
XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
66
(Address = 1Fh)
Bit 0—One Second Interrupt Status
This “Reset-upon-Read” bit-field indicates whether or
not the “One Second” interrupt has occurred, since
the last read of this register.
If this bit-field is “0”, then a “One Second” interrupt
has not occurred.
However, if this bit-field is “1”, then the “One Second”
interrupt has occurred.
3.3.2.7
Test Cell Control and Status Register
Bit 4—Test Cell (Generator/Receiver) Enable
This “Read/Write” bit-field allows the user to perform
some testing on the UNI, by activating the “Test and
Diagnostic” section. Once the user has activated this
section, then the “internal” Test Cell Generator and
Test Cell Receiver will be active. The Test Cell Gener-
ator will generate cells in accordance with a “traffic
pattern” as dictated by the user in his/her selection
within the “One Shot Test” bit field. The Test Cell
Generator will generate test cells that contain the
header byte pattern, as specified (by the user) in the
“Test Cell Header Byte-1 through 4” registers. The
payload portion of each of these test cells will be
“filled with” data generated by a Pseudo-Random
Byte Sequence (PRBS) generator.
The Test Cell Receiver functions as the “Test Cell
Sink” and bit-error analyzer. The Test Cell Receiver
will recognize each of these test cells by their header
byte patterns. Further, the Test Cell Receiver will
attempt to analyze the payload data (within each of
these test cells) by acquiring “PRBS Lock” on the
data. Once the Test Cell Receiver has “PRBS Lock”
on this test cell payload data, then it can perform
error-checking and error-reporting on this data. The
“Test and Diagnostic” section of the UNI performs
error reporting by updating the “Test Cell Error
Accumulator” registers.
Writing a “1” to this bit-field enables the “Test Cell
Generator/Receiver”. Writing a “0” disables the “Test
Cell Generator/Receiver”.
For more information on these features, please see
Section 4.3.
Bit 3—Line*/System (Side Testing)
This “Read/Write” bit-field allows the user to specify
whether or not he/she wishes to run a “Line Side”
test or a “System Side” test. If the user selects a
“Line Side” test, then the “Test Cell Generator” will
generate and insert test cells into the TxFIFO (within
the UNI). These test cells will ultimately be transmit-
ted out onto the DS3 line. In the “Receive Path”,
those test cells that reach the RxFIFO will be identi-
fied by their header byte patterns, and routed into the
“Test Cell Receiver” where they will be checked for bit
errors.
If the user selects a “System side” test then the “Test
Cell Generator” will generate and insert the test cells
into the RxFIFO, where they can be read out and pro-
cessed by the ATM Layer processor, via the Receive
UTOPIA Interface block. In the transmit path, those
test cells that reach the TxFIFO will be identified by
their header byte patterns, and routed to the “Test
Cell Receiver” where they will be checked for bit errors.
Writing a “0” to this bit-field selects the “Line Side”
test. Writing a “1” to this bit-field selects the “System
Side” test.
Note:
The System-side test is not supported by this ver-
sion of the XRT7245 DS3 UNI. Therefore, the user should
always write a “0” into this bit-field.
Bit 2—One Shot Test
This “Read/Write” bit-field allows the user to specify
which of two “traffic options” that he/she would like
the test cells to be generated. The UNI “Test and Di-
agnostic” section supports the following traffic op-
tions:
“One Shot” Mode—A single burst of 1024 Test
Cells are generated
“Continuous” Mode—A continuous stream of Test
Cells are generated for the duration that the “Test
Cell Generator/Receiver” receiver are enabled.
Address = 06h, Test Cell Control and Status Register
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Unused
Test Cell Enable
Line*/System
One Shot Test
One Shot Done
PRBS Lock
RO
RO
RO
R/W
R/W
R/W
RO
RO
0
0
0
0
0
0
0
0