Specifications

7.2 EXTERNAL WRITE CURRENT SWITCH
This option permits write current switching via the optional WRITE CURRENT SWITCHING interface line (pin 2).
When the interface signal is activated to a logical zero level. the lower value of the write current is selected. Selec-
ting this option replaces internal write current switching at track
40.
To enable external write current sWitching. move the shorting plug at trace SI to the SE position. See figure 7-3.
+5V
..... STANDARD TRACE
1I1'}II DELETED TRACE
2
.-. ADDED OR JUMPERED
EXTERNAL
WRITE
CURRENT SWITCH -"lfr---- ...
TRACE
TO WRITE
-TRACK 40-- ........... /,.....--+---1"'"----' ~---I CURRENT REF
SI
FIGURE 7·3. EXTERNAL WRITE CURRENT OPTION
7.3 TWO-SIDED STATUS (OPTIONAL OUTPUT SA860 ONLY)
39216·21.
When the drive is selected and the diskette is spinning, this line will indicate a logical zero level for two sided media,
and a logical one for single sided media.
To install this option on a standard drive. jumper trace 25.
7.4 DISK CHANGE (OPTIONAL OUTPUT)
This customer installable option is enabled by jumpering trace DC. When DRIVE SELECT is activated, it will pro-
vide a true signal (logical zero)
onto the interface (pin 12) if. while deselected, the drive has gone from a READY to
a
NOT READY (door open) condition. This line is reset on the true to false transition of DRIVE SELECT if the drive
has gone READY. Timing of this line is illustrated in figure 7-4. The circuitry is illustrated in figure 7-5.
ss
-DRV SEL -----
_
------Irs
-READY .
ss
I
I
-DISK CHG -----J~f"""-- ... S,S~........j
ss
INTERNAL
({
,j
ENABLE
• READY
will not return until two index transitions after DRIVE SELECT (MOTOR ON).
39216·22
FIGURE 7·4. DISK CHANGE TIMING
7-5