IBM DS-2000 warranty Functional Description Interrupt Identification Register

FUNCTIONAL DESCRIPTION

B . INTERRUPT

IDENTIFICATION

REGISTER

+------+

D7

FFE

----- FIFO enable (FIFO only)

+------+

D6

0

+------+

D5

0

+------+

D4

0

+------+

D3

IID2

--+

+------+

D2

IID1

+--

Interrupt

identification

+------+

D1

IID0

--+

+------+

D0

IP

-----

Interrupt pending

+------+

F i g u r e 4 .

I n t e r r u p t i d e n t i f i c a t i o n r e g i s t e r b i t

definitions.

FFE

-

FIFO

Enable:

When logic 1, indicates FIFO mode enabled.

IIDx

-

Interrupt

Identification:

Indicates highest priority interrupt pending if

any.

See

IP

and figure

5.

NOTE: IID2

is always

a

logic

0

in

character

mode.

IP

-

Interrupt

Pending:

W h e n l o g i c 0 , i n d i c a t e s t h a t a n i n t e r r u p t i s

p e n d i n g a n d t h e c o n t e n t s o f t h e i n t e r r u p t

identification

register

may

be

used to

determine

the

interrupt

source.

See

IIDx

and

figure 5.

iii