NH82801DB S L8DE Intel, NH82801DB S L8DE Datasheet - Page 325

• Manufacturer Part Number: NH82801DB S L8DE
• Manufacturer: Intel

Specifications of NH82801DB S L8DE

• Lead Free Status / RoHS Status: Compliant

9.4.1
Intel
®
82801DB ICH4 Datasheet
ICW1—Initialization Command Word 1 Register
Offset Address:
Default Value:
A write to Initialization Command Word 1 starts the interrupt controller initialization sequence,
during which the following occurs:
Once this write occurs, the controller expects writes to ICW2, ICW3, and ICW4 to complete the
initialization sequence.
1. The Interrupt Mask register is cleared.
2. IRQ7 input is assigned priority 7.
3. The slave mode address is set to 7.
4. Special mask mode is cleared and Status Read is set to IRR.
7:5
Bit
4
3
2
1
0
ICW/OCW Select — WO. These bits are MCS-85 specific, and not needed.
000 = Should be programmed to 000
ICW/OCW Select — WO.
1 = This bit must be a 1 to select ICW1 and enable the ICW2, ICW3, and ICW4 sequence.
Edge/Level Bank Select (LTIM) — WO. Disabled. Replaced by the edge/level triggered control
registers (ELCR).
ADI — WO.
0 = Ignored for the Intel
Single or Cascade (SNGL) — WO.
0 = Must be programmed to a 0 to indicate two controllers operating in cascade mode.
ICW4 Write Required (IC4) — WO.
1 = This bit must be programmed to a 1 to indicate that ICW4 needs to be programmed.
Master Controller
Slave Controller
All bits undefined
®
ICH4. Should be programmed to 0.
–
0A0h
–
020h
Description
Attribute:
Size:
LPC Interface Bridge Registers (D31:F0)
WO
8 bit /controller
325