XRT79L71_1 Datasheet, PDF (236/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
REV. 1.0.0
BIT NUMBER
NAME
2
Uncorrectable HEC Byte
Retain
1
COSET Polynomial Addi-
tion
0
Regenerate HEC Byte
Enable
TYPE
R/W
R/W
R/W
DESCRIPTION
Uncorrectable HEC Byte Retain:
This READ/WRITE bit-field permits the user to configure the
Receive ATM Cell Processor block to either automatically dis-
card or retain all incoming ATM cells that contain uncorrectable
HEC byte errors.
If the user implements this feature, then the Receive ATM Cell
Processor block will automatically retain any cells that fit into any
one of the following categories.
• ATM cells that contain multi-bit HEC byte errors.
• ATM cells that contain single-bit HEC byte errors, while the
Receive ATM Cell Processor block is operating in the
Detection Mode.
If the user does NOT implement this feature, then the Receive
ATM Cell Processor block will automatically discard any cells
that fit into any one of the above-mentioned categories. These
cells (along with un-erred or cells with correctable HEC byte
errors) will be retains for further processing.
0 - Configures the Receive ATM Cell Processor block to auto-
matically discard ALL incoming ATM cells that contain "uncor-
rectable" HEC byte errors. All remaining cells will be retained for
further processing.
1 - Configures the Receive ATM Cell Processor block to retain
ALL incoming ATM cells that contain uncorrectable HEC byte
errors for further processing.
COSET Polynomial Addition:
This READ/WRITE bit-field permits the user to configure the
Receive ATM Cell Processor block to account for the fact that
the HEC bytes (within the incoming ATM cell traffic) also include
the Modulo-2 addition of the Coset Polynomial (e.g., x^6 + x^4 +
x^2 + 1), when performing HEC Byte Verification.
0 - Configures the Receive ATM Cell Processor block to NOT
account for the Coset Polynomial within the HEC bytes of the
incoming ATM cells.
1 - Configures the Receive ATM Cell Processor block to account
for the Coset Polynomial within the HEC bytes of the incoming
ATM cells.
Regenerate HEC Byte Enable:
This READ/WRITE bit-field permits the user to configure the
Receive ATM Cell Processor block to automatically re-compute
and insert a new HEC byte into each incoming ATM cell that con-
tains an uncorrectable HEC byte.
0 - Does not configure the Receive ATM Cell Processor block to
compute and insert a new HEC byte into ATM cells that contains
an uncorrectable HEC byte error.
1 - Configures the Receive ATM Cell Processor block to com-
pute and insert a new HEC byte into any incoming ATM cell that
contains an uncorrectable HEC byte error.
NOTE: If the user wishes to implement this feature, then the user
must disable the Uncorrectable HEC Byte Discard
feature, by setting Bit 2 (Uncorrectable HEC Byte
Discard) within this register, to "0".
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