Apc Priority Table; Apc Scheduling Tables - Motorola MPC8260 PowerQUICC II User Manual

Part IV. Communications Processor Module
Table 29-29. APC Parameter Table (Continued)
1
Offset Name
0x0A LINE_RATE_AB
R
0xC REAL_TSTP
0x10 APC_STATE
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.

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.
Offset Name
0x00 APC_LEVi_BASE Hword
0x02 APC_LEVi_END
0x04 APC_LEVi_RPTR Hword
0x06 APC_LEVi_SPTR Hword

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.
APC_LEVi_BASE
Figure 29-39. The APC Scheduling Table Structure
Slot N+1 is used as a control slot, as shown in Figure 29-40.
Bits 0 1
Field TCTE
29-63
Width
Hword ABR only. The PHY line rate in cells/sec, represented in TM 4.0 ßoating-point
format. User-deÞned.
Word Real-time stamp pointer used internally by the APC. Initialize to 0.
Word Used internally by the APC. Initialize to 0.
Table 29-30. APC Priority Table Entry
Width
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.
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.
APC level i real-time/service pointers. APC table pointers used internally by the
APC. Initialize both pointers to APC_LEVi_BASE.
slot 0 slot 1
Half Word Entry
2 3 4 5
Figure 29-40. Control Slot
MPC8260 PowerQUICC II UserÕs Manual
Description
Description
APC_LEVi_END
6 7 8 9 10
000_0000_0000_0000
Control
slot N
Slot
11 12 13 14
MOTOROLA
15