20-101-1051 Datasheet, PDF (111/165 Pages) List of Unclassifed Manufacturers – C-Programmable Core Module with NAND Flash Mass Storage and Ethernet

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 KDU3V
LCD/keypad module for use with the Prototyping Board for the RCM3365/RCM3375 —
these modules operate at 3.3 V. You may adjust the contrast using the potentiometer at R2
as shown in Figure C-3. LCD/keypad modules configured for 5 V may be used with the
3.3 V Prototyping Board, but the backlight will be dim.
LCD/Keypad Module Jumper Configurations
Header
Description
2.8 V
Pins
Connected
1–2
Factory
Default
×
J5
3.3 V
3–4
5V
n.c.
Contrast
Adjustment
J5
3
1
4
2
R2
U3
LCD1
Q1
J5
R25
R8
R26
D2 C1 D1
C6
C9 C7
R4
R5
C11
JP1
U2
R3
C4
U1
C13
U4
CR1
C12
J1
R11 R13
J5
3
1
4
2
Q4
Q6
OTHER LP3500
3.3 V 2.8 V
n.c. = 5 V
KP1
R14
R10
Q7
U6
U7 C14
R9
R12
R15
Q2 Q5
U5
Q8
J2
C17
RN1
J4
DISPLAY
BOARD
Figure C-3. LCD/Keypad Module Contrast Adjustments
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 3.3 V by connecting the jumper
across pins 3–4 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 not work with the
Prototyping Board for the RCM3365/RCM3375. The older LCD/keypad modules are
no longer being sold.
User’s Manual
105