Datasheet

RL78/L12 CHAPTER 14 LCD CONTROLLER/DRIVER
R01UH0330EJ0200 Rev.2.00 658
Dec 13, 2013
14.10.5 Eight-time-slice display example
Figure 14-41 shows how the 15x8 dot LCD panel having the display pattern shown in Figure 14-40 is connected to the
segment signals (SEG4 to SEG18) and the common signals (COM0 to COM7). This example displays data “123” in the
LCD panel. The contents of the display data register (addresses F0404H to F0412H) correspond to this display.
The following description focuses on numeral “3.” ( ) displayed in the first digit. To display “3.” in the LCD panel, it is
necessary to apply the select or deselect voltage to the SEG4 to SEG8 pins according to Table 14-19 at the timing of the
common signals COM0 to COM7; see Figure 14-40 for the relationship between the segment signals and LCD segments.
Table 14-19. Select and Deselect Voltages (COM0 to COM7)
Segment
Common
SEG4 SEG5 SEG6 SEG7 SEG8
COM0 Select Select Select Select Select
COM1 Deselect Select Deselect Deselect Deselect
COM2 Deselect Deselect Select Deselect Deselect
COM3 Deselect Select Deselect Deselect Deselect
COM4 Select Deselect Deselect Deselect Deselect
COM5 Select Deselect Deselect Deselect Select
COM6 Deselect Select Select Select Deselect
COM7 Deselect Deselect Deselect Deselect Deselect
According to Table 14-19, it is determined that the display data register location (F0404H) that corresponds to SEG4
must contain 00110001.
Figure 14-42 shows examples of LCD drive waveforms between the SEG4 signal and each common signal. When the
select voltage is applied to SEG4 at the timing of COM0, a waveform is generated to turn on the corresponding LCD
segment.
Figure 14-40. Eight-Time-Slice LCD Display Pattern and Electrode Connections
COM0
COM1
COM2
COM3
COM4
COM5
COM6
COM7
SSSSS
EEEEE
GGGGG
n+4 n+3 n+2 n+1 n
Remark 30-pin products: n = 4 to 8
44-pin products: n = 4 to 17
48-pin products: n = 4 to 21
52-pin products: n = 4 to 25
64-pin products: n = 4 to 34