A8259 Datasheet, PDF (1/24 Pages) Altera Corporation – PROGRAMMABLE INTERRUPT CONTROLLER

July 1997, ver. 1
Features
General
Description
a8259
Programmable
®
Interrupt Controller
Data Sheet
s Optimized for FLEX^® and MAX^® architectures
s Offers eight levels of individually maskable interrupts
s Expandable to 64 interrupts
s Offers a flexible priority resolution scheme
s Provides programmable interrupt modes and vectors
s Uses approximately 399 logic elements (LEs) in FLEX devices
s Functionally based on the Intel 8259 device, except as noted in the
“Variations & Clarifications” section on page 79
The Altera^® a8259 MegaCore^™ function is a programmable interrupt
controller. The a8259 can be initialized by the microprocessor through
eight data bus lines (din[7..0] and dout[7..0]), and the ncs, nrd, nwr,
int, and ninta control signals. Figure 1 shows the symbol for the a8259.
Figure 1. a8259 Symbol
A8259
nMRST
CLK
nCS
nWR
nRD
A0
INT
nINTA
CASOUT[2..0]
nSP
CAS_EN
CASIN[2..0] DOUT[7..0]
IR[7..0]
nEN
DIN[7..0]
Altera Corporation
57
A-DS-A8259-01