Spectravideo MKI, Сервисное – Техническое руководство, Страница: 118 / 134

A l s o du r i d ng wr i t e , two a dd i t i o na l s ig na l s a r e p rov i d e d for wri t e p recompen­
sa t i o n . The s e are EARLY ( P i n
1 7 )
and LATE ( P i n
1 8 ) .
EARLY is act i ve t r u e whe n
th e
W D
pu l s e a p p e a r i n g o n ( P in
30)
i s to b e w r i t t e n ea r l y .
LATE
i s ac t ive t rue
whe n t h e WD pu l s e i s to be wr i t t en
LATE . I
f bo t h
EARLY
and
LATE
are l ow whe n
th e
WO
pu l s e i s p re s e n t , t h e
WD
pu l se i s to be w r i t t e n a t nom ina l . S in c e wr i t e
p r e c ompe n s a t i o n va l u e s va ry f rom d i sk ma nu f ac t u re r t o d i sk manu f ac t u re r , the
ac t u a l va l u e is det e rm i n e d by s e ve r a l one sho t s or de l a y l in e s wh ich a r e
loc a t e d exte rna l to t h e FD 1 793 . The wr i t e p re c ompe n s a t i on s i gna l s
EARLY
a n d
LATE
a re v a l i d f o r t he du ra t i on o f
WD
in b o t h
FM
a n d
Mfll
f orma t s .
WR ITE ?RECOMPENSAT ION
Wr i t e p re c ompe n s a t i o n ( wh ich coun t e ra c t s th e ' d r i f t i ng ' when f l ux t ra n s i t i o n s
a re p l a ce d c l o s e toge t h e r o n t he more c r ampe d i n s ide t racks ) i s ava i l ab l e t o
the u s e r on any t rack s th a t he fee l s ne c e s s a ry .
STATUS REGISTER SUMMARY
A LL TYPE
1
READ READ
READ
WRITE
WRITE
B I T COMMANDS
ADDRE S S S ECTOR TRACK SECTOR TRACK
S 7
NOT
R
EADY NOT READY NOT READY NOT READY NOT . READY
NOT READY
S6
WR ITE
0 0 0
WR ITE WRITE
PROTECT PROTECT PROTECT
ss
HEAD LOADED
0
RECORD
0
WR ITE WRITE
TYPE FAULT FAULT
S 4 S EEK ERROR RNF RNF
0
RNF 0
!
S3
CRC ERROR CRC ERROR
CRC ERROR
0
CRC ERROR
0
I
I
S 2 TRACK
0
LOST DATA
LOST DATA
LOST
LOST DATA LOST
DATA DATA
S l INDEX DR
Q
DR
Q
DR
Q
DRQ DR
Q
so
BUSY BUSY BUSY BUSY BUSY
BUSY
4 . 85