HT9245-1AL/BL/CL/DL
15-Memory Tone/Pulse Dialer
Features
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Universal specification
Operating voltage: 2.0V~5.5V
Low stand-by current
Low memory retention current: 0.1
µ
A (Typ.)
Tone/pulse switchable
Interface with LCD driver
32 digits for redialing
32 digits for the SA memory dialing
One-key redialing
Pause and P
→
T key for PBX
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5
×
5 keyboard matrix
Make/Break ratio control
3.58MHz crystal or ceramic resonator
Hand-free control
Hold-line control
Pause, P
→
T can be saved for redialing
Memory number: 15 memories
Keytone function
Lock function
CD key
General Description
The HT9245-1 series tone/pulse dialers are
CMOS LSIs for the telecommunication system.
The HT9245-1 series tone/pulse dialers are of-
fered in various packages from 22 DIP to 28
DIP. The 22 DIP version is suitable for low cost
applications, while the 28 DIP version supplies
versatile functions such as: Hold-line, Hand-
free, IDD lock and LCD dialing number display
interface, all of which are suitable for feature
phone applications.
The HT9245-1 provides SA, Redial, 3 one-touch
(EM1~ EM3) and 10 two-touch (M0~M9) mem-
ory dials for speed dialing in either pulse or tone
mode.
Selection Table
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21st Sep ’95
HT9245-1AL/BL/CL/DL
Package Information
Keyboard Information
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21st Sep ’95
HT9245-1AL/BL/CL/DL
Block Diagram
Pin Description
Pin Name
I/O
Internal
Connection
Description
These pins construct a 5
×
5 keyboard matrix to perform the
keyboard input detecting functions. When on-hook (HKS=
high) all the pins are set to high. While off-hook the column
group (C1~C4) stays low and the row group (R1~R5) is set to
high for key input detecting.
An inexpensive single contact 5
×
5 keyboard can be used as an
input device. Pressing a key connects a single column to a
single row, and actuates the system oscillator to result in a
dialing signal output. If more than two keys are pressed at the
same time, no response can be brought about. The key-in
debounce time is 20ms. Refer to the keyboard table for keyboard
arrangement and to the functional description for dialing
specification selection.
C1~C4
R1~R5
I/O
CMOS
IN/OUT
X1
I
X2
O
The system oscillator consists of an inverter, a bias resistor
and the necessary load capacitor on chip. Connecting a
standard 3.579545MHz crystal or ceramic resonator to X1 and
OSCILLATOR
X2 terminals can implement the oscillator function. The
oscillator is turned off in the stand-by mode, and is actuated
whenever a keyboard entry is detected.
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21st Sep ’95
HT9245-1AL/BL/CL/DL
Internal
Connection
Pin Name
I/O
Description
The XMUTE is an CMOS structure pulled to VSS during
dialing signal transmitting. Otherwise, it stays at "high". The
XMUTE is used to mute the speech circuit when transmitting
the dial signal.
This pin is used to monitor the status of the hook-switch and
its combination with HFI can control the PO pin output to
make or break the line.
HKS=VDD: On-hook state (PO=low). Except HFI/HDI (hand-
free/hold-line control input), other functions are
all disabled.
HKS=VSS: Off-hook state (PO=high). The chip is in the stand-by
mode and ready to receive the key input.
This pin is a CMOS output structure which receives the HKS
and HFO signals to control the dialer so as to connect or
disconnect the telephone line.
PO outputs low to break line when HKS is high (on-hook) and
HFO is low (hand-free inactive). PO outputs high to make line
when HKS is low (off-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 input pin, provided to the user for selecting a dialing
mode among Tone/10pps.
MODE=VDD: Pulse mode, 10pps.
MODE=VSS: Tone mode.
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 the tone to the pulse mode will be recognized.
The MUTE is an CMOS structure that is pulled to VDD during
Tone (DTMF) output transmitting. Otherwise, it remains "low"
at all time.
This is a Make/Break ratio select pin in the pulse mode.
Otherwise, it has no functions.
M/B=VDD: Make/Break ratio is 40/60.
M/B=VSS: Make/Break ratio is 33/66.
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 5K
Ω
.
XMUTE
O
CMOS OUT
HKS
I
CMOS IN
Pull-High
PO
O
CMOS OUT
MODE
I
CMOS IN
MUTE
O
CMOS OUT
M/B
I
CMOS IN
DTMF
O
CMOS OUT
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21st Sep ’95
HT9245-1AL/BL/CL/DL
Internal
Connection
Pin Name
I/O
Description
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 recommanded to use for the input
debouncing. The pull-high resistance is 200K
Ω
typically.
The HDO is a CMOS output structure. Its output is toggle-
controlled by a negative transition on HDI. When HDO is
toggled to high, PO keeps 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 HDI input. The HDO pin can
directly drive the HT3810 series melody generators to produce
hold-line back ground melody. Refer to the functional
description for the hold-line function.
This pin is a schmitt trigger input structure. Active low.
Applying a negative going pulse to HFI can toggle HFO once
and hence control the hand-free function. The pull-high
resistance of HFI is 200K
Ω
typically.
An external RC network is recommanded to use for the input
debouncing.
The HFO is a CMOS output structure. Its output is toggle-
controlled by a negative transition on the HFI pin. When HFO
is high, the hand-free function is enabled and PO outputs high
to connect the line.
The hand-free function can be released by an on-off-hook
operation or by another HFI input or by setting HDO high.
Refer to the functional description for the hand-free functional
operation.
This is an NMOS open drain output pin. It outputs the BCD
code of the dialing digits to the LCD driver chip (HT16XX
series) or
µ
C for dialing number display. Refer to the
functional description for the detailed timing.
NMOS open drain output. When dialing, it outputs a series of
pulse trains for the DOUT data synchronization. The DOUT
data is valid at the falling edge of the clock.
Key-tone output pin. It outputs 1.2KHz tone carrier when any
key is pressed in the pulse mode or when the function keys are
pressed in the Tone (DTMF) mode.
For IC test only. TEST=VDD for normal operation.
HDI
I
CMOS IN
Pull-High
HDO
O
CMOS OUT
HFI
I
CMOS IN
Pull-High
HFO
O
CMOS OUT
DOUT
O
NMOS OUT
CLOCK
O
NMOS OUT
KT
TEST
O
I
CMOS OUT
CMOS IN
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21st Sep ’95
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