Silan

Semiconductors

SC84520

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

5

PIN DESCRIPTION

Pin Name

I/O

Description

OPT

I/O

INPUT: 200k

Ω pull low to VSS.

When OPT is connected to VDD, SC84520 will enter test mode. In test mode, L will

be the output of X1, while M will be the output of X2. Toggling R key can change

these output to be Y1, Y2 or Z1, Z2 respectively.

OUTPUT: 2kHz Z-axis LED-driving source with A/D/E/F version.

“1” = VDD, “0” = floating

High duty is about 60

µs.

OSC OUT

O

The RC oscillation clock output. Or 3mA sink current output for X, Y photo emitters.

OSCR

I

Connect 50k

Ω± 1% precise resistor for oscillation.

CLK/RTS

I/O

Connect to 8024 auxiliary port CLK line in PS/2 mode or connect directly to RS232C

RTS pin in serial mode. Auto-detect the operating port by this pin.

DATA/RXD

I/O

Connect to 8024 auxiliary port DATA line in PS/2 mode or connect directly to

RS232C RXD pin in serial mode.

--

Negative power input.

RI

M

I/O

L

I/O

Three key-switches inputs. 200k

Ω resistor pull low.

In Z-axis key mode, M key toggling can change the scrolling speed from low to high.

X1

X2

Y1

Y2

I

Three step dynamic input impedance. If OSC OUT is not connected to LEDs, the

dynamic input impedance will be off.

Use current comparator to measure photo-couples “ON”, or “OFF”.

Z1

Z2

I

Z-axis input.

Photo mode: Three steps dynamic input impedance. Current comparator input.

Key mode: 200k

Ω resistor pull low. 7 levels increased by “M” key.

Voltage mode: 200k

Ω resistor pull low. 7 level voltage comparator.

Mechanical mode: 13.2 k

Ω resistor pull low, Current comparator input.

VSS

Negative power.

Power line.