2 end-of-interrupt register, Figure 817. interrupt vector register (slave mode – Intel 80C188XL User Manual

Page 222

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8-27

INTERRUPT CONTROL UNIT

Figure 8-17. Interrupt Vector Register (Slave Mode Only)

8.5.1.2

End-Of-Interrupt Register

The End-of-Interrupt (EOI) register has the same function in Slave mode as in Master mode.
However, non-specific EOI commands are not supported, so the NSPEC bit is omitted from the
register. Only specific EOI commands can be issued. To clear an In-Service bit in Slave mode,
write the three least-significant bits of the interrupt type (from Table 8-5) to the VT2:0 bits.

Register Name:

Interrupt Vector Register (Slave Mode only)

Register Mnemonic:

INTVEC

Register Function:

Specifies the five most-significant bit of the interrupt
vector types for the internal interrupt sources

Bit

Mnemonic

Bit Name

Reset

State

Function

T4:0

Interrupt
Vector Type
Field

00000

Specifies the five most-significant bits of the
interrupt vector types for the internal interrupt
sources. The three least-significant bits are
fixed (see Table 8-5).

NOTE:

Reserved register bits are shown with gray shading. Reserved bits must be written
to a logic zero to ensure compatibility with future Intel products.

A1196-A0

15

0

T
0

T
2

T
1

T
3

T
4

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