AS2578B austriamicrosystems AG, AS2578B Datasheet - Page 3

• Manufacturer Part Number: AS2578B
• Description: TELEPHONE CONTROLLER WITH 13 MEMORIES AND 2-WIRE BUS
• Manufacturer: austriamicrosystems AG

Data Sheet
Power On Reset
The on chip power on reset circuit monitors the supply
voltage (V
reference voltage, Vref (typically 1.1V), the oscillator is
inhibited. When V
ms/V), a reset signal is generated to assure correct start-
up.
Rev. 3
Pin Description cont´d
Note: "Open" means
Pin #
18
19
20
21
22
23
24
25
26
27
28
DD
). As long as V
Symbol
DPN
V
DD
MV
RR
GL
R4
R3
R2
R1
C5
C6
AP
C5
DD
rises above Vref (t
100 k .
DD
remains below the internal
Function
Dial Pulse Output
This is the push-pull output for controlling the hook-switch transistor. It is low during on-
hook and break periods and high during off-hook (see timing diagrammes).
Ground Loop Output
This push-pull output is high during ground loop
Positive Power Supply
Keyboard Rows
Keyboard Column (AS2578)
This column is for the memory keys
Keyboard Column (AS2578B)
This column is for centrex keys (A - D keys). Automatic pause insertion and Temporary
MF select 1 are fixed enabled (AP open)
Access Pause Select Input (AS2578)
This input is used to select the automatic access pause insertion or sliding cursor (no
centrex keys):
Keyboard Column (AS2578B)
This column is for the memory keys
Melody Volume Select Input
This input is used to select the volume of the melodies in 4 steps by connecting the MV
pin to row 1, 2, or 3. Leaving the pin open is the default setting (max. volume).
Repetition Rate Select Input
This input is used to select the repetition rate of the melodies. 4 different rates can be
selected by either leaving the pin open (default) or connecting it to column 1, 2, or 3.
AP pin
High
Open
Low
RISE
= 1 s/V to 50
Sliding cursor enabled
Automatic pause insertion enabled
Sliding cursor and pause disabled
3
Initial Setup
A low to high transition on the CE input will initiate an
automatic setup, i.e. the pin options are scanned and
(when an EEPROM is connected) the stored LM codes
and melody settings are read from the EEPROM. This is
done independently of the hook state (see timing
diagrammes).
Function
Temporary MF select 2
Temporary MF select 1
Temporary MF select 1
AS2578 /B
March 1997