á
PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
67
Setting this bit-field to “1”, followed by a “0” to “1”
transition in the “Test Cell Enable” bit field (Bit 4 of
this register), causes the Test Cell Generator to oper-
ate in the “One Shot” Mode, and generate a single
burst of 1024 test cells. Afterwards the Test Cell Gen-
erator will halt, and will cease the production of new
test cells, until the next “0” to “1” transition occurs in
the “Test Cell Enable” bit field.
Conversely, setting this bit-field to “0”, followed by a
“0” to “1” transition in the “Test Cell Enable” bit field,
causes the Test Cell Generator to operate in the
“Continuous” Mode. When the Test Cell Generator is
operating in the “Continuous” mode, it will produce a
“continuous” stream of Test Cells, for the duration
that the “Test Cell Enable” bit-field is set to “1”.
Bit 1—One Shot Done
This “Read-Only” bit-field allows the user to monitor
the status of the Test Cell Generator, while it is
operating in the “One Shot” Mode. This bit-field will
be set to “1”, when the Test Cell Generator has com-
pleted its generator of the “burst” of the 1024 test
cells. Conversely, this bit-field will be set to “0” while
“test cell generation” is “in process”.
Note:
This bit-field has no meaning if the Test Cell Gener-
ator is operating in the “Continuous” Mode.
Bit 0—PRBS (Pseudo-Random Byte Sequence)
Lock
This “Read-Only” bit field indicates whether or not the
“Test Cell Receiver” has acquired “PRBS Lock” with
the payload data of the incoming test cells. Once the
“Test Cell Receiver” has acquired “PRBS Lock” with
this data, then it can begin to perform error-checking
on the incoming test cells.
3.3.2.8
Test Cell Header Byte-1
The “Read/Write” bit-fields, within this register; along
with those bit-fields within the “Test Cell Header Byte-
2 through -4” registers; allows the user to define the
header byte patterns for each of the “test cells” that
will be generated by the Test Cell Generator. This
particular register allows the user to define the pat-
tern for the first octet of these test cells.
3.3.2.9
Test Cell Header Byte-2
Address = 07h, Future Use
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Address = 08h, Test Cell Header Byte-1
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Test Cell Header Byte 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
1
0
0
0
1
Address = 09h, Test Cell Header Byte-2
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Test Cell Header Byte 2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
1
0
0
0
1
0