Processor Users Manual

29-63 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
29.10.4.2 APC Priority Table
Each PHYÕs APC priority table holds pointers to the APC scheduling table of each priority
level. It resides in the dual-port RAM. The priority table can hold up to eight priority levels.
Table 29-30 shows the structure of a priority table entry.
29.10.4.3 APC Scheduling Tables
The APC uses APC scheduling tables (one table for each priority level) to schedule channel
transmission. A scheduling table is divided into time slots, as shown in Figure 29-39. Each
slot is a half-word entry. Note that the APC scheduling tables should be cleared before the
APC unit is enabled.
Figure 29-39. The APC Scheduling Table Structure
Slot N+1 is used as a control slot, as shown in Figure 29-40.
0x0A LINE_RATE_AB
R
Hword ABR only. The PHY line rate in cells/sec, represented in TM 4.0 ßoating-point
format. User-deÞned.
0xC REAL_TSTP Word Real-time stamp pointer used internally by the APC. Initialize to 0.
0x10 APC_STATE Word Used internally by the APC. Initialize to 0.
1
Offset values are to APCP_BASE+PHY# ´ 32. However, in slave mode, the offset is from APCP_BASE regard-
less of the PHY address.
Table 29-30. APC Priority Table Entry
Offset Name Width Description
0x00 APC_LEVi_BASE Hword APC level i base address. Pointer to the first slot in the APC scheduling table for
level i. Should be half-word aligned. User-deÞned.
0x02 APC_LEVi_END Hword APC level i end address. Pointer to the last slot in the APC scheduling table for
level i. Should be half-word aligned. User-deÞned.
0x04 APC_LEVi_RPTR Hword APC level i real-time/service pointers. APC table pointers used internally by the
APC. Initialize both pointers to APC_LEVi_BASE.
0x06 APC_LEVi_SPTR Hword
Bits 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Field TCTE 000_0000_0000_0000
Figure 29-40. Control Slot
Table 29-29. APC Parameter Table (Continued)
Offset
1
Name Width Description
APC_LEVi_BASE
APC_LEVi_END
Half Word Entry
slot 0 slot 1 slot N
Control
Slot