MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
44-1
Chapter 44
AAL2 Implementation
44.1
AAL2 Features and Restrictions
Features of the AAL2 implementation are as follows:
•
Implements the ITU I363.2 specification
•
Supports up to 256 AAL2 channels. Channel numbers 0–255 are available for AAL2 or
non-AAL2. Channel numbers greater than 255 can only be used for non-AAL2 channels.
•
Built-in mechanism for Timer CU support without host intervention
•
After the host initializes the AAL0 BDs and buffers associated with the AAL2 channels, AAL2
handles the interface with AAL0 operation.
•
Optional simultaneous use of CPM RISC timers and the Timer CU mechanism
•
Reassembly:
— Sequence number (SN) and parity check for each CPS-Packet
— Length indication (LI) and CRC5 check for each cell
— OSF of the STF check (valid value is less than 48)
•
Segmentation:
— Perform CPS-PDU padding as needed
— Sequence number (SN) and parity generation for each cell
— CRC5 generation for the CPS-PH
The following restrictions apply when AAL2 functionality is enabled:
•
Serial ATM is not available on SCC4. (UTOPIA can still be used.)
•
AAL0 buffers should start on a 64-byte-aligned address.
44.2
Overview of the AAL2 Implementation
AAL2 is implemented according to the ITU I.363.2 specification. The implementation builds upon AAL0
operation and existing data structures, such as connection tables. For each AAL2 channel, data is
converted from AAL2 packets into AAL0 cells and vice versa. After initialization, the AAL0 operation is
transparent to the AAL2 host application.
Summary of Contents for PowerQUICC MPC870
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Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
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Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
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Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...