Spectravideo MKI, Сервисное – Техническое руководство

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Ou t p u t
1
( OUT
1 ) ,
P i n 3 4 : Use r-d e s igne d output that can be s e t t o an act ive
low p ro gramm ing b i t 2 ( OUT 1 ) of th e MODEM Con t ro l Reg i s t e r t o a h igh leve l .
The O u t 1 s i gna l i s s e t h i gh up on a M a s t e r R e s e t opera t i on .
C h i p S e l e c t Out ( CSOUT ) , P in 2 4 : When h igh , in d i c a t e s that the c h ip has been
se l e c t e d b y a c t i ve CSO , CS 1 , and CS2 inpu t s . No data t rans f e r c an be ini t i a ted
un t i l t h e CSOUT s i gna l is a l o g ic
1 .
Drive D i s a b l e ( DDI S ) , P i n 23 : Goe s low whe ne ver the CPU i s read ing data f rom
t he INS8 2 50 . A h i gh- le ve l DDIS ou t pu t c an be used to d i s ab l e an e x t erna l
tran s ce i ve r ( i f us ed be tween the CPU and I N S 8 2 50 on the D7 - D o Da t a Bus ) a t
a l l t im e s , except when t he CPU i s r ea d ing da ta .
Baud Out ( BAUDOUT ) , P in 1 5 : 1 6 x c l ock s igna l for the t ransm i t t e r sec t ion o f
t he INS8 2 50 . The c l ock ra t e is e qual to t he ma in re f e rence os c i l l a tor
f re quency d i v ided
the spe c i f ie d d i v i sor in the Baud Gene ra t or D iv i sor
La t ch e s . The BAUDOUT may a l so be used for t he rece iver s e c t i on by t yp ing th i s
ou t p u t t o t h e RCLK input o f t h e c h i p .
In t e r rupt ( INTRP T ) , P in 3 0 : Goes h i gh whe never any one o f the fo l low ing
i n t e r r up t t yp e s ha s an ac t i ve h i gh cond i t i on and is enab l ed v i a the IER!
Re ce iver E r r or F l ag : Rece iver Data Ava i l ab l e : Transm i t t e r H o l d ing Reg i s te r
Empt y ; and MODEM S t a t us . The INTRPT s i gna l i s re s e t l ow upon t h e app rop r i a t e
i n t e rrupt se rvi ce o r a Ma s t e r Re s e t ope r a t i on .
INS8 2 50 L i ne Con t ro l
The s y s t em p rogramme r spe c i f i e s the forma t o f the async h ronous data
c ommun i c a t i o ns exch ange v ia t he L i ne Con t r o l Reg i s t e r . I n a dd i t i on t o
co nt ro l l i ng the forma t , t h e prog ramme r ma y re t r i eve the con t e n t s o f the L ine
Con t r o l Reg i s t er for i n spec t i on . Th i s f e a t u re simp l i f i e s sy s t em p rogramm ing
and e l i m ina t e s the ne ed for separate storage in s y s t em memo ry o f the l i
cha r a c t e r i s t i cs . The contents of t he L i ne Cont ro l Reg i s t er a re indicated i n
tab l e 2 and are descr ibe d be l ow .
B i t s 0 and
1 :
The se two b i t s spe c i f y the numb e r o f b i t s i n each t ransm i t t e d or
rece i ve d s e r i a l characte r . The encod ing of b i t s 0 and
1
is fo l l ows :
B i t
1
B i t 0 Wor d Leng t h
0 0 5 B i t s
0
1
6 B i t s
1
0
7 B i t s
1
1 8 B i t s
4 .59