BASF 6106 - Write Circuits; Write Initiate; Write Logic

2.2.9 WRITE CIRCUITS
2.2.9.1 WRITE INITIATE
The write circuits encade seria1 data from the
host system to magnetic
f1ux patterns recorded
on the F1exy Disk. A write operation is initia-
ted by the host system activating the fo1lowing
input 1ines (see Fig. 2-30).
•
SELECT/
• MOTOR ON/
se1ects the drive and loads
the head
if no head load
option
is instal1ed.
rotates the mini disko
•
WRITE GATE/ turns on the write circuits.
• WRITE DATA/ encoded write data.
•
HEAD LOAD/ loads the head if head load
option
is used.
DC- POWER
MOTOR ON /
0,5 sec HIN ~
I
2.2.9.2 WRITE LOGIC
A simp1ified 10gic of the write circuit is shown
on Fig. 2-31 a. The write circuits are activated
by WRTENA/which is active when the hast system
sends
WRITE GATE. The drive must be se1ected and
the disk not write protected. The data stream fram
the host system is divided by the write flipflop.
It a1ternate1y turns on transistors T3 and T4 (see
Fig. 2-31
b). The write currents I
w
and I
w
' which
are determined by the resistor R 35 flow then
alternately through the windings W
1
and W
2
.
The·write current
and erase current can be b10cked
by the DC-control logic, if apower failure has
been detected. The erase current I
E
is turned on
by transistor T5 when ERASENA/ is low.
DRIVE SELECT/
·(HEAD LOAD/)
SHP I
~ 60 QlSec KIN
...... ~~--~ ..........
WRITE GATEI
WRITE DATA I
35 msec HIN~
HIN ---..l
!
FIGURE 2 - 3D WRITE INITIATE TIMING
2 - 22
8,usec MAX