UPD78F0411GA-GAM-AX Datasheet, PDF (398/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 15 LCD CONTROLLER/DRIVER
15.7.2 Two-time-slice display example
Figure 15-14 shows how the 6-digit LCD panel having the display pattern shown in Figure 15-13 is connected to
the segment signals (SEG0 to SEG22) and the common signals (COM0 and COM1) of the 78K0/LC3 chip. This
example displays data "2345.6" in the LCD panel. The contents of the display data memory (FA40H to FA55H)
correspond to this display.
The following description focuses on numeral "3" ( ) displayed in the fourth digit. To display "3" in the LCD panel,
it is necessary to apply the select or deselect voltage to the SEG12 to SEG15 pins according to Table 15-6 at the
timing of the common signals COM0 and COM1; see Figure 15-13 for the relationship between the segment signals
and LCD segments.
Table 15-6. Select and Deselect Voltages (COM0 and COM1)
Segment
Common
COM0
COM1
SEG12
Select
Deselect
SEG13
Select
Select
SEG14 SEG15
Deselect
Select
Deselect
Select
According to Table 15-6, it is determined that the display data memory location (FA4FH) that corresponds to
SEG15 must contain xx10.
Figure 15-15 shows examples of LCD drive waveforms between the SEG15 signal and each common signal.
When the select voltage is applied to SEG15 at the timing of COM1, an alternate rectangle waveform, +VLCD/−VLCD, is
generated to turn on the corresponding LCD segment.
Figure 15-13. Two-Time-Slice LCD Display Pattern and Electrode Connections
SEG4n+2
SEG4n+3
SEG4n+1
SEG4n
COM0
Remark n = 0 to 4
COM1
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User’s Manual U18698EJ1V0UD