CP2400 SILABS [Silicon Laboratories], CP2400 Datasheet - Page 85

• Manufacturer Part Number: CP2400
• Description: 128/64 SEGMENT LCD DRIVER
• Manufacturer: SILABS [Silicon Laboratories]

12.3. LCD Bias Generation and Contrast Adjustment
The LCD Bias voltages are generated using the on-chip charge pump with programmable output voltage. The
programmable output voltage allows software contrast control in 60 mV steps from 2.6 to 3.44 V. The LCD contrast
is controlled by the CONTRAST register.
Note: An external 4.7 µF decoupling capacitor is required (10 µF recommended) on the CAP pin to create a charge reservoir
Intermediate voltages used for 1/2 and 3/4 bias configurations are generated on-chip using a novel approach that
allows driving extra large LCD segments while maintaining ultra low power consumption. This eliminates the need
for off-chip biasing when driving a large LCD. The LCD drive capability can be set using the LCD0PWR register.
The highest power setting should be used for extra large LCDs (which require charging the largest capacitance)
and the lowest power setting should be used with small LCDs (smaller than 1 inch).
SFR Definition 12.2. CONTRAST: Contrast Adjustment
Address = 0x96
Name
Reset
Type
7:4
3:0
Bit
Bit
at the output of the charge pump.
CNTRST Contrast Adjustment.
Unused
Name
R/W
7
0
Read = 0000. Write = Don’t Care.
Selects the on-chip charge pump output voltage.
0000: 2.60 V
0001: 2.60 V
0010: 2.66 V
0011: 2.72 V
0100: 2.78 V
0101: 2.84 V
0110: 2.90 V
0111: 2.96 V
1000: 3.02 V
1001: 3.08 V
1010: 3.14 V
1011: 3.20 V
1100: 3.26 V
1101: 3.32 V
1110: 3.38 V
1111: 3.44 V
R/W
6
0
R/W
5
0
Rev. 1.0
R/W
4
0
Function
3
0
2
0
CNTRST
CP2400/1/2/3
R/W
1
0
0
0
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