Datasheet

RL78/L12 CHAPTER 14 LCD CONTROLLER/DRIVER
R01UH0330EJ0200 Rev.2.00 644
Dec 13, 2013
14.10 Display Modes
14.10.1 Static display example
Figure 14-28 shows how the three-digit LCD panel having the display pattern shown in Figure 14-27 is connected to the
segment signals (SEG0 to SEG23) and the common signal (COM0). This example displays data “12.3” in the LCD panel.
The contents of the display data register (F0400H to F0417H) correspond to this display.
The following description focuses on numeral “2.” ( ) displayed in the second digit. To display “2.” in the LCD panel, it
is necessary to apply the select or deselect voltage to the SEG8 to SEG15 pins according to Table 14-15 at the timing of
the common signal COM0; see Figure 14-27 for the relationship between the segment signals and LCD segments.
Table 14-15. Select and Deselect Voltages (COM0)
Segment
Common
SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15
COM0 Select Deselect Select Select Deselect Select Select Select
According to Table 14-15, it is determined that the bit-0 pattern of the display data register locations (F0408H to
F040FH) must be 10110111.
Figure 14-29 shows the LCD drive waveforms of SEG11 and SEG12, and COM0. When the select voltage is applied to
SEG11 at the timing of COM0, an alternate rectangle waveform, +V
LCD/−VLCD, is generated to turn on the corresponding
LCD segment.
COM1 to COM3 are supplied with the same waveform as for COM0. So, COM0 to COM3 may be connected together
to increase the driving capacity.
Figure 14-27. Static LCD Display Pattern and Electrode Connections
SEG 8n+3
SEG 8n+2
SEG 8n+5
SEG 8n+1
SEG 8n
SEG 8n+4
SEG 8n+6
SEG 8n+7
COM0
Remark 30-pin products: n = 0
44-pin products: n = 0, 1
48-, 52-pin products: n = 0 to 2
64-pin products: n = 0 to 3