
PM5317 SPECTRA-9953 Telecom Standard Product Data Sheet
Release
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000741, Issue 5
119
Code
Group
Name
Curr. RD-
abcdei fghj
Curr. RD+
abcdei fghj
Encoded Signals
Description
Transport frame alignment
K.28.4-
001111 0010
-
IPAIS = ’b1
High-order path AIS
High-Order Path Termination (HPT) Mode
K28.0-
001111 0100
-
IPL = ‘b0
High-order path H3 byte position,
no negative justification event
K28.0+
-
110000 1011
IPL = ‘b0
High-order path PSO byte position,
positive justification event
K28.6
001111 0110
110000 1001
IJ1 = ’b1
IPL = ‘b1
High-order path frame alignment
14.19 Receive 8B/10B TelecomBus Decoder (R8TD)
The Receive 8B/10B TelecomBus Decoder (R8TD) block frames to the receive stream to find
8B/10B character boundaries. It also contains a FIFO to bridge between the timing domain of
the receive LVDS links and the system clock timing domain. A total of 16 R8TD blocks are
instantiated in the SPECTRA-9953 device.
14.19.1
FIFO Buffer
The FIFO buffer sub-block provides isolation between the timing domain of the associated 16
LVDS links and that of the system clock (SYSCLK) . Data with arbitrary alignment to 8B/10B
characters are written into a 10-bit by 24-word deep FIFO at the link clock rate. Data is read
from the FIFO at every SYSCLK cycle.
14.19.2
Frame Counter
The Frame Counter sub-block keeps track of the octet identity of the outgoing data stream. It is
initialized by a delayed version of the AFP signal. It identifies the positive stuff opportunity
(PSO) and negative stuff opportunity (H3) bytes within the transport frame so that high-order
path pointer justification events can be identified and decoded.
14.19.3
Character Alignment
The character alignment sub-block locates character boundaries in the incoming 8B/10B data
stream. The framer logic may be in one of two states, SYNC state and HUNT state. It uses the
8B/10B control character (K28.5) used to encode the SONET/SDH J0 byte to locate character
boundaries and to enter the SYNC state. It monitors the receive data stream for line code
violations (LCV). An LCV is declared when the running disparity of the receive data is not
consistent with the previous character or the data is not one of the characters defined in the
IEEE standard 802.3. Excessive LCVs are used to transition the framer logic to the HUNT
state.