µPD75304B,75306B,75308B
5.8 LCD CONTROLLER/DRIVER
The µPD75308B has an on-chip display controller which generates segment signals and common signals in
accordance with data in display data memory as well as a segment driver and common driver capable of
directly driving the LCD panel.
The configuration of the LCD controller/driver is shown in Fig. 5-7
The functions of the on-chip LCD controller/driver of the µPD75308B are as follows.
• Display data memory are read automatically through DMA operations and segment signals and common
signals are generated.
• 5 different display modes can be selected.
➀ Static
➁ 1/2 duty (1/2 bias)
➂ 1/3 duty (1/2 bias)
4 1/3 duty (1/3 bias)
➄ 1/4 duty (1/3 bias)
• In each of the display modes, 4 types of frame frequency can be selected.
• The segment signal output is a maximum of 32 segments (S0 to S31) and 4 common outputs (COM0 to
COM3).
• Segment signal outputs (S24 to S27, S28 to S31) are in 4-segment units and they can be switched for use
as output ports (BP0 to BP3, BP4 to BP7).
• Split resistors can be built-in for the LCD driver power supply (mask option).
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•
Conformity to various bias methods and LCD driver voltages is possible.
When the display is OFF, the current flowing to the split resistors is cut.
• Display data memory not used for the display can be used as ordinary data memory.
• Operation by the subsystem clock is also possible.
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30
NEC [ NEC ]
