ÛZIATECH
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4. INTERRUPT CONTROLLER
The ZT 8907 includes two Intel 8259-compatible cascaded interrupt controllers that
provide a programmable interface between interrupt-generating peripherals and the
CPU. The interrupt controllers monitor 15 interrupts with programmable priority. When
peripherals request service, the interrupt controller interrupts the CPU with a pointer to a
service routine for the highest priority device.
Note:
The ZT 8907 does not support cascaded interrupt controllers on the STD bus.
It may be helpful before reading this chapter to review Chapter 3, "
for a discussion on the STD-80 and STD 32 architectures and their effect on the
operation of the ZT 8907.
The major features of the interrupt architecture are listed below.
•
15 individually maskable interrupts
•
Jumperless configuration
•
Level-triggered or edge-triggered recognition
•
Fixed or rotating priorities
•
PCI Interrupt support
•
PCI Extended Mode register support
The interrupt architecture is shown in the "
" table below. Interrupt
configuration is performed through screen 2 of the BIOS SETUP utility, allowing the
user to set up the interrupt architecture to the needs of the application. The BIOS
SETUP utility allows most of the interrupt controller interrupts to be configured from a
variety of interrupt sources. See the section "
ZT 8907-Specific SETUP Options
" in
Appendix A. The ZT 8907 supports the Extended Mode register, which allows individual
programming of low-level triggered or active high-edge triggered interrupts.