UPD17073 NEC, UPD17073 Datasheet - Page 159

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

18.2 LCD Drive Voltage Generation Block
connect a capacitor to the REG
as shown in Figure 18-2.
flag is set to “1”, the LCD drive voltage generation block does not operate. For the LCDEN flag, refer to 18.4 Common
Signal Output and Segment Signal Output Timing Control Blocks.
differ if the values of C1, C2, and C3 are changed.
Remark ( ): pin number
The LCD drive voltage generation block generates a voltage to drive the LCD.
The PD17073 supplies the LCD drive voltage from an external doubler circuit. To configure a doubler circuit,
Figure 18-2 shows an example of configuration of the doubler circuit. To use a voltage of 3.1 V (TYP.), connect
To operate the doubler circuit, the LCDEN flag of the LCD display start register must be set to “1”. Unless this
Note that, because of the configuration of the doubler circuit, the values of the LCD drive voltages (V
LCD
Figure 18-2. Configuration of Doubler Circuit
0, CAP
REG
REG
CAP
CAP
LCD
LCD
LCD
LCD
LCD
0, CAP
1
1
0
0
LCD
1, and REG
C1
C2
C3
LCD
1 pins.
C1 = C2 = 0.1 F
C3 = 0.01 F
PD17072,17073
LCD1
and V
LCD0
159
)