Contrast Adjustments For All Boards - Rabbit RabbitCore RCM3209 User Manual

C.2 Contrast Adjustments for All Boards
Starting in 2005, LCD/keypad modules were factory-configured to optimize their contrast
based on the voltage of the system they would be used in. Be sure to select a KDU5V
LCD/keypad module for use with the RCM3000/3100/3200 Prototyping Board — these
modules operate at 5 V. You may adjust the contrast using the potentiometer at R2 as
shown in Figure C-3. LCD/keypad modules configured for 3.3 V should not be used with
the 5 V RCM3000/3100/3200 Prototyping Board because the higher voltage will reduce
the backlight service life dramatically.
Contrast
Adjustment
J5
3
4
Figure C-3. LCD/Keypad Module Voltage Settings
You can set the contrast on the LCD display of pre-2005 LCD/keypad modules by adjust-
ing the potentiometer at R2 or by setting the voltage for 5 V by removing the jumper across
pins 1–2 on header J5 as shown in Figure C-3. Only one of these two options is available
on these LCD/keypad modules.
NOTE: Older LCD/keypad modules that do not have a header at J5 or a contrast adjust-
ment potentiometer at R2 are limited to operate only at 5 V, and will work with the
Prototyping Board. The older LCD/keypad modules are no longer being sold.
User's Manual
Description
Header
2.8 V
J5
3.3 V
5 V
R2
U3
LCD1
Q1
J5
R25
1
R8
R26
2
R11 R13
J5
3 1
Q4 Q6
4 2
OTHER LP3500
3.3 V 2.8 V
n.c. = 5 V
KP1
RN1
C17
Pins
Connected
1–2
3–4
n.c.
D2 C1
D1 JP1
C4
R3
C6
U2 U1
C9 C7 R4
R5
C11
U4
J1
R14 R10 R9 R12
R15
Q7 Q2 Q5
Q8
U5
U6
J2
U7 C14
DISPLAY
J4
Factory
Default
×
CR1
C13
C12
BOARD
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