AS2574BN austriamicrosystems AG, AS2574BN Datasheet - Page 2

• Manufacturer Part Number: AS2574BN
• Description: 20 NUMBER ONE TOUCH DIALLER WITH SERIAL BUS FOR DISPLAY DRIVER
• Manufacturer: austriamicrosystems AG

Data Sheet
Pin Description
Continues…
Rev. 1
Pin #
11 - 15
5 - 10
23
16
17
18
19
20
21
22
1
2
3
4
Pin Node
MASK
OSC2
OSC1
C1 - 6
R1 - 5
SDA
SCL
MR
CD
MT
ER
DP
DT
LS
Description
Oscillator pins for ceramic resonator (681 kHz)
The SCL output is used to clock all data into the display driver
The SDA output is used to transfer data into the display driver
Output for controlling loudhearing and handsfree facilities, active high
(see hook state diagramme)
Mask output, active high during pulsing (make and break period, see timing
diagrammes).
Chip disable input, active low.
When CD is low, the circiut is disabled.
If this pin is pulled to V
2 sec., the circuit is reset*. If the pin is pulled to V
line break is ignored.
* If in ACP or monitor state, reset also means return to idle state.
Transmit mute output, active high when MR is high and when
the Mute key has been activated (see timing diagrammes).
Earth recall input/output, active high during ER but when forced to V
the flash is enabled.
Dial tone input.
This input is scanned when invoking ACP or a pause is read in a digit string:
* Reset means that dialling is stopped and the circuit returns to standby.
Hook switch control, dial pulse and flash output; low during Idle and break
periods and high during off-hook (see timing diagrammes).
Keyboard columns
Keyboard rows
Mute output, active high during signalling (see timing diagrammes).
If the circuit was in ACP state, the reset will also return the circuit to idle state.
DT pin
Open
Low
High
Function
Pause duration 4.1 sec
If a high is not detected within 8 sec., the circuit is
reset *
If the pin is high for > 1.15 sec., the pause is termi-
nated and the dialling continued. Noise immunity > 8 ms
SS
2
during Off-hook (indicating a disconnect) for more than
SS
for less than 2 sec., the
DD
AS2574B
,
Jan. 1995