V I . A D D R E S S I N G
E a c h c h a n n e l o f t h e D S - 1 0 0 0 u s e s 8 c o n s e c u t i v e I / O
a d d r e s s l o c a t i o n s . T h e b a s e a d d r e s s e s a r e i n d e p e n d e n t b u t
m u s t b e g i n o n a n e v e n 8 - b y t e b o u n d a r y ( x x x 0 H - x x x 7 H o r
x x x 8 H - x x x F H ) . T h e n u m b e r s x x x a r e c o n t r o l l e d b y t h e
P r o g r a m m a b l e O p t i o n S e l e c t ( P O S ) a n d a d d r e s s d e c o d e r s t o
p r o v i d e c o m p l e t e 1 6 - b i t a d d r e s s i n g f o r e a c h c h a n n e l . S i x t e e n
c h o i c e s o f b a s e a d d r e s s a r e p r o v i d e d f o r e a c h c h a n n e l a n d
include the eight addresses defined as SERIAL 1 through SERIAL
8 . T h e r e m a i n i n g e i g h t a d d r e s s e s a r e a c o n s t a n t 8 0 0 0 H o f f s e t
from these values. A complete table of available addresses is
g i v e n i n F i g u r e 1 6 . T h e 1 6 5 5 0 u t i l i z e s i t s e i g h t a s s i g n e d
addresses as shown in Figure 2.
V I I . I N T E R R U P T S
T h e D S - 1 0 0 0 i s c a p a b l e o f s u p p o r t i n g f o u r i n t e r r u p t
l e v e l s , I R Q 3 , 4 , 7 a n d 9 . E a c h c h a n n e l m a y s e l e c t a s e p a r a t e
interrupt or one may be shared by both channels. If interrupt
s h a r i n g i s u s e d , t h e i n t e r r u p t p e n d i n g ( I P ) b i t i n t h e
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 s h o u l d b e u s e d t o t e s t f o r
the source of the interrupt.
C A U T I O N :
T o m a i n t a i n c o m p a t i b i l i t y w i t h e a r l i e r p e r s o n a l
c o m p u t e r s y s t e m s , t h e u s e r d e f i n e d o u t p u t , O U T 2, is
used as an external interrupt enable and must be set
a c t i v e f o r i n t e r r u p t s t o b e a c k n o w l e d g e d . O U T 2 is
accessed through the 16550's MODEM control register.
VIII. P R O G R A M M A B L E
O P T I O N S E L E C T
T h e I B M P S / 2 f a m i l y o f c o m p u t e r s u s i n g t h e M i c r o C h a n n e l
b u s s t r u c t u r e u t i l i z e o n b o a r d r e g i s t e r s r e f e r r e d t o a s t h e
P r o g r a m m a b l e O p t i o n S e l e c t ( P O S ) r e g i s t e r s t o h o l d t h e
a d a p t e r ' s c o n f i g u r a t i o n i n f o r m a t i o n . T h e f i r s t t w o P O S
r e g i s t e r s h o l d a u n i q u e a d a p t e r i d e n t i f i c a t i o n n u m b e r t h a t h a s
b e e n i s s u e d t o Q u a T e c h f o r t h e D S - 1 0 0 0 . T h i s n u m b e r i s
d e f i n e d i n h a r d w a r e a n d c a n n o t b e c h a n g e d . T h e s e r e g i s t e r s
are read only.
T h e r e m a i n i n g P O S r e g i s t e r s a r e u s e d f o r a d d r e s s a n d
i n t e r r u p t s e l e c t i o n s . T h e s e r e g i s t e r s a r e p r o g r a m m e d b y t h e
u s e r t h r o u g h t h e I B M i n s t a l l a t i o n u t i l i t y s u p p l i e d w i t h t h e
P S / 2 . T h e s e r e g i s t e r s a r e r e a d / w r i t e b u t s h o u l d n o t b e
w r i t t e n t o b y u s e r s o f t w a r e . T h e b i t d e f i n i t i o n s o f t h e s e
registers are given in Figures 15(a) and 15(b).
iv
Summary of Contents for DS-1000
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