CHAPTER 3 LCD CONTROLLER/DRIVER
User’s Manual U18438EJ2V0UD
39
3.8.3 Three-time-slice display example
Figure 3-19 shows how the 8-digit LCD panel having the display pattern shown in Figure 3-18 is connected to the
segment signals (S0 to S23) and the common signals (COM0 to COM2). This example displays data "123456.78" in
the LCD panel. The contents of the display data memory (addresses 00H to 17H of LCDSEG) 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 S6 to S8 pins according to Table 3-8 at the timing of the
common signals COM0 to COM2; see Figure 3-18 for the relationship between the segment signals and LCD
segments.
Table 3-8. Select and Deselect Voltages (COM0 to COM2)
Segment S6
S7
S8
Common
COM0 Deselect
Select
Select
COM1 Select
Select
Select
COM2 Select
Select
−
According to Table 3-8, it is determined that the display data memory location (06H of LCDSEG) that corresponds
to S6 must contain x110.
Figures 3-20 and 3-21 show examples of LCD drive waveforms between the S6 signal and each common signal in
the 1/2 and 1/3 bias methods, respectively. When the select voltage is applied to S6 at the timing of COM1 or COM2,
an alternate rectangle waveform, +V
LCD
/
−
V
LCD
, is generated to turn on the corresponding LCD segment.
Figure 3-18. Three-Time-Slice LCD Display Pattern and Electrode Connections
COM0
COM2
COM1
S
3n+2
S
3n
S
3n+1
Remark
n = 0 to 7