82374EB Datasheet, PDF (157/208 Pages) Intel Corporation – SYSTEM COMPONENT (ESC)

82374EB 82374SB
Port
020h
021h
021h
021h
021h
4D0h
0A0h
0A1h
0A1h
0A1h
4D1h
0A1h
Table 26 Suggested Default Values For Interrupt Controller Registers
Value
Description of Contents
11h
CNTLR-1 ICW1
08h
CNTLR-1 ICW2 Vector Address for 000020h
04h
CNTLR-1 ICW3 Indicates Slave Connection
01h
CNTLR-1 ICW4 8086 Mode
B8h
CNTLR-1 Interrupt Mask (may vary)
00h
CNTLR-1 Edge Level Control Register
11h
CNTLR-2 ICW1
70h
CNTLR-2 ICW2 Vector Address for 0001C0h
02h
CNTLR-2 ICW3 Indicates Slave ID
01h
CNTLR-2 ICW4 8086 Mode
00h
CNTLR-2 Edge Level Control Register
BDh
CNTLR-2 Interrupt Mask (may vary)
Figure 20 illustrates the sequence software must follow to load the interrupt controller Initialization Command
Words (ICWs) The sequence must be executed for CNTRL-1 and CNTRL-2 After writing ICW1 ICW2 ICW3
and ICW4 must be written in order Any divergence from this sequence such as an attempt to program an
OCW will result in improper initialization of the interrupt controller and unexpected erratic system behavior It
is suggested that CNTRL-2 be initialized first followed by CNTRL-1
In the ESC it is required that all four Initialization Command Words (ICWs) be initialized As shown in Figure
20 all ICWs must be programmed prior to programming the OCWs
157