CHAPTER 3 LCD CONTROLLER/DRIVER
User’s Manual U18438EJ2V0UD
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3.8.4 Four-time-slice display example
Figure 3-23 shows how the 12-digit LCD panel having the display pattern shown in Figure 3-22 is connected to the
segment signals (S0 to S23) and the common signals (COM0 to COM3). This example displays data
"123456.789012" in the LCD panel. The contents of the display data memory (addresses 00H to 17H of LCDSEG)
correspond to this display.
The following description focuses on numeral "6." ( ) displayed in the seventh digit. To display "6." in the LCD
panel, it is necessary to apply the select or deselect voltage to the S12 and S13 pins according to Table 3-9 at the
timing of the common signals COM0 to COM3; see Figure 3-22 for the relationship between the segment signals and
LCD segments.
Table 3-9. Select and Deselect Voltages (COM0 to COM3)
Segment S12
S13
Common
COM0 Select
Select
COM1 Deselect
Select
COM2 Select
Select
COM3 Select
Select
According to Table 3-9, it is determined that the display data memory location (0CH of LCDSEG) that corresponds
to S12 must contain 1101.
Figure 3-24 shows examples of LCD drive waveforms between the S12 signal and each common signal. When
the select voltage is applied to S12 at the timing of COM0, an alternate rectangle waveform, +V
LCD
/
−
V
LCD
, is generated
to turn on the corresponding LCD segment.
Figure 3-22. Four-Time-Slice LCD Display Pattern and Electrode Connections
COM0
COM1
COM2
COM3
S
2n
S
2n+1
Remark
n = 0 to 11