
XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
260
The content of these registers are the number of Idle
Cells that have been detected, by the Receive Cell
Processor, since the last read of these registers.
These registers are reset upon read.
7.3.2.3.2
The user can configure the Receive Cell Processor
to filter incoming user or OAM cells based upon the
value of their header bytes. The UNI provides the
user with three (3) options.
Disable the User Cell Filter.
Pass only those cells with header byte patterns
matching the settings of the User Cell Filter.
User Cell Filtering
Discard only those cells with header byte patterns
matching the settings of the User Cell Filter.
Each of these User-Cell Filtering Options are
discussed below.
Disable the User-Cell Filter
If the user disables the User-Cell Filter, within the
Receive Cell Processor, then all user cells (indepen-
dent of their header byte patterns) will be written into
the Rx FIFO, within the Receive UTOPIA Interface
block.
Writing a “1” to Bit 4 (User Cell Filter Enable) enables
the User Cell Filter. Whereas, writing a ‘0” to this bit-field
disables the User Cell Filter.
Enable the User Cell Filter
If the User Cell Filter is enabled, then the Receive
Cell Processor will be filtering user cells in one of two
possible manners.
Pass Only those cells with header bytes patterns
matching the User Cell Filter settings (e.g., the
contents of the “Rx CP User Cell Filter Pattern
Header Byte” registers), or
1.
2.
Discard only those cells with header byte patterns
matching the User Cell Filter settings.
The User (or Assigned) cell filtering criteria is defined
based upon the contents of 8 read/write registers.
These eight registers are the four “Rx CP User Cell
Filter Pattern Header byte” registers and the four “Rx
CP User Cell Filter Mask Header Byte” registers. In
short, when a user cell reaches the Receive Cell
Processor, the contents of each header byte of this
cell (bytes 1 through 4), will be compared against the
contents of the corresponding “Rx CP User Cell Filter
Pattern Header Byte” registers based upon constraints
specified by the contents of the “Rx CP User Cell
PMON Received Idle Cell Count—MSB (Address = 32h)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Rx Idle Cell Count—High Byte
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
PMON Received Idle Cell Count—LSB (Address = 33h)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Rx Idle Cell Count—Low Byte
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
RxCP Additional Configuration Register (Address = 4Dh)
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
User Cell Filter
Discard
User Cell Filter
Enable
Correction Threshold [1, 0]
Correction
Enable
Unused
RO
RO
R/W
R/W
R/W
R/W
R/W
RO