Silan
Semiconductorsꢀ
SC9302 Series
ꢀ
(continued)
This pin is a schmitt trigger input structure. Active high. Applying a
positive going pulse to HFI can toggle the HFO once and hence control
the hand-free function. The pull-low resistance of HFI is 200KΩ
typically.
CMOS IN
HFI
I
Pull-Low
An external RC network is recommended to use for the input
debouncing.
The HFO is a CMOS output structure. Its output is toggle controlled by
a positive transition on HFI pin. When HFO is high, the hand-free
function is enabled and
outputs high to connect the line.
PO
HFO
O
CMOS OUT
The hand-free function can be released by setting HDO high or by an
on-off-hook operation or by another HFI input. Refer to the functional
description for the hand-free functional operation.
This is a three-state input/output pin, provided to the user for controlling
the long distance call function with a lock-switch.
LOCK
I/O
CMOS IN/OUT LOCK=OPEN: Normal dialing (no lock).
LOCK=VDD: “0,9” is inhibited for use as the first key input.
LOCK=VSS: “0” is inhibited for use as the first key input.
This is an NMOS open drain output pin. It outputs the BCD code of the
dialing digits to the LCD driver chip (SC16XX series) or µC for dialing
number display. Refer to the functional description for the detailed
timing.
DOUT
O
O
NMOS OUT
NMOS OUT
NMOS open drain output. When dialing, it outputs a series of pulse train
for the DOUT data synchronization. The DOUT data is valid at the falling
edge of clock.
CLOCK
VDD
VSS
I
I
--
--
Positive power supply, 2.0V~5.5V for normal operation.
Negative power supply.
FUNCTION DESCRIPTIONS
1. KEYBOARD MATRIX
The
~
C1 C4
and
~
R1 R4
make up of a keyboard matrix. Together with a standard 4x4 keyboard, the
keyboard matrix is used for dialing entrance. In addition, the keyboard matrix provides resistor option for different
dialing specification selections. The keyboard arrangement for each of the SC9302 series are listed in KEYBOARD
INFORMATION.
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.0
ꢀ
2001-11-01ꢀ
11
SILAN [ SILAN MICROELECTRONICS JOINT-STOCK ]
