Motorola PowerQUICC II MPC8280 Series Reference Manual page 1202

AAL2 Receiver
Table 33-11. SSSAR RxQD Field Descriptions (continued)
1
Offset Bits Name
0x02 — RxBD Table
Offset
0x04 — RxBD Table
Base
0x08 — —
0x0A — —
0x0C — Time Stamp
0x10 — —
0x12 — —
0x14 — MRBLR
0x16 — Max_SSSAR
_SDU_
Length
0x18– — —
0x1E
1
Boldfaced entries must be initialized by the user.
33.4.4.8 SSSAR Receive Buffer Descriptor
The SSSAR SDU is stored in a BD-buffer structure similar to the structures used for AAL5
frames. The buffer size is determined by SSSAR RxQD[MRBLR]; the actual buffer space
used may be smaller. If the received SSSAR SDU is greater than MRBLR, the SDU spans
over multiple buffers.
The SSSAR RxBD is shown in Figure 33-21.
0 1
Offset + 0x00 E CM
Offset + 0x02
Offset + 0x04
Offset + 0x06
Figure 33-21. SSSAR Receive Buffer Descriptor
33-34
Freescale Semiconductor, Inc.
Points to the next BD to be handled by the CP. The user should initialize this pointer to
zero.
Points to the beginning of the BD table.
Reserved, should be cleared during initialization.
Reserved, should be cleared during initialization.
Used for reassembly timeout of the SSSAR SDU. Whenever the first packet of an
SSSAR SDU arrives the timestamp timer is sampled and stored here (regardless of
the RasT bit).
Reserved, should be cleared during initialization.
Reserved, should be cleared during initialization.
Maximum receive buffer length. Holds the maximum receive buffer length. The actual
buffer size can be less.
Holds the maximum SSSAR SDU length. Upon each new packet the accumulated
frame size is compared with this value. If the limit is exceeded, the CP discards the rest
of the packets of the current frame.
Reserved, should be cleared during initialization.
2 3 4 5 6
W I L RxError
Rx Data Buffer Pointer (RXDBPTR)
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Description
7 10
—
Data Length (DL)
11 15
UUI
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