Package edu.wpi.first.hal

Class CANAPIJNI

java.lang.Object

edu.wpi.first.hal.JNIWrapper

edu.wpi.first.hal.CANAPIJNI

public class CANAPIJNI
extends JNIWrapper

CAN API HAL JNI Functions.

See Also:

"hal/CANAPI.h"

Nested Class Summary

Nested classes/interfaces inherited from class edu.wpi.first.hal.JNIWrapper

JNIWrapper.Helper

Method Summary

Modifier and Type	Method	Description
static void	cleanCAN(int handle)	Frees a CAN device.
static long	getCANPacketBaseTime()	Reads the current value of the millisecond-resolution timer that the CAN API functions use as a time base.
static int	initializeCAN(int manufacturer, int deviceId, int deviceType)	Initializes a CAN device.
static boolean	readCANPacketLatest(int handle, int apiId, CANData data)	Reads a CAN packet.
static boolean	readCANPacketNew(int handle, int apiId, CANData data)	Reads a new CAN packet.
static boolean	readCANPacketTimeout(int handle, int apiId, int timeoutMs, CANData data)	Reads a CAN packet.
static void	stopCANPacketRepeating(int handle, int apiId)	Stops a repeating packet with a specific ID.
static void	writeCANPacket(int handle, byte[] data, int apiId)	Writes a packet to the CAN device with a specific ID.
static int	writeCANPacketNoThrow(int handle, byte[] data, int apiId)	Writes a packet to the CAN device with a specific ID without throwing on error.
static void	writeCANPacketRepeating(int handle, byte[] data, int apiId, int repeatMs)	Writes a repeating packet to the CAN device with a specific ID.
static int	writeCANPacketRepeatingNoThrow(int handle, byte[] data, int apiId, int repeatMs)	Writes a repeating packet to the CAN device with a specific ID without throwing on error.
static void	writeCANRTRFrame(int handle, int length, int apiId)	Writes an RTR frame of the specified length to the CAN device with the specific ID.
static int	writeCANRTRFrameNoThrow(int handle, int length, int apiId)	Writes an RTR frame of the specified length to the CAN device with the specific ID without throwing on error.

Methods inherited from class edu.wpi.first.hal.JNIWrapper

forceLoad, suppressUnused

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getCANPacketBaseTime

public static long getCANPacketBaseTime()

Reads the current value of the millisecond-resolution timer that the CAN API functions use as a time base.

Returns:

Current value of timer used as a base time by the CAN API in milliseconds.

See Also:

"HAL_GetCANPacketBaseTime"

initializeCAN

public static int initializeCAN(int manufacturer, int deviceId, int deviceType)

Initializes a CAN device.

These follow the FIRST standard CAN layout. https://docs.wpilib.org/en/stable/docs/software/can-devices/can-addressing.html

Parameters:

manufacturer - the can manufacturer

deviceId - the device ID (0-63)

deviceType - the device type

Returns:

the created CAN handle

See Also:

"HAL_InitializeCAN"

cleanCAN

public static void cleanCAN(int handle)

Frees a CAN device.

Parameters:

handle - the CAN handle

See Also:

"HAL_CleanCAN"

writeCANPacket

public static void writeCANPacket(int handle, byte[] data, int apiId)

Writes a packet to the CAN device with a specific ID.

This ID is 10 bits.

Parameters:

handle - the CAN handle

data - the data to write (0-8 bytes)

apiId - the ID to write (0-1023 bits)

See Also:

"HAL_WriteCANPacket"

writeCANPacketRepeating

public static void writeCANPacketRepeating(int handle, byte[] data, int apiId, int repeatMs)

Writes a repeating packet to the CAN device with a specific ID.

This ID is 10 bits.

The RoboRIO will automatically repeat the packet at the specified interval

Parameters:

handle - the CAN handle

data - the data to write (0-8 bytes)

apiId - the ID to write (0-1023)

repeatMs - the period to repeat in ms

See Also:

"HAL_WriteCANPacketRepeating"

writeCANRTRFrame

public static void writeCANRTRFrame(int handle, int length, int apiId)

Writes an RTR frame of the specified length to the CAN device with the specific ID.

By spec, the length must be equal to the length sent by the other device, otherwise behavior is unspecified.

Parameters:

handle - the CAN handle

length - the length of data to request (0-8)

apiId - the ID to write (0-1023)

See Also:

"HAL_WriteCANRTRFrame"

writeCANPacketNoThrow

public static int writeCANPacketNoThrow(int handle, byte[] data, int apiId)

Writes a packet to the CAN device with a specific ID without throwing on error.

This ID is 10 bits.

Parameters:

handle - the CAN handle

data - the data to write (0-8 bytes)

apiId - the ID to write (0-1023 bits)

Returns:

Error status variable. 0 on success.

See Also:

"HAL_WriteCANPacket"

writeCANPacketRepeatingNoThrow

public static int writeCANPacketRepeatingNoThrow(int handle, byte[] data, int apiId, int repeatMs)

Writes a repeating packet to the CAN device with a specific ID without throwing on error.

This ID is 10 bits.

The RoboRIO will automatically repeat the packet at the specified interval

Parameters:

handle - the CAN handle

data - the data to write (0-8 bytes)

apiId - the ID to write (0-1023)

repeatMs - the period to repeat in ms

Returns:

Error status variable. 0 on success.

See Also:

"HAL_WriteCANPacketRepeating"

writeCANRTRFrameNoThrow

public static int writeCANRTRFrameNoThrow(int handle, int length, int apiId)

Writes an RTR frame of the specified length to the CAN device with the specific ID without throwing on error.

By spec, the length must be equal to the length sent by the other device, otherwise behavior is unspecified.

Parameters:

handle - the CAN handle

length - the length of data to request (0-8)

apiId - the ID to write (0-1023)

Returns:

Error status variable. 0 on success.

See Also:

"HAL_WriteCANRTRFrame"

stopCANPacketRepeating

public static void stopCANPacketRepeating(int handle, int apiId)

Stops a repeating packet with a specific ID.

This ID is 10 bits.

Parameters:

handle - the CAN handle

apiId - the ID to stop repeating (0-1023)

See Also:

"HAL_StopCANPacketRepeating"

readCANPacketNew

public static boolean readCANPacketNew(int handle, int apiId, CANData data)

Reads a new CAN packet.

This will only return properly once per packet received. Multiple calls without receiving another packet will return false.

Parameters:

handle - the CAN handle

apiId - the ID to read (0-1023)

data - the packet data (8 bytes)

Returns:

true on success, false on error

See Also:

"HAL_ReadCANPacketNew"

readCANPacketLatest

public static boolean readCANPacketLatest(int handle, int apiId, CANData data)

Reads a CAN packet. The will continuously return the last packet received, without accounting for packet age.

Parameters:

handle - the CAN handle

apiId - the ID to read (0-1023)

data - the packet data (8 bytes)

Returns:

true on success, false on error

See Also:

"HAL_ReadCANPacketLatest"

readCANPacketTimeout

public static boolean readCANPacketTimeout(int handle, int apiId, int timeoutMs, CANData data)

Reads a CAN packet. The will return the last packet received until the packet is older then the requested timeout. Then it will return false.

Parameters:

handle - the CAN handle

apiId - the ID to read (0-1023)

timeoutMs - the timeout time for the packet

data - the packet data (8 bytes)

Returns:

true on success, false on error

See Also:

"HAL_ReadCANPacketTimeout"