Datasheet

RL78/L12 CHAPTER 14 LCD CONTROLLER/DRIVER
R01UH0330EJ0200 Rev.2.00 650
Dec 13, 2013
14.10.3 Three-time-slice display example
Figure 14-34 shows how the 8-digit LCD panel having the display pattern shown in Figure 14-33 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 register (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 14-17 at the timing of the
common signals COM0 to COM2; see Figure 14-33 for the relationship between the segment signals and LCD segments.
Table 14-17. Select and Deselect Voltages (COM0 to COM2)
Segment
Common
SEG6 SEG7 SEG8
COM0 Deselect Select Select
COM1 Select Select Select
COM2 Select Select
−
According to Table 14-17, it is determined that the display data register location (F0406H) that corresponds to SEG6
must contain x110.
Figures 14-35 and 14-36 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, +V
LCD/−VLCD, is generated to turn on the corresponding LCD segment.
Figure 14-33. Three-Time-Slice LCD Display Pattern and Electrode Connections
SEG3n+2 SEG3n
COM0
COM2
SEG
3n+1
COM1
Remark 30-pin products: n = 0 to 3
44-pin products: n = 0 to 6
48-pin products: n = 0 to 7
52-pin products: n = 0 to 9
64-pin products: n = 0 to 12