SC9318-033

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.2

2003.05.20

Http: www.silan.com.cn

Page 9 of 29

(Continued)

Pin No.

Symbol

Description

60

61

62

C1

63

C2

Voltage double boosting pin;

Voltage doubler boosting pin for driving the LCD.

A capacitor (0.1

µF Typ.) is connected to boost the voltage.

The VLCD pin outputs voltage (3.0V), which has been doubled from the constant

voltage (VEE: 1.5V) using the capacitors connected between C1 and C2. That

potential is supplied to the LCD drivers. If the internal VLCD OFF bit is set to “1”by

program, an external power supply can be input through the VLCD pin to drive the

LCD.

At this time, the VLCD/2 potential, whose VLCD voltage is divided using registers, is

output from the C2 pin.

64

Constant voltage supply pin;

1.5V constant voltage supply pin for driving the LCD.

A stabilizing capacitor (0.1

µF Typ.) is connected. This is a reference voltage for the

A/D converter, key input, and the LCD common output’

s bias potential.

the pins for I/O ports and additional functions (e.g., A/D converter) are set to I/O port input pins, while

the IFIN/IN pins become IF input pins.

2. When in PLL OFF mode (when the three bits in the internal reference ports all show “1”), the IFIN and

FMIN, AMIN pins are pulled down, and DO1 And DO2 are at high impedance.

3. When in CLOCK STOP mode (during execution of CKSTP instruction), the output port and the LCD

output pins are all at low level, while the constant voltage circuit (VEE), the voltage doubler circuit (VLCD),

and the power supply for the crystal oscillator (VXT) are all off.

4. When the device is being reset, the contents of the output ports and internal ports are undefined and

initialization by program is necessary.