Datasheet

CHAPTER 15 LCD CONTROLLER/DRIVER
User’s Manual U18698EJ1V0UD 393
15.7 Display Modes
15.7.1 Static display example
Figure 15-11 shows how the three-digit LCD panel having the display pattern shown in Figure 15-10 is connected
to the segment signals (SEG0 to SEG21) and the common signal (COM0) of the 78K0/LC3 chip. This example
displays data "2.3" in the LCD panel. The contents of the display data memory (FA40H to FA55H) 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 15-5 at
the timing of the common signal COM0; see Figure 15-10 for the relationship between the segment signals and LCD
segments.
Table 15-5. Select and Deselect Voltages (COM0)
Segment SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15
Common
COM0 Select Deselect Select Select Deselect Select Select Select
According to Table 15-5, it is determined that the bit-0 pattern of the display data memory locations (FA48H to
FA4FH) must be 10110111.
Figure 15-12 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 15-10. 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 n = 0, 2