Rabbit Smartcat, User Manual

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User’s Manual 81
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 BL2100 — 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 BL2100 because the higher
voltage will reduce the backlight service life dramatically.
Figure C-3. LCD/Keypad Module Contrast Adjustment
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 that
was installed at the factory across pins 1–2 on header J5 as shown in Figure C-3. Only one
of these two options is available on these older 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
BL2100. These LCD/keypad modules are no longer being sold.
C2
R2
R1 C3
D2 C1 D1
C5 U2
JP1
R3
U1
C4
C10
CR1
R6
C13
C12
R7
R8
R25
R26
R11
R13 R14
R10 R9 R12
R15
R18
Q8
R16 Q5
R21
Q2
U5
J2
DISPLAY
BOARD
J4
KP1
R17 Q4
R22
Q6
R23
Q7
R20
Q3 R19
U7 C14
R24 C15
C16
U6
U4
C7 C9
U3
LCD1
C11
R4
R5
C6
J1
Q1
J5
C17
RN1
J5
LP3500
2.8 V
OTHER
3.3 V
1
2
3
4
n.c. = 5 V
LCD/Keypad Module Jumper Configurations
Header
Description
Pins
Connected
Factory
Default
J5
2.8 V
3.3 V
5 V
1–2
3–4
n.c.
×
J5
1
2
3
4
Part No. 101-0541
Contrast
Adjustment