function pushes "0" into the transmit buffer and initiates a transfer. If false, this function assumes that data is already in the receive FIFO from a previous write.
        dataReceived - The buffer to be filled with the received data.
        size - The length of the transaction, in bytes
      • transaction

        public int transaction​(byte[] dataToSend,
                               byte[] dataReceived,
                               int size)
        Perform a simultaneous read/write transaction with the device.
        Parameters:
        dataToSend - The data to be written out to the device
        dataReceived - Buffer to receive data from the device
        size - The length of the transaction, in bytes
      • transaction

        public int transaction​(ByteBuffer dataToSend,
                               ByteBuffer dataReceived,
                               int size)
        Perform a simultaneous read/write transaction with the device.
        Parameters:
        dataToSend - The data to be written out to the device.
        dataReceived - Buffer to receive data from the device.
        size - The length of the transaction, in bytes
      • initAuto

        public void initAuto​(int bufferSize)
        Initialize automatic SPI transfer engine.

        Only a single engine is available, and use of it blocks use of all other chip select usage on the same physical SPI port while it is running.

        Parameters:
        bufferSize - buffer size in bytes
      • freeAuto

        public void freeAuto()
        Frees the automatic SPI transfer engine.
      • setAutoTransmitData

        public void setAutoTransmitData​(byte[] dataToSend,
                                        int zeroSize)
        Set the data to be transmitted by the engine.

        Up to 16 bytes are configurable, and may be followed by up to 127 zero bytes.

        Parameters:
        dataToSend - data to send (maximum 16 bytes)
        zeroSize - number of zeros to send after the data
      • startAutoRate

        public void startAutoRate​(double period)
        Start running the automatic SPI transfer engine at a periodic rate.

        initAuto(int) and setAutoTransmitData(byte[], int) must be called before calling this function.

        Parameters:
        period - period between transfers, in seconds (us resolution)
      • startAutoTrigger

        public void startAutoTrigger​(DigitalSource source,
                                     boolean rising,
                                     boolean falling)
        Start running the automatic SPI transfer engine when a trigger occurs.

        initAuto(int) and setAutoTransmitData(byte[], int) must be called before calling this function.

        Parameters:
        source - digital source for the trigger (may be an analog trigger)
        rising - trigger on the rising edge
        falling - trigger on the falling edge
      • stopAuto

        public void stopAuto()
        Stop running the automatic SPI transfer engine.
      • forceAutoRead

        public void forceAutoRead()
        Force the engine to make a single transfer.
      • readAutoReceivedData

        public int readAutoReceivedData​(ByteBuffer buffer,
                                        int numToRead,
                                        double timeout)
        Read data that has been transferred by the automatic SPI transfer engine.

        Transfers may be made a byte at a time, so it's necessary for the caller to handle cases where an entire transfer has not been completed.

        Each received data sequence consists of a timestamp followed by the received data bytes, one byte per word (in the least significant byte). The length of each received data sequence is the same as the combined size of the data and zeroSize set in setAutoTransmitData().

        Blocks until numToRead words have been read or timeout expires. May be called with numToRead=0 to retrieve how many words are available.

        Parameters:
        buffer - buffer where read words are stored
        numToRead - number of words to read
        timeout - timeout in seconds (ms resolution)
        Returns:
        Number of words remaining to be read
      • readAutoReceivedData

        public int readAutoReceivedData​(int[] buffer,
                                        int numToRead,
                                        double timeout)
        Read data that has been transferred by the automatic SPI transfer engine.

        Transfers may be made a byte at a time, so it's necessary for the caller to handle cases where an entire transfer has not been completed.

        Each received data sequence consists of a timestamp followed by the received data bytes, one byte per word (in the least significant byte). The length of each received data sequence is the same as the combined size of the data and zeroSize set in setAutoTransmitData().

        Blocks until numToRead words have been read or timeout expires. May be called with numToRead=0 to retrieve how many words are available.

        Parameters:
        buffer - array where read words are stored
        numToRead - number of words to read
        timeout - timeout in seconds (ms resolution)
        Returns:
        Number of words remaining to be read
      • getAutoDroppedCount

        public int getAutoDroppedCount()
        Get the number of bytes dropped by the automatic SPI transfer engine due to the receive buffer being full.
        Returns:
        Number of bytes dropped
      • initAccumulator

        public void initAccumulator​(double period,
                                    int cmd,
                                    int xferSize,
                                    int validMask,
                                    int validValue,
                                    int dataShift,
                                    int dataSize,
                                    boolean isSigned,
                                    boolean bigEndian)
        Initialize the accumulator.
        Parameters:
        period - Time between reads
        cmd - SPI command to send to request data
        xferSize - SPI transfer size, in bytes
        validMask - Mask to apply to received data for validity checking
        validValue - After validMask is applied, required matching value for validity checking
        dataShift - Bit shift to apply to received data to get actual data value
        dataSize - Size (in bits) of data field
        isSigned - Is data field signed?
        bigEndian - Is device big endian?
      • freeAccumulator

        public void freeAccumulator()
        Frees the accumulator.
      • resetAccumulator

        public void resetAccumulator()
        Resets the accumulator to zero.
      • setAccumulatorCenter

        public void setAccumulatorCenter​(int center)
        Set the center value of the accumulator.

        The center value is subtracted from each value before it is added to the accumulator. This is used for the center value of devices like gyros and accelerometers to make integration work and to take the device offset into account when integrating.

      • setAccumulatorDeadband

        public void setAccumulatorDeadband​(int deadband)
        Set the accumulator's deadband.
      • getAccumulatorLastValue

        public int getAccumulatorLastValue()
        Read the last value read by the accumulator engine.
      • getAccumulatorValue

        public long getAccumulatorValue()
        Read the accumulated value.
        Returns:
        The 64-bit value accumulated since the last Reset().
      • getAccumulatorCount

        public int getAccumulatorCount()
        Read the number of accumulated values.

        Read the count of the accumulated values since the accumulator was last Reset().

        Returns:
        The number of times samples from the channel were accumulated.
      • getAccumulatorAverage

        public double getAccumulatorAverage()
        Read the average of the accumulated value.
        Returns:
        The accumulated average value (value / count).
      • getAccumulatorOutput

        public void getAccumulatorOutput​(AccumulatorResult result)
        Read the accumulated value and the number of accumulated values atomically.

        This function reads the value and count atomically. This can be used for averaging.

        Parameters:
        result - AccumulatorResult object to store the results in.
      • setAccumulatorIntegratedCenter

        public void setAccumulatorIntegratedCenter​(double center)
        Set the center value of the accumulator integrator.

        The center value is subtracted from each value*dt before it is added to the integrated value. This is used for the center value of devices like gyros and accelerometers to take the device offset into account when integrating.

      • getAccumulatorIntegratedValue

        public double getAccumulatorIntegratedValue()
        Read the integrated value. This is the sum of (each value * time between values).
        Returns:
        The integrated value accumulated since the last Reset().
      • getAccumulatorIntegratedAverage

        public double getAccumulatorIntegratedAverage()
        Read the average of the integrated value. This is the sum of (each value times the time between values), divided by the count.
        Returns:
        The average of the integrated value accumulated since the last Reset().