King Billion Electronics Co., Ltd.

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HE89C21

HE80000 SERIES

January 20, 2003

3

V1.0E

Pin Name

Pin #

I/O

Description

LV1

45

B LCD Charge Pump Voltage V1

LV2

46

B LCD Charge Pump Voltage V2

LV3

47

B LCD Charge Pump Voltage V3

GND

48

P

Power ground Input.

RSTP_N

49

I

System Reset input pin. Level trigger, active low on this pin will put the chip in reset

state.

FXO,

FXI

50, 51

O,

B

External fast clock pin. Two types of oscillator can be selected by MO_FXTAL (‘0’

for RC type and ‘1’ for crystal type). For RC type oscillator, one resistor need to be

connected between FXI and GND. For crystal oscillator, one crystal need to be

placed between FXI and FXO. Please refer to application for details.

TSTP_P

52

I

Test input pin. Please bond this pad and reserve a test point on PCB for debugging.

But for improving ESD, please connect this point with zero Ohm resistor to GND

.

SXO,

SXI

53, 54

O,

I

External slow clock pins. Slow clock is clock source for LCD display, TIMER1,

Time-Base, DTMF generator and other internal blocks. 32768 Hz crystal or resonator

should be used for DTMF generator to function properly.

VDD

55

P

Positive power Input. 0.1 µF decoupling capacitors should be placed as close to IC

VDD and GND pads as possible for best decoupling effect.

MUTE

56

O

MUTE is open drain type output for muting microphone of telephone speech

network.

DTMFO

57

O

Dual-Tone Multiple Frequency Tone Output for dialing purpose. It can also be used

as two-channel general purpose tone generator with frequency resolution of 1 Hz.

PRTD[7..0]

58 ~ 65

B

8-bit bi-directional general purpose I/O port D. The output type of I/O pad can also

be selected by mask option MO_DPP[7..0] (‘1’ for push-pull and ‘0’ for open-drain).

As the output structure of I/O pad does not contain tri-state buffer. When using the

I/O as input, ‘1’ must be outputted before reading the pin.

The initial state of PRTD[2..0] can be determined by mask option MO_IH[2..0],

while initial state of PRTD[7..3] is always ‘1’.

PRTD[7..2] can be used as wake-up pins. PRTD[7..6] can be used as external

interrupt sources.