SPI

java.lang.Object
- edu.wpi.first.wpilibj.SPI

public class SPI
extends java.lang.Object

Represents a SPI bus port.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class SPI.Port

Nested Classes
Modifier and Type	Class and Description
`static class`	`SPI.Port`

Constructor Summary

Constructors
Constructor and Description

SPI(SPI.Port port)
Constructor.

Constructors
Constructor and Description
`SPI(SPI.Port port)` Constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`forceAutoRead()` Force the engine to make a single transfer.
`void`	`free()` Free the resources used by this object.
`void`	`freeAccumulator()` Frees the accumulator.
`void`	`freeAuto()` Frees the automatic SPI transfer engine.
`double`	`getAccumulatorAverage()` Read the average of the accumulated value.
`int`	`getAccumulatorCount()` Read the number of accumulated values.
`int`	`getAccumulatorLastValue()` Read the last value read by the accumulator engine.
`void`	`getAccumulatorOutput(AccumulatorResult result)` Read the accumulated value and the number of accumulated values atomically.
`long`	`getAccumulatorValue()` Read the accumulated value.
`int`	`getAutoDroppedCount()` Get the number of bytes dropped by the automatic SPI transfer engine due to the receive buffer being full.
`void`	`initAccumulator(double period, int cmd, int xferSize, int validMask, int validValue, int dataShift, int dataSize, boolean isSigned, boolean bigEndian)` Initialize the accumulator.
`void`	`initAuto(int bufferSize)` Initialize automatic SPI transfer engine.
`int`	`read(boolean initiate, byte[] dataReceived, int size)` Read a word from the receive FIFO.
`int`	`read(boolean initiate, java.nio.ByteBuffer dataReceived, int size)` Read a word from the receive FIFO.
`int`	`readAutoReceivedData(byte[] buffer, int numToRead, double timeout)` Read data that has been transferred by the automatic SPI transfer engine.
`int`	`readAutoReceivedData(java.nio.ByteBuffer buffer, int numToRead, double timeout)` Read data that has been transferred by the automatic SPI transfer engine.
`void`	`resetAccumulator()` Resets the accumulator to zero.
`void`	`setAccumulatorCenter(int center)` Set the center value of the accumulator.
`void`	`setAccumulatorDeadband(int deadband)` Set the accumulator's deadband.
`void`	`setAutoTransmitData(byte[] dataToSend, int zeroSize)` Set the data to be transmitted by the engine.
`void`	`setChipSelectActiveHigh()` Configure the chip select line to be active high.
`void`	`setChipSelectActiveLow()` Configure the chip select line to be active low.
`void`	`setClockActiveHigh()` Configure the clock output line to be active high.
`void`	`setClockActiveLow()` Configure the clock output line to be active low.
`void`	`setClockRate(int hz)` Configure the rate of the generated clock signal.
`void`	`setLSBFirst()` Configure the order that bits are sent and received on the wire to be least significant bit first.
`void`	`setMSBFirst()` Configure the order that bits are sent and received on the wire to be most significant bit first.
`void`	`setSampleDataOnFalling()` Configure that the data is stable on the falling edge and the data changes on the rising edge.
`void`	`setSampleDataOnRising()` Configure that the data is stable on the rising edge and the data changes on the falling edge.
`void`	`startAutoRate(double period)` Start running the automatic SPI transfer engine at a periodic rate.
`void`	`startAutoTrigger(DigitalSource source, boolean rising, boolean falling)` Start running the automatic SPI transfer engine when a trigger occurs.
`void`	`stopAuto()` Stop running the automatic SPI transfer engine.
`int`	`transaction(byte[] dataToSend, byte[] dataReceived, int size)` Perform a simultaneous read/write transaction with the device.
`int`	`transaction(java.nio.ByteBuffer dataToSend, java.nio.ByteBuffer dataReceived, int size)` Perform a simultaneous read/write transaction with the device.
`int`	`write(byte[] dataToSend, int size)` Write data to the slave device.
`int`	`write(java.nio.ByteBuffer dataToSend, int size)` Write data to the slave device.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SPI
```
public SPI(SPI.Port port)
```
    Constructor.
    
    Parameters:
    
    port - the physical SPI port
- Method Detail
  - free
```
public void free()
```
    Free the resources used by this object.
  - 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.
  - setSampleDataOnFalling
```
public final void setSampleDataOnFalling()
```
    Configure that the data is stable on the falling edge and the data changes on the rising edge.
  - setSampleDataOnRising
```
public final void setSampleDataOnRising()
```
    Configure that the data is stable on the rising edge and the data changes on the falling edge.
  - 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(java.nio.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,
                java.nio.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(java.nio.ByteBuffer dataToSend,
                       java.nio.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(java.nio.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.
    Blocks until numToRead bytes have been read or timeout expires. May be called with numToRead=0 to retrieve how many bytes are available.
    
    Parameters:
    
    buffer - buffer where read bytes are stored
    
    numToRead - number of bytes to read
    
    timeout - timeout in seconds (ms resolution)
    
    Returns:
    
    Number of bytes remaining to be read
  - readAutoReceivedData
```
public int readAutoReceivedData(byte[] 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.
    Blocks until numToRead bytes have been read or timeout expires. May be called with numToRead=0 to retrieve how many bytes are available.
    
    Parameters:
    
    buffer - array where read bytes are stored
    
    numToRead - number of bytes to read
    
    timeout - timeout in seconds (ms resolution)
    
    Returns:
    
    Number of bytes 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.

Class SPI

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SPI

Method Detail

free

setClockRate

setMSBFirst

setLSBFirst

setClockActiveLow

setClockActiveHigh

setSampleDataOnFalling

setSampleDataOnRising

setChipSelectActiveHigh

setChipSelectActiveLow

write

write

read

read

transaction

transaction

initAuto

freeAuto

setAutoTransmitData

startAutoRate

startAutoTrigger

stopAuto

forceAutoRead

readAutoReceivedData

readAutoReceivedData

getAutoDroppedCount

initAccumulator

freeAccumulator

resetAccumulator

setAccumulatorCenter

setAccumulatorDeadband

getAccumulatorLastValue

getAccumulatorValue

getAccumulatorCount

getAccumulatorAverage

getAccumulatorOutput