LPC/FWH Interface Configuration
11-24
Intel® 460GX Chipset Software Developer’s Manual
11.2.2.9
Elcr1–Edge/Level Control Register (I/O)
I/O Address:
INT CNTRL-1–4D0h
Default Value:
00h
Attribute:
Read/Write
ELCR1 register allows IRQ3 - IRQ7 to be edge or level programmable on an interrupt by interrupt
basis. IRQ0, IRQ1 and IRQ2 are not programmable and are always edge sensitive. When level
triggered, the interrupt is signaled active when input IRQ signal is high.
5
Enable Special Mask Mode (ESMM). 1=Enable SMM bit; 0=Disable SMM bit.
4:3
OCW3 Select. Must be programmed to 01 selecting OCW3.
2
Poll Mode Command. 0=Disable Poll Mode Command. When bit 2=1, the next I/O read to the
interrupt controller is treated as an interrupt acknowledge cycle indicating highest priority
request.
1:0
Register Read Command. Bits [1:0] provide control for reading the In-Service Register (ISR)
and the Interrupt Request Register (IRR). When bit 1=0, bit 0 does not affect the register read
selection. When bit 1=1, bit 0 selects the register status returned following an OCW3 read. If bit
0=0, the IRR will be read. If bit 0=1, the ISR will be read. Following ICW initialization, the
default OCW3 port address read will be “read IRR”. To retain the current selection (read ISR or
read IRR), always write a 0 to bit 1 when programming this register. The selected register can
be read repeatedly without reprogramming OCW3. To select a new status register, OCW3
must be reprogrammed prior to attempting the read.
Bit[1:0] Function
00 No Action
01 No Action
10 Read IRQ Register
11 Read IS Register
Bit
Description
Bit
Description
7
IRQ7 ECL. 0 = Edge Triggered mode; 1 = Level Triggered mode.
6
IRQ6 ECL. 0 = Edge Triggered mode; 1 = Level Triggered mode.
5
IRQ5 ECL. 0 = Edge Triggered mode; 1 = Level Triggered mode.
4
IRQ4 ECL. 0 = Edge Triggered mode; 1 = Level Triggered mode.
3
IRQ3 ECL. 0 = Edge Triggered mode; 1 = Level Triggered mode.
2:0
Reserved. Must be 0.
Summary of Contents for 460GX
Page 1: ...Intel 460GX Chipset System Software Developer s Manual June 2001 Document Number 248704 001 ...
Page 20: ...Introduction 1 8 Intel 460GX Chipset Software Developer s Manual ...
Page 80: ...System Architecture 3 8 Intel 460GX Chipset Software Developer s Manual ...
Page 90: ...System Address Map 4 10 Intel 460GX Chipset Software Developer s Manual ...
Page 98: ...Memory Subsystem 5 8 Intel 460GX Chipset Software Developer s Manual ...
Page 146: ...AGP Subsystem 7 16 Intel 460GX Chipset Software Developer s Manual ...
Page 170: ...IFB Register Mapping 9 6 Intel 460GX Chipset Software Developer s Manual ...
Page 190: ...IFB Usage Considerations 10 20 Intel 460GX Chipset Software Developer s Manual ...
Page 232: ...LPC FWH Interface Configuration 11 42 Intel 460GX Chipset Software Developer s Manual ...
Page 244: ...IDE Configuration 12 12 Intel 460GX Chipset Software Developer s Manual ...
Page 258: ...Universal Serial Bus USB Configuration 13 14 Intel 460GX Chipset Software Developer s Manual ...
Page 270: ...SM Bus Controller Configuration 14 12 Intel 460GX Chipset Software Developer s Manual ...
Page 288: ...PCI LPC Bridge Description 15 18 Intel 460GX Chipset Software Developer s Manual ...
Page 294: ...IFB Power Management 16 6 Intel 460GX Chipset Software Developer s Manual ...