Sharp FDD-412A - Page 28

FDD412A/B
1
WRITE DATA-N UJ Lf i LI |
Waveshape-arrer if ne = toe
conversion
Fig.
2.19
Write
Pattern
Generation
(in
MFM
Mode)
(b) ERASE GATE generation
To use the erase gate system, the erase head starts operating
a little later than the read/write head.
WRITE GATE-N et ee OO
\ i
|
ERASE GATE-N |
1
saa aa — 580 us max.7—
200
us
TYP
Fig. 2.20 ERASE GATE Generation
2.5.5 Data Read Operation
(1) Interface signals
Table 2.12 Data Read Interface Signals
LOW CURRENT-N| Switches read amplifier filter Same as the one
levels between outer and inner used in write
tracks. operation.
Tracks 0%43 : 'H' level :
Tracks 4446: 'L' level
MFM GATE-N FM/MFM switch signal Required for
FM mode : 'H' level model A FDD alone
MFM mode: 'L' level (with VFO).
VFO SYNC-N Instructs the VFO circuit to
operate, going to 'L’ level in
data read operation.
DATA AREA-N Goes to 'L' level in reading the
data part, during which time the
VFO is held in synchronization.