W83C553F Datasheet, PDF (103/159 Pages) Winbond – SYSTEM I/O CONTROLLER WITH PCI ARBITER

W83C553F
Electrical Specifications
Operational Control Word 1 Register
Function:
The Operational Control Word 1 (OCW1) Register sets and clears the mask bits in the Interrupt Mask
(IMR) Register. Each interrupt request line may be selectively masked or unmasked any time after
initialization.
Type:
Read/Write
Bit Description:
Bits [7:0]:
IMR[7:0]. When a "1" is written to any bit in this register, the corresponding IRQx line is
masked. When a "0" is written to any bit in this register, the corresponding IRQx mask bit is
cleared and interrupt requests will again be accepted by the controller.
Note: Masking IRQ2 on 21h will also mask interrupt requests from A1h, which is physically
cascaded to IRQ2.
WINBOND SYSTEMS LABORATORY
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