Disk Controller Configuration Options - NorthStar HORIZON Manual

DISK CONTROLLER CONFIGURATION OPTIONS
ThEre are a number of configuration options possible on the disk
cor troller board that are specified by wiring jumpers on the
boord. The desired configuration should be wired according to
thE following instructions before the board is used.
Jl. Signal grounding. The "G" jumper below location 50 is
normally installed when the disk controller is used in a
HORIZON. If the disk controller is to be used in another S-
100 bus computer, then the "G" jumper should be installed
only if motherboard signal 61 is used as ground in that
computer.
J2
Automatic motor off time. Normally, the disk dr ive motor(s)
will turn off 9.6 seconds after the last disk activity.
I f
some other automatic motor off delay time
1S
desired, then
cut the traces at location 20 on the solder side of the PC
board which connect
itCH
to"2" and "0"
to
" 1.
1
•
Then connect
two jumper Wlres on the component side of the PC board at
location 20 according to the following table:
DELAY TIME FIRST JUMPER
SECONO JUMPER
3.2 seconds
Connect 0 to 3 Connect 2 to 1
6.4 seconds
Connect C to 3 Connect 2 to 1
9 .6 seconds
Connect C to 2
Connect 0 to 1
12.8 seconds Connect B to 3
Connect 2 to 1
16 .0 seconds Connect B to 2
Connect 0 to 1
19. 2 seconds
Connect B to 2
Connect C to 1
25.6 seconds
Connect A to 3 Connect 2 to 1
28.8 seconds Connect A to 2
Connect 0 to 1
32.0 seconds
Connect A to 2 Connect C to 1
38.4 seconds Connect A to 2
Connect B to 1
J3.
6 '-
)
Sector Interrupts. The disk controller board includes logic
which can cause an interrupt to occur each time a sector
hole is detected on a diskette. Normally, this logic is
disabled. To use this logic, first cut the two traces on
the solder side of the PC board near locations 10A and 10B
which connect
.IJ"
to "K
ll
and
"JIl
to
"Ell.
Second, install
two jumper wires on the component side of the PC board which
connect
"SII
to "J"
and
III"
to "K". Third, cut the trace
below location 40 on the solder side of the PC board that
connects My"~ to "PHI". Finally, connect a jumper wire below
location 40 on the component side of the PC board which
connects "Y" to the position for the type of interrupt
desired (VI0/ to PINT/).
North Star HORIZON Computer