DS33Z11 Maxim Integrated Products, DS33Z11 Datasheet - Page 50

• Manufacturer Part Number: DS33Z11
• Description: Network Controller & Processor ICs Ethernet Mapper Ethe rnet-Serial TDM Ethe
• Manufacturer: Maxim Integrated Products

Specifications of DS33Z11

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.15 BERT
The BERT can be used for generation and detection of BERT patterns. The BERT is a software programmable
test pattern generator and monitor capable of meeting most error performance requirements for digital
transmission equipment. The following restrictions are related to the BERT:
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restored.
The transmit direction generates the programmable test pattern, and inserts the test pattern payload into the data
stream. The receive direction extracts the test pattern payload from the receive data stream, and monitors the test
pattern payload for the programmable test pattern.
BERT Features
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8.15.1 Receive Data Interface
8.15.1.1 Receive Pattern Detection
The Receive BERT receives only the payload data and synchronizes the receive pattern generator to the
incoming pattern. The receive pattern generator is a 32-bit shift register that shifts data from the least significant
bit (LSB) or bit 1 to the most significant bit (MSB) or bit 32. The input to bit 1 is the feedback. For a PRBS pattern
(generating polynomial x
the feedback is bit n. The values for n and y are individually programmable (1 to 32). The output of the receive
pattern generator is the feedback. If QRSS is enabled, the feedback is an XOR of bits 17 and 20, and the output
is forced to one if the next 14 bits are all zeros. QRSS is programmable (on or off). For PRBS and QRSS
patterns, the feedback is forced to one if bits 1 through 31 are all zeros. Depending on the type of pattern
programmed, pattern detection performs either PRBS synchronization or repetitive pattern synchronization.
8.15.1.2 PRBS Synchronization
PRBS synchronization synchronizes the receive pattern generator to the incoming PRBS or QRSS pattern. The
receive pattern generator is synchronized by loading 32 data stream bits into the receive pattern generator, and
then checking the next 32 data stream bits. Synchronization is achieved if all 32 bits match the incoming pattern.
If at least is incoming bits in the current 64-bit window do not match the receive pattern generator, automatic
pattern resynchronization is initiated. Automatic pattern resynchronization can be disabled.
The RDEN and TDEN are inputs that can be used to “gap” bits.
BERT will transmit even when the device is set for X.86 mode and TDEN is configured as an output.
The normal traffic flow is halted while the BERT is in operation.
If the BERT is enabled for a Serial port, it will override the normal connection.
If there is a connection overridden by the BERT, when BERT operation is terminated the normal operation is
PRBS and QRSS patterns of 2
Programmable repetitive pattern. The repetitive pattern length and pattern are programmable
24-bit error count and 32-bit bit count registers
Programmable bit error insertion. Errors can be inserted individually
(length n = 1 to 32 and pattern = 0 to (2
n
+ x
y
+ 1), the feedback is an XOR of bit n and bit y. For a repetitive pattern (length n),
9
-1, 2
15
-1 2
23
-1 and QRSS pattern support
n
– 1)).
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