2-50
Functional Description
6.
When using polled interrupts go back to step 1 before leaving the
interrupt service routine in case any stacked interrupts moved in
when the first interrupt was cleared. When using hardware interrupts,
the INTA/ (or INTB/) pin is asserted again if there are any stacked
interrupts. This should cause the system to re-enter the interrupt
service routine.
2.2.17 Interrupt Routing
This section documents the recommended approach to RAID ready
interrupt routing for the LSI53C896. In order to be compatible with AMI
RAID upgrade products and the LSI53C896, the following requirements
must be met:
•
When a RAID upgrade card is installed in the upgrade slot, interrupts
from the mainboard SCSI controller(s) assigned to the RAID upgrade
card must be routed to INTC/ and INTD/ of the upgrade slot and
isolated from the mainboard interrupt controller. The system
processor must not see interrupts from the SCSI controllers that are
to be serviced by the RAID upgrade card. An upgrade slot is one that
is connected to the interrupt routing logic for mainboard SCSI
device(s). When a PCI RAID upgrade board is installed into the
system, it would be plugged into this slot if it is to control mainboard
SCSI device(s).
•
The TDI pin of the upgrade slot must be connected to the INT_DIR/
pin of the LSI53C896.
•
When a RAID upgrade card is not installed, interrupts from a SCSI
core must not be presented to the system’s interrupt controller using
multiple interrupt inputs.
shows an example configuration. In this example the
LSI53C896 Dual Channel Ultra2 SCSI Controller contains the interrupt
routing logic.
The LSI53C896 supports four different interrupt routing modes.
Additional information for these modes may be found in register 0x4D,
description in
Each
SCSI core within the chip may be configured independently. The interrupt
routing mode is selected using bits [1:0] in the STEST1 register within
each core. Mode 0 is the default mode and is compatible with AMI RAID
upgrade products.
*
Summary of Contents for LSI53C896
Page 6: ...vi Preface...
Page 16: ...xvi Contents...
Page 88: ...2 62 Functional Description...
Page 112: ...3 24 Signal Descriptions...
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Page 310: ...6 42 Specifications This page intentionally left blank...
Page 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Page 340: ...6 72 Specifications...
Page 346: ...A 6 Register Summary...
Page 362: ...IX 12 Index...