Zenith H-100 - Clock Speed

INTRODUCTION
To permi t the H-207 to operate in many different types of
computers, a number of jumpers and a slide switch are
incorporated into the design of the board. These devices
permit configuring the controller board for the computer
environment in which the H-207 is installed. There are
t h r e e ma ina rea s 0 f con c ern: c10 ck s pee d j urn per i ng ,
selection of interrupt jumpers and the setting of the slide
switch, DS1. Refer to the pictorial on the adjacent page
for the location of the jumpers and the slide switch.
CLOCK SPEED
The host computer clock speed that the H-207 will operate
wi th is determined by the jumpering at J1. As received,
J1 is jumpered by a foil run on the bottom of the board.
(See illustration below.) This jumpering enables the H-207
to operate in computers that have a CPU clock speed faster
than 3 MHz. This jumpering is normal when the H-207 is
installed in a H/Z-100.
FOIL JUMPER
I
5-121
Jl
,
O:':D 0
Jl set for H/Z-IOO Computer operation
or for CPU clock speeds faster than 3 MHz.
For the H-207 to operate in a computer that has a CPU clock
speed at or slower than 3 MHz, the jumpering of J1 must
be al tered. This is accomplished by cutting the foil jumper
on the bottom of the circuit board and installing a 1" wire
jumper from the middle hole of J1 to the rightmost hole.
Refer to the illustration below when performing this
al teration.
CUT FOIL ON BOTTOM OF BOARD
10-82
Jl
Jl setting for 3 MHz or slower CPU
clock speed.