Tandy 1000 SL Technical Reference Manual page 298

( b ) RDCR ( p i n 39)
P u l s e width s e t t i n g t e r m i n a l f o r t h e
RD
o u t p u t p u l s e .
1 1 1
2V, approx.
Y I V V V
-L
RD
p u l s e width
2v, approx.
Write
&
r e a d i n h i b i t
Read
-
( 4 )
Write c i r c u i t
( a ) COMO
( p i n 211, COMl ( p i n 19)
Output t e r m i n a l s o f t h e common d r i v e r . T w o t e r m i n a l s a r e equipped
f o r t h e s i d e 0 and s i d e
1
heads r e s p e c t i v e l y .
Refer t o t a b l e s 202 and 203 a s t o t h e o u t p u t v o l t a g e a t each
o p e r a t i n g c o n d i t i o n .
( b ) EO0 ( p i n 241,
E 0 1
( p i n
2 2 )
Output t e r m i n a l s of t h e e r a s e d r i v e r which i s c o n s t r u c t e d with open
c o l l e c t o r
N P N
t r a n s i s t o r s .
Two
t e r m i n a l s a r e equipped. While t h e
EG
i n p u t t e r m i n a l i s
H I G H
l e v e l , one o f t h e d r i v e r s which i s s e l e c t e d
by t h e i n p u t t e r m i n a l t u r n s on (becomes LOW).
Refer t o Table 203.
( c ) W C S O ( p i n 261, WCSl ( p i n 25)
E x t e r n a l r e s i s t o r t e r m i n a l s f o r s e t t i n g t h e w r i t e c u r r e n t . Following
shows t h e c i r c u i t diagram o f t h e t e r m i n a l . By t h e p u l l up r e s i s t o r s
f o r t h e W C S O and WCS1, t h e w r i t e c u r r e n t i s determined. The c u r r e n t
is c a l c u l a t e d by t h e e x p r e s s i o n i n i t e m 2-2-1-1 ( 2 ) .
-
219
-