![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT94L33IB-L_datasheet_100163/XRT94L33IB-L_412.png)
XRT94L33
xr
Rev.1.2.0.
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
412
Receive ATM Cell Processor Block – Receive ATM Control Register – Byte 1 (Address = 0xN702)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
GFC
Extraction
Enable
HEC Byte
Correction
Enable
Uncorrectable
HEC Byte
Error Discard
COSET
Polynomial
Addition
Regenerate
HEC Byte
Enable
R/O
R/W
0
X
0
1
0
Setting this bit-field to “0” disables “Correction Mode” operation within the HEC Byte Verification Block.
Conversely, setting this bit-field to “1” enables “Correction Mode” operation within the HEC Byte Verification
Block.
The “Detection” State
Unless “Correction Mode” operation is disabled (per the procedure described above), the HEC Byte
Verification Block will transition into the “Detection” State (within the “HEC Byte Error Detection/Correction”
algorithm.
Whenever the “HEC Byte Verification” block is operating in the “Detection” State, then ALL errored cells (e.g.,
those incoming cells that contain single-bit errors and multi-bit errors) will be discarded, unless configured
otherwise by the user.
More specifically, whenever the HEC Byte Verification block detects ANY cells with header byte errors, then it
will do all of the following.
1.
It will generate the “Detection of Uncorrectable HEC Byte Error” Interrupt.
The Receive ATM Cell
Processor block will indicate that it is declaring the “Detection of Uncorrectable HEC Byte Error” Interrupt, by
doing the following.
a.
Toggling the “INT*” output pin “l(fā)ow”.
b.
Setting Bit 2 (Detection of Uncorrectable HEC Byte Error Interrupt Status), within the “Receive ATM
Cell Processor Block – Receive ATM Interrupt Status Register – Byte 0” to “1” as depicted below.
2. It will increment the “Receive ATM Cell Processor Block – Receive ATM Cell with Uncorrectable HEC Byte
Error Count” Registers.
This is a 32-bit RESET-upon-READ register that resides at Address Locations
0xN734 through 0xN737. The bit format of these registers is presented below.
Receive ATM Cell Processor Block – Receive ATM Cells with Uncorrectable HEC Byte Error Count
Register – Byte 3 (Address = 0xN734)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Received Cells with Uncorrectable HEC Byte Error Count[31:24]
RUR
0
Receive ATM Cell Processor Block – Receive ATM Cells with Uncorrectable HEC Byte Error Count
Register – Byte 2 (Address = 0xN735)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Received Cells with Uncorrectable HEC Byte Error Count[23:16]
RUR
0