Control Data Cyber 170 State Hardware Reference Manual page 225

Real-Time Clock Programming
Real-Time Clock Programming
Channel
14
i s reserved f o r t h e real-time clock. This channel, which
i s a l w a y s
8
a c t i v e and f u l l , and may be r e a d a t any time.
The real-time clock i s a 1 2 - b i t ,
free-running counter incrementing a t a 1-MHertz r a t e from 0 through 409510.
Two-Port Multiplexer Programming
NOTE
For two-port m u l t i p l e x e r programming, b i t
numbering w i t h i n words i s 0 through 63 from
l e f t t o r i g h t .
Channel 158
i s
reserved f o r communications with one o r two e x t e r n a l d e v i c e s
through t h e two-port m u l t i p l e x e r . One p o r t i s r e s e r v e d f o r maintenance
purposes, and t h e o t h e r
i s
r e s e r v e d f o r f u t u r e use.
The two-port m u l t i p l e x e r
can communicate with
all
e x t e r n a l d e v i c e s t h a t use EIA s t a n d a r d RS232C s e r i a l
i n t e r f a c e . The m u l t i p l e x e r can accommodate d a t a with odd/even p a r i t y ,
5
to 8
b i t s per c h a r a c t e r and 1 o r 2 s t o p b i t s . I s s u i n g a p p r o p r i a t e f u n c t i o n codes
s e t s t h e format. The r a t e i s switch s e l e c t a b l e f o r each c h a m e l f o r o p e r a t i o n
between Il.0 and 9600 baud. These switches a r e l o c a t e d i n t e r n a l l y on t h e
two-port m u l t i p l e x e r .