Specifications

+ 5V
o a
Q D--------t
12
C
h..- __ --II..- ... _--*_ -DISK CHG
-READY
-DRVSEL~----------------~------------~~>--------~
39216·23
FIGURE 7·5. DISK CHANGE CIRCUIT
7 _5 SIDE SELECTION USING DIRECTION SELECT (SA860 ONLY)
The SIDE SELECT function can be controlled via the DIRECTION SELECT line, if desired. With this option, the
DIRECTION SELECT line controls the direction of head motion during stepping operations and controls side
(head) selection
during read/write operations. To implement this option, simply move jumper S2 to location Sl.
Figure 7-6 illustrates the circuitry.
+ DRIVE SELECT
S2
-SIDESELECT----~~~----------------1>Cr-~----------1_ __ ~
S1
-01 RECTION SELECT ___ -+- __ ---(~>---------
-SIDE SELECT
FIGURE 7-6. SIDE SELECTION USING DIRECTION SELECT
7.6 SIDE SELECTION USING DRIVE SELECT (SA860 ONLY)
-SIDE 0
CT
-SIDE 1
CT
39216·24
In systems containing no more than two SA860 drives per controller. each read/write head can be assigned a
separate drive address. In such cases, the four DRIVE SELECT lines can be used to select the four read/write
heads. To implement this option, move jumper S2 to S3 and add a jumper to nB (n = 1, 2, 3, or 4). For example,
the first drive may have jumpers installed at DS 1 and 2B while the second drive has jumpers at DS3 and 4B. With
this
jumper configuration installed, the four DRIVE SELECT lines have the following side selection functions:
a. DRIVE SELECT 1 selects side a of first drive.
b. DRIVE
SELECT 2 selects side 1 of first drive
c. DRIVE SELECT 3 selects side a of second drive.
d. DRIVE SELECT 4 selects side 1 of second drive.
Figure 7 -7 illustrates the circuitry.
7-6