w83c553f Winbond Electronics Corp America, w83c553f Datasheet - Page 102

• Manufacturer Part Number: w83c553f
• Description: System I/o Controller With Pci Arbiter
• Manufacturer: Winbond Electronics Corp America

W83C553F
Initialization Command Word 4 Register
Function:
Type:
Bit Description:
WINBOND SYSTEMS LABORATORY
Bits [7:5]:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
Both interrupt controllers must have the Initialization Command Word 4 (ICW4) Register programmed
as part of their initialization sequence. At a minimum, bit 0 must be set to "1" to indicate it is operating
in an x86-based system.
Write Only
Reserved. These bits must be programmed to "000."
SFNM. Special Fully Nested Mode. This mode should normally be disabled by writing "0" to
this bit.
BUF. Buffered Mode. This bit must be programmed to "0" for the W83C553F.
MNS. Master/Slave in Buffered Mode. This bit must be programmed to "0" for the W83C553F.
AEOI. Automatic End of Interrupt. This bit should normally be programmed to "0." If
programmed to "1," Automatic End of Interrupt Mode is enabled.
UPM. Microprocessor Mode. This bit must be set to "1" to indicate the interrupt controller is
operating in an x86-based system.
Electrical Specifications
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