CHAPTER 13 LCD CONTROLLER/DRIVER
User’s Manual
U15075EJ2V1UD
263
13.7.2 Four-time slot display example
Figure 13-12 shows how the 7-digit LCD panel having the display pattern shown in Figure 13-11 is connected to
the segment signals (S0 to S14) and the common signals (COM0 to COM3) of the
µ
PD789446 or
µ
PD789456
Subseries chip. This example displays data “123456.7” in the LCD panel. The contents of the display data memory
(addresses FA00H to FA0EH) 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 S2 and S3 pins according to Table 13-6 at the
timing of the common signals COM0 to COM3.
Table 13-6. Select and Deselect Voltages (COM0 to COM3)
Segment
Common
S2 S3
COM0 Select
Select
COM1 Deselect
Select
COM2 Select
Select
COM3 Select
Select
According to Table 13-7, it is determined that the display data memory location (FA02H) that corresponds to S2
must contain 1101.
Figure 13-13 shows examples of LCD drive waveforms between the S2 signal and the common signals. When the
select voltage is applied to S2 at the timing of COM0, an alternate rectangle waveform, +V
LCD
/–V
LCD
, is generated to
turn on the corresponding LCD segment.
Figure 13-11. Four-Time Slot LCD Display Pattern and Electrode Connections
Remark
n = 0 to 7
;;
;;
;;
;;
;
;
;;
;;
COM0
S
2n
COM1
S
2n+1
COM2
COM3
Содержание U789436 Series
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