Motorola MPC8260 User Manual

29-19

MOTOROLA

Channel one in the RCT is reserved as a raw cell queue. The user should program channel
one to operate in AAL0 protocol. The receive raw cell queue is used for removing
management cells from the regular cell ßow to the host. When a management cell is sent to
the receive raw cell queue, the CP sets RxBD[OAM]. The ALL0 BD speciÞes the channel
code associated with the current OAM cell.

The following are optionally removed from the regular ßow and sent to the raw cell queue:

¥

Segment F5 OAM (PTI = 0b100). To enable F5 segment Þltering, set RCT[SEGF].

¥

End-to-end F5 OAM (PTI = 0b101). To enable F5 end-to-end Þltering, set 
RCT[ENDF].

¥

RM cells (PTI = 0b110). When ABR ßow is enabled the cells are terminated 
internally; otherwise, they are sent to the raw cell queue.

¥

Reserved PTI value (PTI = 0b111). Always sent to the raw cell queue.

¥

VCI value: 3, 4, 6, 7Ð15. To enable VCI Þltering set the associated bit in the VCIF 
entry in the parameter RAM.

Figure 29-9 shows a ßowchart of the ATM cell ßow.

Note that even reserved VCI channels should appear in the CAM or address compression
tables; otherwise, a cell on a reserved channel will be considered misinserted.

No

PTI=1xx or

VCI=3,4,6,7-15

and filter enable

Yes

Check

address

No

Match

Yes

Discard

cell

Send cell to VC 

queue

Send cell to raw

cell queue