UPD78F1502AGK-GAK-AX Datasheet, PDF (709/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 16 LCD CONTROLLER/DRIVER
16.7.3 Three-time-slice display example
Figure 16-22 shows how the 8-digit LCD panel having the display pattern shown in Figure 16-21 is connected to the
segment signals (SEG0 to SEG23) and the common signals (COM0 to COM2). This example displays data "123456.78"
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 third digit. To display "6." in the LCD panel, it
is necessary to apply the select or deselect voltage to the SEG6 to SEG8 pins according to Table 16-7 at the timing of the
common signals COM0 to COM2; see Figure 16-21 for the relationship between the segment signals and LCD segments.
Table 16-7. Select and Deselect Voltages (COM0 to COM2)
Segment
Common
COM0
COM1
COM2
SEG6
Deselect
Select
Select
SEG7
Select
Select
Select
SEG8
Select
Select
−
According to Table 16-7, it is determined that the display data memory location (F0406H) that corresponds to SEG6
must contain x110.
Figures 16-23 and 16-24 show examples of LCD drive waveforms between the SEG6 signal and each common signal
in the 1/2 and 1/3 bias methods, respectively. When the select voltage is applied to SEG6 at the timing of COM1 or COM2,
an alternate rectangle waveform, +VLCD/−VLCD, is generated to turn on the corresponding LCD segment.
Figure 16-21. Three-Time-Slice LCD Display Pattern and Electrode Connections
SEG3n+1
COM0
SEG3n+2
SEG3n
COM1
Remark
78K0R/LF3: n = 0 to 9
78K0R/LG3: n = 0 to 12
78K0R/LH3: n = 0 to 17
COM2
R01UH0004EJ0501 Rev.5.01
693
Jun 20, 2011