Spectravideo SVI 318 Service – Technical Manual page 90

DLAB
A
0 0
0
0
X
0
X
0
X
1
X
1
X
1
X
1
0
1
1 0
Ma s t e r Re s e t ( MR ) , P i n 3 5 :
Rec e i ve r Buf f e r , Transm i t t e r H o l d i ng , and D iv i s o r L a t c h e s ) , and the con t r o l
OUT 1 , OUT 2 , RTS , DTR ) a re a f f e c te d by an a c t i ve MR inpu t .
1 ) .
R e c e i ve r C l ock ( RCLK) , P in 9 :
r e c e i v e r s ec t i on o f t h e ch i p .
S e r ia l Input ( S I N ) , P in 1 0 :
( pe r i phe r a l dev i ce , MODEM , or d a t a s e t ) .
C l e a r t o Send ( CTS ) , P in 3 6 :
who s e c ond i t i on c an b e t e s te d b y t he CPU by rea d ing b i t 4 ( CTS ) o f t h e MODEM
S t a t u s Reg i s t e r .
t he C T S input h a s change d s t a te s ince t he p re v i ous r e a d ing o f t he MODEM S t a t u s
Reg i s t e r .
No t e : Whe neve r the CTS b i t o f t h e MODEM S t a t us Reg i s t e r c ha ng e s s t a t e , an
i n t e rrupt i s gene r a t e d if t he MODEM S t a t u s I n t e r rupt is e nab l e d .
A
A
0 0
0 1
1 0
1
1
0 0
0 1
1
0
1 1
0 0
0 1
When h i g h , c l e a r s a l l t he reg i s t e r s ( e x c e p t the
Th i s input i s
S e r i a l d a t a input f rom t h e commun i c a t i o n s l ink
The CTS s i g na l i s a MODEM con t ro l fun c t i on inpu t
B i t 0 ( DCTS ) o f the MODEM S ta t u s Reg i s t e r i n d i c a t e s whe t h e r
REG I STER
Rece i ver Bu f f e r ( rea d ) , T ra n sm i t t e r
H o l d i ng Reg i s t e r ( wr i t e )
I n t e r r upt E nab l e
I n t e r r up t Iden t i f i ca t i on ( re a d on l y )
L i ne Con t ro l
MODEM Con t ro l
L i ne S t a t u s
MODEr·f S t a t u s
None
Divi s o r L a t c h ( l e a s t s i g n i f i c a n t by t e )
D i v i s o r La tch ( m o s t s i g n i f i c a t n t b y t e )
the
1 6x baud ra t e c l ock f o r the
4 . 57
( Re f e r t o tab l e