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Chapter 17
LCD Controller / Driver
User’s Manual U16504EE1V1UD00
17.8 Display Mode
17.8.1 4-time-division display example
Figure 17-10, “4-Time-Division LCD Panel Connection Example,” on page 325 shows the relationship
between a 4-time-division type 10-digit LCD panel and the display pattern shown in Figure 17-9, “4-
Time-Division LCD Display Pattern and Electrode Connections,” on page 324 and the μPD780828A
Subseries segment signals (S0 to S19) in conjunction with common signals (COM0 to COM3). The dis-
play example is “1234567890”. The display data memory contents (addresses FA7FH to FA6CH) corre-
spond to this.
An explanation is given here taking the example of the 5th digit “6” (
). In accordance with the display
pattern in Figure 17-9, “4-Time-Division LCD Display Pattern and Electrode Connections,” on page 324,
selection and non-selection voltages must be send to pins S8 and S9 as shown in Table 17-6 at the
COM0 to COM3 common signal timings.
Remark:
S: Selection, NS: Non-selection
From this, it can be seen that 0101 (COM0 is LSB) must be prepared in the display data memory
(address FA77H) corresponding to S8.
Examples of the LCD drive waveforms between S8 and the COM0 and COM1 signals are shown in Fig-
ure 17-11, “4-Time-Division LCD Drive Waveform Examples (1/3 Bias Method),” on page 326 (for the
sake of simplicity, waveforms for COM2 and COM3 have been omitted). When S8 carries 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 17-9:
4-Time-Division LCD Display Pattern and Electrode Connections
Remark:
n = 0 to 9
Table 17-6:
Selection and Non-Selection Voltages (COM0 to COM3)
Segment
S8
S9
Common
COM0
S
S
COM1
NS
S
COM2
S
S
COM3
NS
S
COM0
S
2n
COM1
S
2n + 1
COM2
COM3