com.qualcomm.hardware.modernrobotics.comm

Class ModernRoboticsReaderWriter

java.lang.Object

com.qualcomm.hardware.modernrobotics.comm.ModernRoboticsReaderWriter

public class ModernRoboticsReaderWriter
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	COMM_ERROR_READ
static java.lang.String	COMM_ERROR_WRITE
static java.lang.String	COMM_FAILURE_READ
static java.lang.String	COMM_FAILURE_WRITE
static java.lang.String	COMM_PAYLOAD_ERROR_READ
static java.lang.String	COMM_PAYLOAD_ERROR_WRITE
static java.lang.String	COMM_SYNC_LOST
static java.lang.String	COMM_TIMEOUT_READ
static java.lang.String	COMM_TIMEOUT_WRITE
static java.lang.String	COMM_TYPE_ERROR_READ
static java.lang.String	COMM_TYPE_ERROR_WRITE
static boolean	DEBUG
protected RobotUsbDevice	device
protected boolean	isSynchronized
static int	MAX_SEQUENTIAL_USB_ERROR_COUNT
static int	MS_COMM_ERROR_WAIT
static int	MS_FAILURE_WAIT
static int	MS_GARBAGE_COLLECTION_SPURT We run on a garbage collected system.
static int	MS_INTER_BYTE_TIMEOUT The timeouts defined by the MR USB spec are subtle.
static int	MS_MAX_TIMEOUT
static int	MS_REQUEST_RESPONSE_TIMEOUT
static int	MS_RESYNCH_TIMEOUT We made this up: we want to be very generous in trying to recover from failures as we read through possibly-old data trying to synchronize, and there's little harm in doing so
static int	MS_USB_HUB_LATENCY
protected int	msUsbReadRetryInterval
protected int	msUsbWriteRetryInterval
protected ModernRoboticsDatagram.AllocationContext<ModernRoboticsRequest>	requestAllocationContext
protected ModernRoboticsDatagram.AllocationContext<ModernRoboticsResponse>	responseAllocationContext
protected Deadline	responseDeadline
static java.lang.String	TAG
protected int	usbReadRetryCount
protected int	usbSequentialCommReadErrorCount
protected int	usbSequentialCommWriteErrorCount
protected int	usbWriteRetryCount

Constructor Summary

Constructors

Constructor and Description
ModernRoboticsReaderWriter(RobotUsbDevice device)

Method Summary

Modifier and Type	Method and Description
protected static java.lang.String	bufferToString(byte[] buffer)
void	close()
protected void	doExceptionBookkeeping()
protected void	logAndRethrowTimeout(RobotUsbTimeoutException e, ModernRoboticsRequest request, java.lang.String message)
protected void	logAndThrowProtocol(ModernRoboticsRequest request, ModernRoboticsResponse response, java.lang.String message)
protected void	logAndThrowProtocol(java.lang.String format, java.lang.Object... args)
void	read(boolean retry, int address, byte[] buffer, TimeWindow payloadTimeWindow)
protected void	readIncomingBytes(byte[] buffer, int ibFirst, int cbToRead, int msExtraTimeout, TimeWindow timeWindow, java.lang.String debugContext)
protected void	readOnce(int address, byte[] buffer, TimeWindow payloadTimeWindow)
protected ModernRoboticsResponse	readResponse(ModernRoboticsRequest request, TimeWindow payloadTimeWindow)
protected byte	readSingleByte(byte[] buffer, int msExtraTimeout, TimeWindow timeWindow, java.lang.String debugContext)
void	throwIfTooManySequentialCommErrors()
protected java.lang.String	timeoutMessage(java.lang.String root, RobotUsbTimeoutException e)
void	write(int address, byte[] buffer)
protected void	writeOnce(int address, byte[] buffer)

Methods inherited from class java.lang.Object

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

Field Detail

TAG

public static final java.lang.String TAG

See Also:

Constant Field Values

DEBUG

public static boolean DEBUG

MS_INTER_BYTE_TIMEOUT

public static int MS_INTER_BYTE_TIMEOUT

The timeouts defined by the MR USB spec are subtle. Our historical timeout of 100ms to read the header and the 100ms to read the payload was demonstrably insufficient, as teams were hitting the payload timeout in the wild. Per the MR spec, the payload timeout should be payload-length-dependent. Here's the skinny: The MR spec speaks thusly: "In order to detect a failure of too few Data payload bytes being received, a timeout is used. This timeout is set to 10mS. This timeout will start as a soon as the initial 0x55 is received. It is reset upon the arrival of each subsequent byte. [...] A similar timeout process may be performed by the host. The host may also use a timeout of 50mS for receipt of a response. If no response is received within 50mS, then it is assumed that either the USB VCP communication link is non-operational, or the controller power is not present"

MS_USB_HUB_LATENCY

public static int MS_USB_HUB_LATENCY

MS_REQUEST_RESPONSE_TIMEOUT

public static int MS_REQUEST_RESPONSE_TIMEOUT

MS_GARBAGE_COLLECTION_SPURT

public static int MS_GARBAGE_COLLECTION_SPURT

We run on a garbage collected system. That doesn't run very often, and doesn't run back to back, only one at a time, but when it does run it shuts things down for 15ms-40ms. One of those can happen in the middle of any of our timeouts. So we need to allow for same.

MS_RESYNCH_TIMEOUT

public static int MS_RESYNCH_TIMEOUT

We made this up: we want to be very generous in trying to recover from failures as we read through possibly-old data trying to synchronize, and there's little harm in doing so

MS_FAILURE_WAIT

public static int MS_FAILURE_WAIT

MS_COMM_ERROR_WAIT

public static int MS_COMM_ERROR_WAIT

MS_MAX_TIMEOUT

public static int MS_MAX_TIMEOUT

MAX_SEQUENTIAL_USB_ERROR_COUNT

public static int MAX_SEQUENTIAL_USB_ERROR_COUNT

COMM_FAILURE_READ

public static final java.lang.String COMM_FAILURE_READ

See Also:

Constant Field Values

COMM_FAILURE_WRITE

public static final java.lang.String COMM_FAILURE_WRITE

See Also:

Constant Field Values

COMM_TIMEOUT_READ

public static final java.lang.String COMM_TIMEOUT_READ

See Also:

Constant Field Values

COMM_TIMEOUT_WRITE

public static final java.lang.String COMM_TIMEOUT_WRITE

See Also:

Constant Field Values

COMM_ERROR_READ

public static final java.lang.String COMM_ERROR_READ

See Also:

Constant Field Values

COMM_ERROR_WRITE

public static final java.lang.String COMM_ERROR_WRITE

See Also:

Constant Field Values

COMM_SYNC_LOST

public static final java.lang.String COMM_SYNC_LOST

See Also:

Constant Field Values

COMM_PAYLOAD_ERROR_READ

public static final java.lang.String COMM_PAYLOAD_ERROR_READ

See Also:

Constant Field Values

COMM_PAYLOAD_ERROR_WRITE

public static final java.lang.String COMM_PAYLOAD_ERROR_WRITE

See Also:

Constant Field Values

COMM_TYPE_ERROR_READ

public static final java.lang.String COMM_TYPE_ERROR_READ

See Also:

Constant Field Values

COMM_TYPE_ERROR_WRITE

public static final java.lang.String COMM_TYPE_ERROR_WRITE

See Also:

Constant Field Values

device

protected final RobotUsbDevice device

usbSequentialCommReadErrorCount

protected int usbSequentialCommReadErrorCount

usbSequentialCommWriteErrorCount

protected int usbSequentialCommWriteErrorCount

usbReadRetryCount

protected int usbReadRetryCount

usbWriteRetryCount

protected int usbWriteRetryCount

msUsbReadRetryInterval

protected int msUsbReadRetryInterval

msUsbWriteRetryInterval

protected int msUsbWriteRetryInterval

isSynchronized

protected boolean isSynchronized

responseDeadline

protected Deadline responseDeadline

requestAllocationContext

protected ModernRoboticsDatagram.AllocationContext<ModernRoboticsRequest> requestAllocationContext

responseAllocationContext

protected ModernRoboticsDatagram.AllocationContext<ModernRoboticsResponse> responseAllocationContext

Constructor Detail

ModernRoboticsReaderWriter

public ModernRoboticsReaderWriter(RobotUsbDevice device)

Method Detail

throwIfTooManySequentialCommErrors

public void throwIfTooManySequentialCommErrors()
                                        throws RobotUsbTooManySequentialErrorsException

Throws:

RobotUsbTooManySequentialErrorsException

close

public void close()

read

public void read(boolean retry,
                 int address,
                 byte[] buffer,
                 TimeWindow payloadTimeWindow)
          throws RobotUsbException,
                 java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

readOnce

protected void readOnce(int address,
                        byte[] buffer,
                        TimeWindow payloadTimeWindow)
                 throws RobotUsbException,
                        java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

write

public void write(int address,
                  byte[] buffer)
           throws RobotUsbException,
                  java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

writeOnce

protected void writeOnce(int address,
                         byte[] buffer)
                  throws RobotUsbException,
                         java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

readResponse

protected ModernRoboticsResponse readResponse(ModernRoboticsRequest request,
                                              TimeWindow payloadTimeWindow)
                                       throws RobotUsbException,
                                              java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

readIncomingBytes

protected void readIncomingBytes(byte[] buffer,
                                 int ibFirst,
                                 int cbToRead,
                                 int msExtraTimeout,
                                 TimeWindow timeWindow,
                                 java.lang.String debugContext)
                          throws RobotUsbException,
                                 java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

readSingleByte

protected byte readSingleByte(byte[] buffer,
                              int msExtraTimeout,
                              TimeWindow timeWindow,
                              java.lang.String debugContext)
                       throws RobotUsbException,
                              java.lang.InterruptedException

Throws:

RobotUsbException

java.lang.InterruptedException

timeoutMessage

protected java.lang.String timeoutMessage(java.lang.String root,
                                          RobotUsbTimeoutException e)

doExceptionBookkeeping

protected void doExceptionBookkeeping()

logAndRethrowTimeout

protected void logAndRethrowTimeout(RobotUsbTimeoutException e,
                                    ModernRoboticsRequest request,
                                    java.lang.String message)
                             throws RobotUsbTimeoutException

Throws:

RobotUsbTimeoutException

logAndThrowProtocol

protected void logAndThrowProtocol(java.lang.String format,
                                   java.lang.Object... args)
                            throws RobotUsbProtocolException

Throws:

RobotUsbProtocolException

logAndThrowProtocol

protected void logAndThrowProtocol(ModernRoboticsRequest request,
                                   ModernRoboticsResponse response,
                                   java.lang.String message)
                            throws RobotUsbProtocolException

Throws:

RobotUsbProtocolException

bufferToString

protected static java.lang.String bufferToString(byte[] buffer)