UPD17073 NEC, UPD17073 Datasheet - Page 163

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

18.5 Common Signal and Segment Signal Output Waves
method) drive mode.
each having a phase difference of 1/8 from the others. In other words, voltages of 1/2V
as the reference. This display method is called the 1/2 bias drive method.
phase corresponding to each display dot. Because one segment pin can turn on or off four display dots (A, B, C, and
D) as shown in figure 18-7, sixteen phases can be output by combining lighting and extinguishing of each dot.
Cautions 1. Bit 3 of the LCD display start register is a test mode area. Therefore, do not write “1” to this
Figure 18-7 shows an example of the common signal and segment signal output waves.
The PD17073 outputs a signal with a frame frequency of 62.5 Hz using a 1/4 duty, 1/2 bias (voltage average
As the common signals, the COM0 through COM3 pins output three levels of voltages (GND, V
As the segment signals, the segment signal output pins output voltages of two levels (GND and V
Each display dot turnd on when the potential difference between a common signal and a segment signal is V
In other words, the duty factor at which each display dot turns on is 1/4.
This display method is called the 1/4 duty display method, and the frame frequency is 62.5 Hz.
Remark R: Retained
reset
LCD driver display start
register
At
Power-ON
Clock stop
CE
2. For the function of the ADCON flag, refer to 13.2 Setting of A/D Converter Power Supply.
Name
bit.
Figure 18-6. Configuration of LCD Driver Display Start Register
b
0
0
3
Flag symbol
b
0
0
2
b
O
A
D
C
N
0
0
0
1
b
C
D
E
N
R
L
0
1
0
0
0
Display OFF (all segment and common output pins output low level)
Display ON
Fixed to “0”
(BANK1)
Address
50H
Read/
Write
R/W
Sets ON/OFF of all LCD displays
DD
PD17072,17073
are output with the V
LCD0
LCD1
, and V
) having a
LCD1
LCD1
163
LCD0
)
.