PM5364 pmc-sierra, PM5364 Datasheet - Page 82

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
In Serial TelecomBus framing mode, the RSEF character alignment block uses the K28.5
control character (identifies the J0 byte) as a search pattern to determine correct byte alignment
from the arbitrarily aligned input data. The character alignment block searches all possible input
bit positions for the search pattern when in the out-of-character-alignment state. The internal
byte alignment boundary is set and the character alignment block changes to the in-character-
alignment state when the character alignment block finds a match to the search pattern. The
character alignment block monitors line-code violations (LCV) reported by the 8B/10B decoder.
The RSEF will enter the out-of-character-alignment state and begin searching for the K28.5
character if five or more line code violations are received within a 15-character window.
Additionally, in this mode, the 8B/10B data stream is decoded into an internal 9-bit bus format
of 8-bits data and 1-bit control (K).
In scrambled framing mode, the RSEF character alignment block transitions from the out-of-
character-alignment state to the in-character-alignment state when three A1 characters followed
by three A2 characters are found. The character alignment block will transition from the in-
character-alignment state to the out-of-character-alignment state when the frame alignment
block transitions to the out-of-frame state.
The frame alignment block synchronizes internal counters to the frame timing of the input data
stream. The frame alignment block outputs an out of frame (OOF) signal that is initially
asserted to indicate the RSEF is not aligned to a frame. The first character alignment will result
in the frame alignment block changing to the hunt state. A single correctly aligned frame must
be received before the frame alignment block de-asserts the OOF signal to indicate an in-frame
condition. Similarly, receiving four improperly aligned frames when in the in-frame condition
will result in the OOF signal being asserted and a return to the initial out-of-frame state. The
frame alignment block processes the character alignment information whenever the frame
alignment block is in the out-of-frame state. The framing block decodes the frame counters to
generate the timing signals used by other blocks within the RSEF.
The 8B/10B decoder decodes according to the IEEE802.3 standard with the exception of special
characters used to encode TelecomBus control signals (the line codes for positive and negative
accumulated disparity of the control characters K28.5, K28.4, K28.6, K28.0, K27.7, K28.7,
K29.7, K30.7, and K23.7). For these special control codes, the RSEF substitutes the decoded
data with an arbitrarily defined value and sets the K control signal high. For all other characters,
with the exception of characters that violate the 8B/10B line code, the RSEF outputs the
decoded 8B/10B data value as defined by the IEEE802.3 specification and sets K low.
The 8B/10B decoder monitors and reports line code violations. A LCV occurs when the
incoming data is not one of the valid 8B/10B characters or when the running disparity is
incorrect. The TelecomBus special characters K28.0-, K28.0+, K28.4-, K28.4+, K27.7-,
K27.7+, K28.7-, K28.7+, K29.7-, K29.7+, K30.7-, and K30.7+ are not considered LCVs but do
affect current running disparity. A maskable interrupt is generated when a line code violation
occurs. The 8B/10B decoder maintains an 8-bit count of the total number of line code violations
when the 8B/10B decoder is enabled. To allow downstream blocks an opportunity to properly
deal with LCVs, characters that generate a LCV are substituted with h0F and K is optionally
asserted high.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
82