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LCD CONTRAST
Register Address Register
Name Function Read/Write
Control
0x28 (40)
LCDCONTRAST
Define LCD contrast
Write (Read)
Register Size Register
structure Unit
1 Byte
Unsigned Int 8 bits
none
Description:
This value is converted to a voltage which is needed by the LCD for its contrast.
WARNING: HIGH CONTRAST CAN REDUCE THE LIFE OF THE LCD.
To select the contrast of the LCD, begin at 0 and increase it until the visibility is good. If you continue to
increase it, you will not probably see a real difference, but the LCD will not appreciate (after a long
time).Too high levels can be detected after a long use (>1 day) when older characters (image retention)
still appear on the LCD positions filled with blank (space) characters.
Each LCD has an operating voltage pin (Vo) depending of LCD type and temperature.
Typically at 25°C Vo is ~0.5V (Vdd-Vo=4.5v).
Example of
LCDCONTRAST
:
0-127
T°>25°C
128-255
T<25°C
Limits:
Min:
0
~2V (for 50°… 70°)
Max:
255
~0V (for 0 … -20°C)
Default:
127
~0.5V for 25°
Active:
Each time the processor is running
.
FMod-IPAXESCTRL User Manual v.1.1