Motorola PowerQUICC II MPC8280 Series Reference Manual page 1097

31.10.5.13 AAL1 CES TxBDs
Refer to Section 32.12.2, "AAL1 CES TxBDs
31.10.5.14 AAL2 TxBDs
Refer to Section 33.3.5.5, "SSSAR Transmit Buffer Descriptor."
31.10.5.15 AAL5, AAL1 User-Defined Cell—TxBD Extension
In user-defined cell mode, the AAL5 and AAL1 TxBDs are extended to 32 bytes; see
Figure 31-53.
For AAL0 a complete cell, including the UDC header, is stored
in the buffer; the AAL0 BD size is always 8 bytes.
Offset + 0x08
Used to store the user-defined cell's extra cell header. The extra cell header can be 1–12 bytes long.
Offset + 0x14
Figure 31-53. User-Defined Cell—TxBD Extension
31.10.6 AAL1 Sequence Number (SN) Protection Table
The 32-byte sequence number protection table, pointed to by AAL1_SNPT_BASE in the
ATM parameter RAM, resides in dual-port RAM and is used for AAL1 only. The table
should be initialized according to Figure 31-54.
MOTOROLA Chapter 31. ATM Controller and AAL0, AAL1, and AAL5
Freescale Semiconductor, Inc.
NOTE
Extra Cell Header.
Reserved (12 bytes)
For More Information On This Product,
Go to: www.freescale.com
ATM Memory Structure
31-83