Datasheet

RL78/L12 CHAPTER 14 LCD CONTROLLER/DRIVER
R01UH0330EJ0200 Rev.2.00 654
Dec 13, 2013
14.10.4 Four-time-slice display example
Figure 14-38 shows how the 12-digit LCD panel having the display pattern shown in Figure 14-37 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 register (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 14-18 at the timing
of the common signals COM0 to COM3; see Figure 14-37 for the relationship between the segment signals and LCD
segments.
Table 14-18. Select and Deselect Voltages (COM0 to COM3)
Segment
Common
SEG12 SEG13
COM0 Select Select
COM1 Deselect Select
COM2 Select Select
COM3 Select Select
According to Table 14-18, it is determined that the display data register location (F040CH) that corresponds to SEG12
must contain 1101.
Figure 14-39 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, +V
LCD/−VLCD, is generated to
turn on the corresponding LCD segment.
Figure 14-37. Four-Time-Slice LCD Display Pattern and Electrode Connections
COM0
SEG
2n
COM1
SEG
2n+1
COM2
COM3
Remark 30-pin products: n = 0 to 5
44-pin products: n = 0 to 10
48-pin products: n = 0 to 12
52-pin products: n = 0 to 14
64-pin products: n = 0 to 18