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PM73121AAL1gator II
PMC-Sierra, Inc.
L
PMC-980620
,VVXH
AAL1 SAR Processor
Data Sheet
35235,(7$5<$1'&21),'(17,$/7230&6,(55$,1&$1')25,76&86720(56,17(51$/86(
Unstructured data is received without regard to the byte alignment of data within a frame and is
placed in the frame buffer in the order in which it arrives. Figure 13 shows the basic components
of the TFTC.
The receive line interface is primarily a serial-to-parallel converter. Serial data, which is derived
from the RL_SER pin, is supplied to a shift register. The shift register clock is the RL_CLK input
from the external framer. When the data has been properly shifted in, it is transferred to a 2-byte
holding register by an internally derived channel clock. This clock is derived from the line clock
and the framing information.
The channel clock also informs the line-to-memory interface that two data bytes are available
from the line. When the two bytes are available, a line attention signal is sent to the line encoder
block. However, because the channel clock is an asynchronous input to the line-to-memory inter-
face, it is passed through a synchronizer before it is supplied to the line encoder. Since there are
eight potential lines and each of them provides its own channel clock, they are synchronized
before being submitted to the line encoder.
The TFTC accommodates the T1 Super Frame (SF) mode by treating it like the Extended Super
Frame (ESF) format. The TFTC ignores every other frame pulse and captures signaling data only
on the last frame of odd SF multiframes. The formatting of data in the signaling buffers is highly
dependent on the operating mode. Refer to
section 7.6.6 “RESERVED (Transmit Signaling
Buffer)” on page 132
for more information on the transmit signaling buffer.
Figure 13.
Transmit Frame Transfer Controller
External
Framer
External
Framer
Receive Line
Interface
Receive Line
Interface
Line Encoder
Line-to-Memory
Interface
Line Number
Channel Pair Number
Data
16
16
3
4
16
Line 0
Line 0
Line 7
Line 7
ATTN0
ATTN7
DATA0
DATA7
ANY