Silan
Semiconductorsꢀ
SC9302 Series
ꢀ
(continued)
This pin is a CMOS output structure, it receives
and HFO/HDO
HKS
signals to control the dialer so as to connect or disconnect the
telephone line.
outputs low to break line when
is high (on-hook) and
PO
HKS
PO
O
CMOS OUT
HFO/HDO is low.
outputs high to make line when
is low (off-
HKS
PO
hook) or HFO is high or HDO is high.
During the off-hook state, the pin also outputs the dialing pulse train in
pulse mode dialing. While in the tone mode, this pin is always high.
This is a three-state input/output pin, provided to the user for selecting a
dialing mode among Tone/20pps/10pps.
MODE=VDD: Pulse mode, 10pps.
MODE=OPEN: Pulse mode, 20pps.
CMOS
MODE
I/O
MODE=VSS: Tone mode.
IN/OUT
During the pulse mode dialing, switching this pin to the tone mode
changes the following entrance of digits to the tone mode. When the
chips are working in the tone mode, the switching from tone to the pulse
mode will be recognized.
This pin is active only when the chip transmits tone dialing signals.
Otherwise, it always outputs low. The pin outputs tone signals to drive
the external transmitter amplifier circuit. The load resistor should not be
less than 5kΩ.
DTMF
O
CMOS OUT
This pin is a schmitt trigger input structure. Active low. Applying a
negative going pulse to this pin can toggle the HDO output once.
An external RC network is recommended to use for the input
debouncing. The pull-high resistance is 200kΩ typically.
CMOS IN
Pull-High
HDI
I
The HDO is a CMOS output structure. Its output is toggle controlled by
a negative transition on
. When HDO is toggled to high,
keeps
PO
HDI
high to hold the line. The hold function can be released by setting HFO
high or by an on-off hook operation or by another input. The HDO
HDO
O
CMOS OUT
HDI
pin can directly drive the melody generator to produce hold-line
background melody. Refer to the functional description for the hold-line
function.
Key-tone output pin. It outputs 1.2kHz tone carrier when any key is
KT
O
CMOS OUT
pressed in the pulse mode or when the function keys are pressed in the
tone mode.
(to be continued)
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.0
ꢀ
2001-11-01ꢀ
10
SILAN [ SILAN MICROELECTRONICS JOINT-STOCK ]
