![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT94L33IB-L_datasheet_100163/XRT94L33IB-L_359.png)
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XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
359
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It will increment the “Receive STS-3 Transport B1 Byte Error Count” registers. The “Receive
STS-3 Transport B1 Error Count” register is actually a 32 bit register that resides at Address
Locations = 0x1110 through 0x1113.
The Receive STS-3 TOH Processor block will increment these registers either by the number of erred STS-3
frames detected, or by the number of B1 bits that are detected to be in error (within a given STS-3 frame),
depending upon user selection, as described below.
2.3.1.11.1
Configuring the Receive STS-3 TOH Processor block to increment the “Receive STS-3
Transport B1 Byte Error Count” Registers on a “per-Frame” basis.
The user can configure the Receive STS-3 TOH Processor block to increment the “Receive STS-3 Transport
B1 Byte Error Count” Register, by the value “1” for each STS-3 frame that it determines to have at least one
bit-error within the B1 byte.
The user can accomplish this by setting Bit 0 (B1 Byte Error Type), within the “Receive STS-3 Transport
Control Register – Byte 0” to “1”, as illustrated below.
Receive STS-3 Transport Control Register – Byte 0 (Address = 0x1103)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
SF Detect
Enable
SD Detect
Enable
Descramble
Disable
SDH/SONET*
REI-L Error
Type
B2 Byte
Error Type
B1 Byte
Error Type
R/O
R/W
0
1
2.3.1.11.2
Configuring the Receive STS-3 TOH Processor block to increment the “Receive STS-3
Transport B1 Error Count” register on a “per B1 bit error” basis.
The user can configure the Receive STS-3 TOH Processor block to increment the “Receive STS-3 Transport
B1 Error Count” register by the number of B1 bits, which are determined to be in error. Therefore, in this
mode, it is possible for the Receive STS-3 TOH Processor block to increment this register by as much as the
value of “8” per STS-3 frame.
The user can accomplish this by setting Bit 0 (B1 Byte Error Type) within the “Receive STS-3 Transport
Control Register – Byte 0” to “0”, as illustrated below.
Receive STS-3 Transport Control Register – Byte 0 (Address = 0x1103)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
SF Detect
Enable
SD Detect
Enable
Descramble
Disable
SDH/SONET*
REI-L Error
Type
B2 Byte
Error Type
B1 Byte
Error Type
R/O
R/W
0
2.3.1.11.3
B1 Byte Performance Monitoring
2.3.1.12
LINE BIP-8 (B2) BYTE VERIFICATION
The Receive STS-3 TOH Processor Block has the responsibility for computing and verifying the Line BIP-8
(e.g., B2) byte within each incoming STS-3 frame. When the Receive STS-3 TOH Processor block executes
this function, it will do the following.
It will read in the contents of a given “newly received” STS-3 frame.
It will compute the BIP-8 value over the LOH (Line Overhead) and the Envelope Capacity, within this
STS-3 frame.