Manual

User’s Manual
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: [phone] • www.seetron.com
BPI-216 • v1.2 • 07/00 • pg 2
Location of Connectors and Controls
Figure 1 shows the major features and configuration options of the BPI-216 circuit board. Note: The
Backlight switch has no effect on non-backlit models. The model (-L for backlit, -N for non-) is marked
at the lower-left corner of the interface board.
Figure 1. Back (interface-side) view of BPI-216.
Do not reverse +5V and GND, even momentarily. Reversed power will destroy the electronics.
Do not exceed 5.5V into +5V. Overvoltage will damage the unit or shorten its life.
Quick Checkout and Contrast Adjustment
You can test the unit for proper operation without a computer/serial port. Temporarily connect the
serial input to one of the +5 terminals of J1, then connect power to +5 and GND. The LCD will display
a test message.
The contrast control is usually set fully clockwise at the factory. This setting may be too dark. Use a
small, flat-blade screwdriver to adjust the contrast control.
+5V
Serial data
GND
Duplicate +5V and GND
connections (see text)
BACKLIGHT switch
(down = off; up = on)
BPS switch
(down = 2400; up = 9600)
Contrast
(darker)
Model
N[x] = non-backlit
L[x] = LED backlit
(backlit shown)
Back of LCD
Module
EXTERNAL Backlight switch
(see figure 2 for details)
LED Backlight
On models equipped with an LED backlight (marked L[x] in the lower left corner of the interface board),
you may turn on the backlight by setting the BL switch ON. The backlight will be on whenever power
is applied. There is also a pair of solder pads near the backlight switch (see figure 1 above) to allow
you to control the backlight with an external switch or circuit. Figure 2 below shows the wiring of the
backlight and the pads.
Figure 2. Connecting
external circuits to
control the backlight.
Pads on pcb
(close up section of
fig. 1 above)
Equivalent Circuit
pad 2
pad 1
LEDs
(Vforward≈ 4V)
27Ω
+5V
BL
switch
Applications
press-to-light
pushbutton
(Built-in BL switch must be OFF)
1
2
1
2
NPN
470–
1k
control with
5V logic (1=ON)
1 2
1 2