ACT apricot - Page 208

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DISK DRIVE

Index Index

pulse

which

acts as

the

reference for

the

start

of a track. Short

duration

negative going

pulse

(150 to 350

JLsl,

generated once per

revolution

of

the

disk (i.e. every 100

ms

at

normal

operational speed).

If

the

drive is

not

selected,

the

output

is

held

at

logic high.

Track

00 Active state, logic low.

When

active, indicates

that

the

head

is

positioned

over

Track

o.

If

the

drive is

not

selected,

the

output

is

set

to logic

high

regardless of

the

position

of

the

head.

Read MFM encoded serial

data

stream

from

the

disk.

Data

If

the

drive is

not

selected,

the

output

is forced

to

logic high.

DriVe

Select 0

DriVe

Select 1

Interface Connections (Inputs)

Active state, logic low.

When

active, selects

the

drive for operation,

if

the

drive is configured as

drive

0 by a

switch

at

the

rear of

the

unit.

Active state, logic low.

When

active, selects

the

drive for operation,

if

the

drive

is

configured

as drive 1

by

a

switch

at

the

rear of

the

unit.

Motor

On

Active state, logic low. Hardwired

to

OV

on

the

System

Board.

The

drive

is

configured by a

switch

on

the

underside

of

the

unit

so

that

the

drive

motor

is

switched

on

only

when

a disk is

within

the

drive.

Step A negative going

pulse

generated by

the

disk

drive controller

which

moves

the

read/write

head,

if

the

drive is selected. Each pulse causes

the

head

to

be

moved

to

an

adjacent

track

location,

in

the

direction

specified by

the

direction

input.

continued

....

Table of Contents

Other manuals for ACT apricot

Service Manual305 pages