
XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
136
The user can configure the “Test Cell Generator” to
operate in the “One Shot” mode by writing a “1” into
this bit-field. Conversely, the user can configure the
“Test Cell Generator” to operate in the “Continuous”
Mode by writing a “0” into this bit-field.
4.3.1.3.1
If the Test Cell Generator is configured to operate in
the “One Shot” mode, then upon enabling the Test Cell
Generator (by inducing a “0” to “1” transition in the
“Test Cell Enable” field of this register), the Test Cell
The “One Shot” Mode
Generator will generate a “single burst” of 1024 test
cells. Afterward, the Test Cell Generator will stop and
will not produce any more test cells until the next “0”
to “1” transition in the “Test Cell Enable” bit-field.
If the Test Cell Generator is operating in the “One
Shot” Mode, the user can determine its “progress” in
its “Test Cell” production by reading Bit 1 (One Shot
Done) of the “Test Cell Control and Status Register”;
as depicted below.
If this “Read-Only” bit-field contains a “1” then the
Test Cell Generator has completed its generation of
the latest burst of 1024 Test Cells. However, if this
bit-field contains a “0”, then generation of this burst
of Test Cells is still in-process.
Note:
The contents within Bit 1 (One Shot Done) is only
relevant if the user is operating the Test Cell Generator in
the “One Shot” Mode.
4.3.1.3.2
The “Continuous” Mode
If the Test Cell Generator is configured to operate in the
“Continuous” mode, then upon enabling the Test Cell
Generator (by writing a “1” into the “Test Cell Enable”
bit-field in this register), the Test Cell Generator will
produce a continuous stream of Test Cells for the
duration that the Test Cell Generator is enabled.
4.3.1.4
The user can Enable the “production” of Test Cells by
writing a “1” to Bit 4 (Test Cell Enable) of the Test Cell
Control and Status Register, as depicted below.
Enabling the “Test Cell Generator”
Writing a “1” to this bit-field enables the “Test Cell
Generator/Receiver”. Writing a “0” disables the “Test
Cell Generator/Receiver”.
Once the Test Cell Generator has been enabled, it
will begin to either produce a continuous stream of
cells (if configured to operate in the “Continuous”
mode), or a single burst of 1024 cells (if configured to
operate in the ”O(jiān)ne Shot” mode.)
4.3.2
The Test Cell Receiver has the following characteris-
tics:
It checks the header bytes of all cells arriving at the
RxFIFO (within the Receive UTOPIA Interface
Block), in order to determine if they are (or are not)
Test Cells.
Characteristics of the Test Cell Receiver
Test Cell Control and Status Register (Address = 06h)
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
R/W
R/W
R/W
R/W
R/W
R/W
RO
RO
Test Cell Control and Status Register (Address = 06h)
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
R/W
R/W
R/W
R/W
R/W
R/W
RO
RO
Test Cell Control and Status Register (Address = 06h)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Unused
Test Cell Enable
Line/System One Shot Test One Shot Done
PRBS Lock
R/W
R/W
R/W
R/W
R/W
R/W
RO
RO