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PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
107
For more information on this bit selection, please see
Section 6.2.2.1.1.
Bit 4—TDPChk Pat (Transmit Data Path Integrity
Check Pattern Selection)
The Transmit Cell Processor is always checking for a
specific (Data Path Integrity Check) pattern in the
fifth octet of each cell that it reads from the Tx FIFO.
This pattern will exist in the 5th octet of the cell, prior
to the insertion of the HEC byte. This “Read/Write”
bit-field allows the user to specify the octet pattern
that the Transmit Cell Processor should be checking
for. The following table relates the contents of this bit
field to the octet pattern expected by the Transmit
Cell Processor.
For more information on this feature, please see
Section 6.2.2.6.
Bit 3—GFC Nibble-Field Insert Enable
This “Read/Write” bit-field allows the user to enable or
disable the GFC Nibble Field Serial Input port (TxGFC).
If the user enables this input port, then he/she can
externally insert the value of the GFC Nibble-field
into each outgoing cell. If this port remains disabled,
then the GFC Nibble field value will remain as written
into the Transmit UTOPIA Interface block, by the ATM
Layer processor.
Writing a “0” disables this serial port. Writing a “1”
enables this serial port.
For more information on this bit selection, please see
Section 6.2.2.3.
Bit 2—TDP (Transmit Data Path Integrity Test)
Error Interrupt Enable
This “Read/Write” bit-field allows the user to enable
or disable the “Data Path Integrity Test” interrupt.
Writing a “0” to this bit-field disables this interrupt.
Writing a “1” to this bit-field enables this interrupt.
Bit 1—IC (Idle Cell) HEC Byte Calculation Enable
This “Read/Write” bit allows the user to enable or dis-
able the calculation and the insertion of the HEC byte
into each outgoing Idle Cell.
Writing a “0” into this bit-field disables the “HEC Byte
Calculation and Insertion into Idle Cells” feature.
Writing a “1” into this bit-field enables this feature.
Note:
If this feature is disabled, then the Transmit Cell Pro-
cessor will, instead, write the contents of the “Tx CP Idle
Cell Pattern Header Byte 5” register (Address = 68h) into
the fifth octet position of each Idle cell.
For more details into the operation of Idle Cells,
please see Section 6.2.2.1.2.
Bit 0—TDP (Transmit Data Path Integrity Check)
Error Interrupt Status
This “Read Only” bit-field indicates whether or not the
“Data Path Integrity Test” interrupt has occurred
since the last reading of the Tx CP Control Register.
This interrupt will occur if the Transmit Cell Processor
detects a byte-pattern, in the fifth octet position of
each cell read from the TxFIFO, that differs from the
expected “Data Path Integrity Check” pattern.
A “1” in this bit-field indicates that this interrupt has
occurred since the last reading of the Tx CP Control
Register. A “0” in this bit-field indicates that this
interrupt has not occurred.
For more details on the Data Path Integrity Check,
please see Section 6.2.2.6.
TDPC
HK
P
AT
R
ESULT
0
Transmit Cell Processor expects an alternating 55h/AAh pattern for the value of the fifth octet of the
cells received from the Tx FIFO.
1
Transmit Cell Processor expects a constant 55h pattern for the value of the fifth octet of the cells
received from the Tx FIFO.