SIDE SELECT
The side select function allows you to use double
sided disk drives with your Computer. NOTE: Heath
systems software does not support double-sided
drives at this time. This feature is only provided for
advanced users who wish to implement non-standard
configurations on their own.
This function pulls pin 32 of your H-17 controller
circuit board low (logic 0) whenever a write is per
formed at I/O address 362Q (0F2H) and data bit D6 is
set to a logic 1. This, in turn, selects side 1 of your disk
instead of side 0.
CAUTION: Since the side select function and the
ROM disable use the same port, be careful to preserve
memory status whenever you perform a side select.
You can configure your Computer to use the side
select function in two ways. “Method #1” (preferred)
allows you to use an unused bus line, while “Method
#2” requires a connection to the H-17 controller cir
cuit board. Perform the steps under only one of the
following headings.
Method #1
( ) Position the Extended Configuration Board as
shown in Pictorial 2-6. Then solder a 1" bare
wire between holes AC in the circuit board and
cut off any excess lead lengths.
( ) Remove the tie bracket from your Computer.
( ) Carefully unplug the CPU circuit board from
your Computer.
( ) Refer to Pictorial 2-7 and carefully unsolder or
cut the indicated jumper wire from the CPU
circuit board.
PICTORIAL 2-7
PICTORIAL 2-6
( ) Carefully reinstall the CPU circuit board in your
Computer. Be sure to reconnect the 5-pin socket
from the front circuit board in your Computer.
