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FORM 160.54-M1
ISSUE DATE: 10/25/2019
• CR11 RX2 – COM2 serial port receive data.
• CR16 TX2 – COM2 serial port transmit data.
• CR10 RX5 – COM5 serial port receive data.
• CR9 TX5 – COM5 serial port transmit data.
Display Interface
The graphic screens displayed on the Liquid Crystal
Display are created from the program downloaded
from the Program card and stored in the Flash Memory
Chip. The data to form these screens is output from J5.
This data is in the form of red, green and blue drive
signals applied to each of the 303,200 the display pix-
els arranged in a matrix of 640 columns x 480 rows.
Each pixel consists of 3 windows; red, green and blue,
through which a variable amount of light from the
Display Backlight, is permitted to pass to the front of
the display. The drive signals determine the amount
of light permitted to pass through each window. The
overall pixel color is a result of the gradient of red,
green and blue light allowed to pass. The drive signal
for each pixel is an 18 bit binary word; 6 for each of the
3 colors. The greater the binary value, the more light
is permitted to pass. The pixels are driven sequentially
from left to right, beginning with the top row. To co-
ordinate the drive signals and ensure that the pixels in
each row are driven from left to right and the columns
are driven from top to bottom, the drive signals are ac-
companied by a clock and horizontal and vertical sync
signals.
During the boot-up, the program in the BIOS EPROM
reads wire jumpers PID0 through PID3 on the Display
Interface Board to determine the manufacturer of the
display. Each display manufacturer requires a slightly
different control. The program in the BIOS EPROM
configures the microboard for correct operation for the
actual display installed.
Different display manufacturers require different sup-
ply and control voltages for their displays and back-
lights. Program Jumpers JP2 through JP5 and JP7 and
JP8 must be configured to provide the required sup-
ply and control voltages to the display and backlight
control. SECTION 4 - MICROBOARD 031-02430-000
AND 031-02430-001 lists the required program jumper
configuration for each display. Also, a label attached to
the display mounting plate lists the required program
jumper configuration for that display. The position of
program jumper JP2 determines whether the supply
voltage is +5 VDC or +3.3 VDC.
JOHNSON CONTROLS
The microboard controls the Display Backlight via
J6. The Display Backlight is the light source for the
display. The Backlight Inverter Board provides a high
voltage AC power source for the lamp. It converts low
voltage DC via J6-1 (+12 VDC or +5 VDC, depending
on position of Program Jumper JP5) to high voltage
AC (500 to 1500 VAC). This high voltage AC is ap-
plied to the lamp to cause it to illuminate. The Back-
light is turned ON and OFF with the BACKLIGHT
ENABLE signal (J6-5).
The position of Program Jumper JP4 determines
whether this is a +12 VDC or +5 VDC signal. In some
displays, the backlight turns ON when this signal tran-
sitions from low to high; others turn OFF when it tran-
sitions from high to low.
The position of Program Jumper JP3 determines the
transition that will occur when the microboard outputs
the Backlight Enable signal. Program Jumper JP3 must
be positioned according to the display manufacturer's
requirement.
Under Program control, the microboard controls the
backlight brightness via the Lamp Dimmer circuit out-
put at J6-7. In order to extend the life of the Backlight
lamp, the brightness is driven to 50% after 10 minutes of
Keypad inactivity. At this brightness level, the graphics
are still visible.
When Keypad activity is detected (a key is pressed), the
lamp is driven back to full (100%) brightness. Some dis-
play manufacturers require a variable voltage to vary the
brightness; others require a variable resistance. Program
Jumpers JP7 and JP8 must be configured to enable the
appropriate technique.
JCI COMPANY CONFIDENTIAL
SECTION 3 - MICROBOARD 031-01730-000
3
37
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