PM73121ꢀAAL1gator II
Data Sheet
PMC-Sierra, Inc.
PMC-980620
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AAL1 SAR Processor
frame completion by writing the line and frame number into a FIFO.
3. The CSD checks a frame-based table for queues having sufficient data to generate a cell. For
each queue with enough data to generate a cell, the CSD schedules the next cell generation
occurrence in the table.
4. The CSD commands the TALP to generate a cell from the available data for each of the ready
queues identified in step 3.
5. The TALP generates the cell from the data and signaling buffers and writes the cell into the
UTOPIA FIFO.
6. The TUTOPIA interface transmits the cells out of the UTOPIA port.
7. The RUTOPIA interface receives the cell from the UTOPIA port.
8. The RALP performs pointer searches, checks for overrun and underrun conditions, detects SN
mismatches, checks for OAM cells, and extracts the line data from the cells, and places the
data into the receive buffer.
9. The RFTC plays the receiver buffer data onto the lines.
10. The MIAC provides arbitration for all memory transaction requests by the various processes.
3.1 Transmit Frame Transfer Controller (TFTC)
The TFTC accepts deframed data from the external T1 or E1 framer device. For structured data,
the TFTC uses the synchronization signals (RL_FSYNC and RL_MSYNC) supplied by the
framer to perform a serial-to-parallel conversion on the incoming data and then places this data
into a multiframe buffer in the order in which it arrives.
A rising edge on RL_FSYNC indicates the beginning of a frame, and a rising edge on RL_
MSYNC indicates the beginning of a multiframe. The TFTC will realign when an edge is seen on
these signals. It is not necessary to provide an edge at the beginning of every frame or multiframe.
The AAL1gator II reads signaling during the last frame of every multiframe. For T1 mode, the
AAL1gator II reads signaling on the 24th frame of the multiframe. For E1 mode, the
AAL1gator II reads signaling on the 16th frame of the multiframe.
A special case of E1 mode exists that permits the use of T1 signaling with E1 framing. Normally
an E1 multiframe consists of 16 frames of 32 timeslots, where signaling changes on multiframe
boundaries. When E1_WITH_T1_SIG is set in LIN_STR_MODE and the line is in E1 mode, the
TFTC will use a multiframe consisting of 24 frames in 32 timeslots. In this mode, the
AAL1gator II reads signaling on the 24th frame of the multiframe.
The AAL1gator II reads the signaling nibble for each channel when it reads the last nibble of each
channel’s data. See Figure 11 on page 26 for an example of a T1 frame. See Figure 12 on page 26
for an example of an E1 frame.
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PMC [ PMC-SIERRA, INC ]
