Sharp MZ-80SFD Manual de usuario descargar pdf (Pagina 6)

® Write data signal

This signal

is

used

to

write

in

data

on

the

diskette.

Each time changing high levels

to

low levels,

the

current flowing in

the

R/W head

is

reversed

to

write

in

data

bit.

This write-in performance

is

available when write

gate signal

is

at

low levels.

@ Write gate signal

This signal being

at

low levels,

data

can be written

on

the

diskette.

At

high levels, read-out

or

sequential

operation

may be made.

(j) Side 1 select signal

This signal

is

given

to

decide which side

of

a

double-face

diskette

to

read

or

write. The R/W

head

of

side 0 and

that

of

side 1 are selected

at

high levels and low levels, respectively.

(2)

Output

signals

There are

the

following four kinds

of

output

signal.

CD

Index signal

By

this signal the. starting position

of

each track

can

be detected. Each time

the

index hole

of

diskette

is

detected

with

the

detector,

the

track

is

fed from

the

drive unit.

Usually, this signal level becomes low each time

the hole

is

detected

at

high levels. Therefore, the

leading edge

of

the

signal indicates

the

beginning

of

a track.

@Track

00

signal

The low-level state

of

this signal signifies

that

the

R/W

head

is

located

at

track

00

position (the

outermost trackJ.

In

any position

other

than

track

~O,

the

signal

is

at

high levels.

When

the R/W head

is

at

track

00,

the head

is

held

at

the position by

the

stopper even

if

another

signal

to

step

outside

is

given. At this time,

however,

the

track

00

signal level becomes high.

By adding still

another

signal

to

step outside,

the

motor phase

is

returned

to

cause track

00

signal

to

become low.

-4-

@ Write protect signal

This signal

is

used

to

detect

whether

or

not

write

protect for the diskette

is

provided. When a

diskette with write

protect

is

in,

the

signal level

becomes low.

In

usual operation, a diskette with write protect

enables to protect write statement within

the

drive.

~

Read data signal

The signal

is

given

to

transfer

data

read from the

diskette.

Usually it

is

at

high levels, while during

detection it comes

down

to

low levels.

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