RELEASED
PM73123 AAL1GATOR-8
DATASHEET
PMC-2000097
ISSUE 2
8 LINK CES/DBCES AAL1 SAR
In the sink direction, the UMUX waits until the SNK_INTF FIFO has a cell to
send. Once the SNK_INTF FIFO has a cell to send, the UMUX polls the A1SP
associated with the cell for availability. Once the A1SP has room for the cell, the
UMUX reads the cell out of the SNK_INTF FIFO and places it in the A1SP FIFO.
The UMUX also supports two forms of UTOPIA to UTOPIA loopback; global
loopback, where all cells are looped, and VC based loopback, where only a
specific VC is used to loopback cells. In global loopback all cells received by the
UTOPIA block are sent back out onto the UTOPIA bus. Global loopback is
enabled by setting the U2U_LOOP bit in the UI_COMN_CFG register. In VC
based loopback mode, any cell received with a VC that matches the loopback
VC is sent back out onto the UTOPIA bus. VC based loopback is enabled by
setting the VCI_U2U_LOOP bit in the UI_COMN_CFG register. The loopback
VC is programmable by writing the U2U_LOOP_VCI register. The 3-cell FIFO is
used for loopback.
9.2 AAL1 SAR Processing Block (A1SP)
The A1SP block is the main AAL1 SAR processing block. This block processes
8 E1/T1 lines. This block has the following major components.
• Transmit Frame Transfer Controller (TFTC) block
• Cell Service Decision (CSD) block
• Transmit Adaptation Layer Processor (TALP) block
• TALP FIFO (TFIFO) block
• Local Loopback Block (LOC_LPBK) block
• Receive Frame Transfer Controller (RFTC) block
• Receive Adaptation Layer Processor (RALP) block
• RALP FIFO (RFIFO) block
Figure 6 shows a block diagram of the AAL1gator-8 and the sequence of events
used to segment and reassemble the CBR data.
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