Tandy 1000 SL Technical Reference Manual page 95

-
I / O
o u t p u t
DESCRIPTION PIN
NAME
CPUCLK
QTY.
1 CPU
c l o c k s i g n a l , 1 2 MHz
50
%
d u t y c y c l e , o r
8
o r
4 MHz
3 3
%
d u t y c y c l e ,
i n t e r n a l l y s w i t c h a b l e .
AQ
-
A l l 1 2 o u t p u t s B u f f
e
r ed b u s a d d r
ess
o u t p u t s , i n t e n d e d t o
d r i v e 5 X T t y p e
1/0
s l o t s , a s
w e l l as
a few
o n b o a r d p e r i p h e r a l s .
E i g h t b i t p e r i p h e r a l d a t a
b u s , i n t e n d e d t o d r i v e 5
XT t y p e 1/0 s l o t s , a s
well
a s a l l on b o a r d
p e r i p h e r a l s .
B i d i r .
IODO
-
I O D 7 8
I ORB 1
o u t p u t CPU/DMA
1/0
Read s i g n a l ,
a c t i v e low. S y s t e m
c o n t r o l l i n e .
I OWB
1 o u t p u t
CPU/DMA
1/0
W r i t e s i g n a l ,
a c t i v e low. S y s t e m
c o n t r o l l i n e .
MEMRB
1 o u t p u t CPU/DMA Memory Read
s i g n a l , a c t i v e l o w .
S y s t e m c o n t r o l l i n e .
MEMWB
1 o u t p u t
CPU/DMA Memory W r i t e
s i g n a l , a c t i v e low.
S y s t e m c o n t r o l l i n e .
M a s t e r
r e s e t
i n p u t ,
s y n c h o n i z e d .
RSTINB
R D Y I N
CPUALE
I n p u t
I n p u t
o u t p u t
U n s y n c h r o n i z e d r e a d y
i n p u t .
C P U A d d r e s s L a t c h E n a b l e .
Decoded f r o m CPU S O
-
S2
when u s e d w i t h C P U
a c c e s s e s . Used t o l a t c h
a d d r e s s e s on t h e
m u l t i p l e x e d a d d r e s s / d a t a
b u s .
BUSALE
1 o u t p u t
DMA
A d d r e s s L a t c h E n a b l e .
G e n e r a t e d by i n t e r n a l
t i m i n g when u s e d w i t h DMA
a c c e s s e s . u s e d t o l a t c h
a d d r e s s e s o n t h e 1/0 b u s .
2