Four-Time Slot Display Example - NEC UPD789426 Series User Manual

8-bit single-chip microcontrollers
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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
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." (
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.
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
turn on the corresponding LCD segment.
Figure 13-11. Four-Time Slot LCD Display Pattern and Electrode Connections
S
2n+1
Remark
n = 0 to 7
CHAPTER 13 LCD CONTROLLER/DRIVER
Table 13-6. Select and Deselect Voltages (COM0 to COM3)
Segment
Common
COM0
COM1
COM2
COM3
S
2n
User's Manual U15075EJ2V1UD
) displayed in the seventh digit. To display "6." in the LCD
S2
S3
Select
Select
Deselect
Select
Select
Select
Select
Select
COM0
COM2
µ
µ
PD789446 or
PD789456
/–V
, is generated to
LCD
LCD
COM1
COM3
263

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