Freescale Semiconductor MPC8260 - Manual (Page 1131)

Inverse Multiplexing for ATM (IMA)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 33-29
33.4.3.1 IMA Control (IMACNTL)
The fields of the IMACNTL are shown in Figure 33-13 .
Table 33-4 describes the IMACNTL bit fields.
33.4.4 IMA Group Tables
The IMA group tables consist of multiple IMA group structures indexed by group number, which ranges
from 0 to 7. The transmit and receive parameters are located in separate tables. The IMA group transmit
table entries are 16 bytes long. The IMA group receive table entries are 64 bytes long. However, there is
no need to reserve memory space in DPRAM for 8 receive IMA groups if less than 8 IMA groups are
required. To conserve memory space used by these tables, it is best to add groups starting from group
zero. Note also that group number is independent of the assignment of IMA ID.
2
IMAFILLERHD is located at the word which immediately precedes the 128-byte aligned region defined by IMAROOT.
Thus it is located at offset - 0x04 from base of IMAROOT table.
0 1 2 3 4 5 6 7
Field — IRSE IQB DSB — INTQ
Figure 33-13. IMA Control (IMACNTL)
Table 33-4. IMACNTL Field Descriptions
Bits Name Description
0–1 — Reserved
2 IRSE IMA link receive statistics enable. If link receive statistics gathering is disabled, there is no
need to initialize IRLINKSTAT or reserve space for the receive statistics table.
0
Link receive statistics gathering is disabled.
1 Link receive statistics gathering is enabled.
3 IQB Interrupt queue bus. Defines on which bus the IMA interrupt queue is located.
0
On the 60x bus.
1 On the local bus.
4 DSB Data structure bus. Defines on which bus the IMA external structure memory area is
located.
0
On the 60x bus.
1 On the local bus.
5 — Reserved.
6–7 INTQ Number of the ATM interrupt queue dedicated to IMA events. Note that these do not include
ICP cell reception events; the handling of ICP cell reception events is programmed in the
RCT of the ICP channel defined by RICPCH.