Operation; Settings Up To Lcd Display - Hitachi H8S/2646 Hardware Manual

18.3

Operation

18.3.1

Settings up to LCD Display

To perform LCD display, the hardware and software related items described below must first be
determined.
Hardware Settings
• Using 1/2 duty
When 1/2 duty is used, interconnect pins V2 and V3 as shown in figure 18-2.
Figure 18-2 Handling of LCD Drive Power Supply when Using 1/2 Duty
• Panel display
As the impedance of the built-in power supply split-resistance is large, the display may lack
sharpness when driving a panel. In this case, refer to section 18.3.4, 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.
• LCD drive power supply setting
With the H8S/2646 Series, there are two ways of providing LCD power: by using the on-chip
power supply circuit, or by using an external power supply circuit.
When an external power supply circuit is used for the LCD drive power supply, connect the
external power supply to the V1 pin.
LPV
CC
V1
V2
V3
V
SS
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