Motorola MPC8260 User Manual
29-69
MPC8260 PowerQUICC II UserÕs Manual
MOTOROLA
Part IV. Communications Processor Module
29.10.5.3 ATM Controller Buffers
Table 29-34 describes properties of the ATM receive and transmit buffers.
29.10.5.4 AAL5 RxBD
Figure 29-46 shows the AAL5 RxBD.
8
EPD
Early packet discard.
0 Normal operation.
1 AAL5 frames in progress are received, but new AAL5 frames associated with
0 Normal operation.
1 AAL5 frames in progress are received, but new AAL5 frames associated with
this pool are discarded. Can be used to implement EPD under core control.
9Ð15
Ñ
Reserved, should be cleared.
0x0C
Ñ
FBP_ENTRY
Free buffer pool entry. Initialize with the Þrst entry of the free buffer pool. Note
that FBP_ENTRY must be reinitialized when a busy state occurs.
that FBP_ENTRY must be reinitialized when a busy state occurs.
1
Offset from FBT_BASE+RCT[BPOOL]
´ 16
Table 29-34. Receive and Transmit Buffers
AAL
Receive
Transmit
Size
Alignment
Size
Alignment
AAL5 Multiple of 48 octets (except last buffer in frame)
Double word aligned
Any
No requirement
AAL1 At least 47 octets
No requirement
At least 47 octets
No requirement
AAL0 52-64 octets.
Burst-aligned
52Ð64 octets.
No requirement
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Offset + 0x00
E
Ñ
W
I
L
F
CM
Ñ
CLP CNG ABRT CPUU
LNE CRE
Offset + 0x02
Data Length (DL)
Offset + 0x04
Rx Data Buffer Pointer (RXDBPTR)
Offset + 0x06
Figure 29-46. AAL5 RxBD
Table 29-33. Free Buffer Pool Parameter Table (Continued)
Offset
1
Bits
Name
Description