HD6433802H Datasheet, PDF (322/435 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

13.3 Operation
13.3.1 Settings up to LCD Display
To perform LCD display, the hardware and software related items described below must first be
determined.
1. Hardware settings
a. Using 1/2 duty
When 1/2 duty is used, interconnect pins V₂ and V₃ as shown in figure 13.2.
VCC
V1
V2
V3
VSS
Figure 13.2 Handling of LCD Drive Power Supply when Using 1/2 Duty
b. Large-panel display
As the impedance of the built-in power supply split-resistance is large, it may not be
suitable for driving a large panel. If the display lacks sharpness when using a large panel,
refer to section 13.3.4, Boosting the LCD Drive Power Supply. When static or 1/2 duty is
selected, the common output drive capability can be increased. Set CMX to 1 when
selecting the duty cycle. In this mode, with a static duty cycle pins COM₄ to COM₁ output
the same waveform, and with 1/2 duty the COM₁ waveform is output from pins COM₂ and
COM₁, and the COM₂ waveform is output from pins COM₄ and COM₃.
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