Allen-Bradley 1747-OC Series, User Manual

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1747-UM001A-US-P - March 2000
Defining System Settings 5-5
Defining the interrupts for PC Cards in PCMCIA interface modules
All PC Cards that use interrupts, such as Ethernet cards, use ISA interrupts.
Make sure you define the interrupts as ISA/EISA on the BIOS screen.
Defining interrupts for a 1747-OCKTX, -OCKTXD module
Each channel on a 1747-OCKTX, -OCKTXD module can have an ISA or
PCI interrupt, based on the jumper settings you make (Table 5.C). If you set
the jumpers for ISA interrupts, make sure the IRQs selected by the jumpers
are defined as ISA/EISA in BIOS. If you use ISA interrupts, each channel
must have a unique interrupt. Each ISA interrupt is a unique interrupt that
cannot be used by any other device.
ISA interrupts are edge-level triggered. A high true signal indicates an
interrupt. Multiple devices cannot share an ISA interrupt because another
module on the bus cannot drive the signal high when another module on the
bus is pulling the signal low.
PCI interrupts are low true. The signal is floating high so multiple devices
can pull the signal low, which indicates an interrupt.
The 1747-OCKTX, -OCKTXD module can generate either kind of
interrupt, based on the jumper settings you make. The BIOS configuration
screen for interrupts determines the types of interrupts and whether an
interrupt should pass through the PCI bridge device to convert it to the
correct signal (Figure 5.1).
On the 1747-OCE with AMIBIOS version 1.04 or earlier only: BIOS
assigns a PCI interrupt to the PCMCIA interface module, but the module
never uses that interrupt, so another device can share that interrupt.
On the 1747-OCF and 1747-OCE with AMIBIOS version 1.05 or later:
BIOS does not assign a PCI interrupt to the PCMCIA interface module.
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