W91473 Datasheet, PDF (5/20 Pages) Winbond – 14-MEMORY TONE/PULSE SWITCHABLE DIALER WITH HANDFREE AND LOCK FUNCTION

W91473 SERIES
Pin Description, continued
SYMBOL 22-PIN
HFI, HFO
-
KT
-
DRS
-
24-PIN
12, 13
-
-
28-PIN
14, 15
9
21
I/O
FUNCTION
I, O Handfree control pins. A low pulse on the
HFI input pin toggles the handfree control
state. Status of the handfree control state
is listed in the following table:
CURRENT STATE
NEXT STATE
Hook Sw. HFO
-
Low
On Hook High
Off Hook High
On Hook -
Input
HFI ^¡õ
HFI ^¡õ
HFI ^¡õ
Off Hook
HFO
High
Low
Low
Low
Dialing
Yes
No
Yes
Yes
Off Hook Low On Hook Low No
Off Hook High On Hook High Yes
The HFI pin is pulled to VDD by an
internal resistor.
O Keytone signal output. The keytone will
be generated in all valid keys are pressed
in tone mode. Frequency is 600 Hz and
duration is 35 mS.
I Dial rate selection. This pin is pulled to
VDD by an internal resistor.
DRS
MODE
PIN
TONE/PULSE
DIAL
RATE
M/B
VDD
Pulse 10 ppS 2:3
1 Floating
Pulse 10 ppS ^1:2
VSS
Tone
-
-
VDD
Pulse 10 ppS 1:2
0 _Floating
Pulse 20 ppS 1:2
VSS
Tone
-
-
Publication Release Date: February 1995
-5-
Revision A3