Zenith Z-100 PC series Service Manual page 330

POWER ON
~-----------------------~~~~-------------
~
100 ms (MAX)
MOTOR ON
-----t---~~I
____________________
~~----------------
-
\\
DRIVE SELECT
~-~------------~\I~\------------
I
. ...
----....;....--...~1500
ms (MAX)
~ ~2I'S(MAX)
VALID READ DATA
------ I
1.1
m.I(MAXI1
~/I~
_ _ _ _ _ _ _ _ _ _ _..,.
~200I'S(MAX)
_ ___ _
SIDE SELECT
,
~S~------
1ooI'S(MIN)~
~
j.-5oo NS (MIN)
WRITE GATE
}-~-,,\\o\-~/
---+j
(MAXI
r8"
WRITE TRANSITIONS
-------------~~
8I'S(MAX)~
39239-26
FIGURE 1·5. READ TO WRITE (FM)
1.4.8 Read Operation
Reading data from the SA455/465 is accomplished by:
a. Activating the DRIVE SELECT line.
b. Selecting the head.
c. WRITE GATE being inactive.
The timing relationships required to initiate a read sequence are shown in figure 1-5. These timing specifications
are required in order to guarantee that the position of the read/write heads has stabilized prior to reading.
The timing of Read Data (FM) is shown in figure 1-6.
4.0,..s 4.0,..s
NOM N9M
READ DATA - - _ .
I
I I
A
B
A
A B A
39238-05
A
=
LEADING EDGE OF BIT MAY BE ± 800 ns FROM ITS NOMINAL POSITION
B
=
LEADING EDGE OF BIT MAY BE :: 400 ns FROM ITS NOMINAL POSITION
FIGURE 1·6. READ DATA TIMNG (FM)
1·7