NEC mPD780852 Series, Preliminary User'S Manual

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CHAPTER 16 LCD CONTROLLER/DRIVER
Preliminary User’s Manual U14581EJ3V0UM00
16.8 Display Mode
16.8.1 4-time-division display example
Figure 16-10 shows the connection of a 4-time-division type 10-digit LCD panel with the display pattern shown
in Figure 16-9 with the
µ
PD780852 Subseries segment signals (S0 to S19) and common signals (COM0 to COM3).
The display example is “1234567890,” and the display data memory contents (addresses FA59H to FA6CH)
correspond to this.
An explanation is given here taking the example of the 5th digit “6” ( ). In accordance with the display pattern
in Figure 16-9, selection and non-selection voltages must be output to pins S8 and S9 as shown in Table 16-6 at
the COM0 to COM3 common signal timings.
Table 16-6. Selection and Non-Selection Voltages (COM0 to COM3)
Segment S8 S9
Common
COM0 S S
COM1 NS S
COM2 S S
COM3 NS S
S: Selection, NS: Non-selection
From this, it can be seen that 0101 must be prepared in the display data memory (address FA64H) corresponding
to S8.
Examples of the LCD drive waveforms between S8 and the COM0 and COM1 signals are shown in Figure 16-
11 (for the sake of simplicity, waveforms for COM2 and COM3 have been omitted). When S8 is at the selection voltage
at the COM0 selection timing, it can be seen that the +V
LCD
/–V
LCD
AC square wave, which is the LCD illumination
(ON) level, is generated.
Figure 16-9. 4-Time-Division LCD Display Pattern and Electrode Connections
,,
,,
,,
,,
,,
,,
,
,
,
,
,
,
COM0
S
2n
COM1
S
2n + 1
COM2
COM3
n = 0 to 9