Functional Operations; Di Rection Select - Spectravideo SVI 318 Service – Technical Manual

SA200 DISK
DRIVE

FUNCTIONAL OPERATIONS

The fo l l ow in g paragraphs d e f i ne th e fun c t i ona l as we l l as the t i m ing re l a t ion­
s h i p s of t he ope r a t ions for t he S A 2 00 .
Power S e quenc ing
App l y ing de p owe r to the SA200 can be done in any se quenc. e .
pow e r- up , t he WR ITE GATE l i ne mu s t be he l d in a c t i ve or a t a h i gh l e ve l .
w i l l p re vent po s s i b l e "g l i t c h i ng" o f the me d i a .
a 3 50 ms d e l a y shou l d be i n t roduced be f o re any o pe r a t i on i s p e r f o rme d .
powe r ing on , in i t i a l po s i t i o n of t h e re a d /w r i t e he a d w i th re s p e c t to the data
t r ack s on t he me d i a c a n be r e a d i n t he header I D f i e l d .
prope r po s i t i oning of the r e a d /wr i t e he a d a f te r powe r i ng on , a step out
o pe r a t i on shou l d be p e r f o rme d unt i l t he TRACK 00 l i ne become s a c t i ve
( re c a l i b r a t e ) .
D r i ve S e l ec t i on
D r i ve se l e c t i on occurs whe n the ap p ro p r i a t e DRIVE SELECT l i ne i s ac t iv a t e d and
t h e p r o p e r se l e c t j umpe r b l ock is i n s t a l l e d .
Mot or On
In o r der for the ho s t s y s t em to re a d o r wr i t e data , the de dr ive motor mus t be
t u rne d on . Th i s i s ac comp l i s he d by a c t iva t ing t he M
de l a y mus t be i n t ro duce d a f t e r ac t i va t i ng th i s l i ne to a l l ow the motor t o come
up to speed be f o re r ea d ing or w r i t ing c an be accomp l i she d .
The mot o r mus t be t u rn e d o f f b y the ho s t s y s t em by deac t iv a t i ng the
l i ne . T h i s shou l d be done i f t he d r i ve ha not r e ce ived a new command w i th in 2
s e c o nd s ( 1 0 re vo l u t i on s o f d i ske t t e ) a f t e r comp l e t i n g the execu t i o n of the las t
command .
T h i s e n s u r e s max imum mot o r and me d i a l i f e _.
T r ack A c c e s s ing
S ee k i ng the re a d /wr i t e he a d f rom one t rack to ano the r is accomp l i sh e d by :
( a ) WR I TE GATE be ing ina c t i ve .
Ac t i va t i ng the DR IVE SE LECT l ine .
( b )
( c ) S e l e c t ing t he de s i re d d i r e c t i on u s ing the
( d ) Pul s i ng the STEP l i ne .
A f t e r app l i ca t i on o f d e powe r ,

DI RECTION SELECT

4 . 89
Howeve r , du r ing
I n order t o a s sure
O O ON
T R l i ne . A 3 50 ms
MOTOR ON
l ine .
Th i s
A f t e r