UPD78F1502AGK-GAK-AX Datasheet, PDF (713/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 16 LCD CONTROLLER/DRIVER
16.7.4 Four-time-slice display example
Figure 16-26 shows how the 12-digit LCD panel having the display pattern shown in Figure 16-25 is connected to the
segment signals (SEG0 to SEG23) 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 F0400H to F0417H) 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 SEG12 and SEG13 pins according to Table 16-8 at the timing
of the common signals COM0 to COM3; see Figure 16-25 for the relationship between the segment signals and LCD
segments.
Table 16-8. Select and Deselect Voltages (COM0 to COM3)
Segment
Common
COM0
COM1
COM2
COM3
SEG12
Select
Deselect
Select
Select
SEG13
Select
Select
Select
Select
According to Table 16-8, it is determined that the display data memory location (F040CH) that corresponds to SEG12
must contain 1101.
Figure 16-27 shows examples of LCD drive waveforms between the SEG12 signal and each common signal. When
the select voltage is applied to SEG12 at the timing of COM0, an alternate rectangle waveform, +VLCD/−VLCD, is generated
to turn on the corresponding LCD segment.
Figure 16-25. Four-Time-Slice LCD Display Pattern and Electrode Connections
SEG2n
SEG2n+1
Remark
78K0R/LF3: n = 0 to 14
78K0R/LG3: n = 0 to 19
78K0R/LH3: n = 0 to 26
COM0
COM2
COM1
COM3
R01UH0004EJ0501 Rev.5.01
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Jun 20, 2011