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18.1 LCD Controller/Driver Functions
The internal LCD controller/driver of the µ PD780344, 780354, 780344Y, and 780354Y Subseries has the following
functions.
(1) Automatic output of segment signals and common signals by automatically reading display data memory
(2) Internal booster circuit employed for LCD driver reference voltage generator (×3 only).
Therefore, the LCD can be stably displayed even if the supply voltage drops due to a drop in the battery voltage.
In addition, two types of LCD driver reference voltages can be selected by using LCD gain adjust register 0.
(3) Three display modes selectable
• Static (up to 12 lines)
• 1/3 duty (1/3 bias)
• 1/4 duty (1/3 bias)
(4) Four types of frame frequencies selectable in each display mode
(5) Simultaneous driving of static display (up to 12 segments) and dynamic display. The operation mode of the
alternate-function pins (S0 to S11) can be switched between the static display mode and dynamic display mode
in 4-bit units.
(6) Blinking of LCD (only when subsystem clock is used).
Whether each segment blinks or not can be selected.
The blinking cycle can be selected from 0.5 s or 1.0 s.
(7) Operation with subsystem clock
(8) Operating voltage range: 1.8 to 5.5 V
Maximum Number of Segment Signals
40 lines (S0 to S39), of which 12 (S0 to S11) are selectable for static
display, and 28 (S12 to S39) are also used with I/O port lines (P80 to P87,
P90 to P97, P100 to P107, and P110 to P113)
Note The operation mode of the alternate-function pins can be switched between the port mode and segment
signal mode in 1-bit units by using the pin function switching registers (PF8 to PF11).
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CHAPTER 18 LCD CONTROLLER/DRIVER
Table 18-1. Segment Signals and Common Signals
Note
.
User's Manual U15798EJ2V0UD
Common Signals
Dynamic display: COM0 to COM3
Static display: SCOM0
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