DS3181 Maxim Integrated Products, DS3181 Datasheet - Page 158

• Manufacturer Part Number: DS3181
• Description: Network Controller & Processor ICs DS3-E3 ATM-Packet PH Y with Built-in Line
• Manufacturer: Maxim Integrated Products

Specifications of DS3181

• Product: Framer
• Number Of Transceivers: 1
• Data Rate: 44.736 Mbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 280 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: TEBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.8.8 Receive E3 PLCP Frame Processor
The Receive E3 PLCP Frame Processor performs E3 PLCP framing, byte destuffing, performance monitoring and
overhead extraction.
The E3 PLCP frame format is shown in
value of F6h and 28h respectively. P8 – P0 are the Path Overhead Identifier (POI) bytes that indicate the path
overhead byte contained in the current sub-frame. Z3 – Z1 are growth bytes reserved for future use. F1 is the Path
User Channel byte allocated for user communications purposes (This byte is undefined in ATM). B1 is the Bit
Interleaved Parity-8 (BIP-8) byte used for PLCP path error monitoring. G1 is the PLCP Path Status Byte (See
Figure
M2 are the DQDB Layer Management Information bytes used for DQDB layer management communications
(These bytes are undefined in ATM). C1 is the Cycle/Stuff Counter byte used as for PLCP stuff indication.
10.8.8.1 Receive E3 PLCP Framing
E3 PLCP framing determines the E3 PLCP frame boundary. The frame boundary is found by identifying the frame
alignment bytes (A1 & A2), and the path overhead indicator (POI) byte (P#). The framer is an off-line framer that
updates the data path frame counters when an out of frame (OOF) condition is present. The use of an off-line
framer reduces the number of ATM cells discarded during the framing process. The continually searches for two
consecutive sets of alignment bytes (A1 and A2), and two sequential POI bytes (P#) are identified. The data path
frame counters are updated if an OOF condition is present). The maximum average reframe time is 23 µs.
10.8.8.2 Receive E3 PLCP Byte Destuffing
Byte destuffing discards the E3 PLCP frame trailer immediately following sub-frame 0 (POI equals 01h). The trailer
size is determined by the cycle counter byte (C1). The trailer is 17 to 21 bytes. It is 17 bytes if C1 equals 3Bh; 18
bytes if C1 equals 4Fh; 19 bytes if C1 equals 75h; 20 bytes if C1 equals 9Dh; and 21 bytes if C1 equals A7h. The
C1 codes provide error correction capability, and the C1 byte is corrected if required, and then used to determine
the trailer size. Once the trailer size has been determined, the trailer bytes are discarded.
10.8.8.3 Receive E3 PLCP Performance Monitoring
Performance monitoring checks the E3 PLCP frame for errors and alarm conditions. The alarm conditions detected
are OOF, LOF, COFA, and RAI. All alarm conditions are defect conditions. The FEAC Controller does not integrate
alarms for failure conditions.
An Out Of Frame (OOF) condition is declared when an error is detected in both bytes in a framing word (A1 and
A2) or two consecutive POI bytes (P0 - P11) are erred. An OOF condition is terminated when two sequential POI
bytes and two consecutive framing words (A1 and A2) are error free or the E3 PLCP framer updates the data path
frame counters.
If the Loss Of Frame (LOF) integration counter is disabled, an LOF condition is declared when an OOF condition
has been continuously present for 1 ms. If the LOF integration counter is enabled, an LOF condition is declared by
the LOF integration counter when the counter has been active for a total of 1 ms. The LOF integration counter is
active (increments count) when an OOF condition is present, it is inactive (holds count) when an OOF condition is
absent, and it is reset when an OOF condition is continuously absent for 1 ms. An LOF condition is terminated
when an OOF condition is continuously absent for 1 ms.
A Change Of Frame Alignment (COFA) is declared when the E3 PLCP framer updates the data path frame
counters with a frame alignment that is different from the current data path frame alignment.
A Remote Alarm Indication (RAI) condition is declared when ten consecutive frames are received with the RAI bit
(fifth bit of G1) set to one. An RAI condition is terminated when ten consecutive frames are received with the RAI
bit set to zero.
Three types of errors are accumulated: framing errors, BIP-8 errors and Remote Error Indication (REI) errors.
Framing errors are determined by comparing A1, A2, and P# to their expected values. The type of framing errors
accumulated is programmable (OOF, bit, byte, or word). An OOF error increments the count whenever an OOF
condition is first detected (up to 1 per 3 sub-frames). A bit error increments the count once for each bit in A1, each
bit in A2, and each bit in P# that does not match its expected value (up to 24 per sub-frame). A byte error
increments the count once for each A1 byte, A2 byte, and P# byte that does not match its expected value (up to 3
per sub-frame). A word error increments the count once for each frame alignment word (A1, A2, and P#) that does
10-35) used for far-end path status and performance monitoring (bits 6 – 8 are undefined in ATM). M1 and
Figure 10-34.
A1 and A2 are the sub-frame Alignment bytes that have a
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