W91580 Datasheet, PDF (4/19 Pages) Winbond – 24-MEMORY TONE/PULSE SWITCHABLE DIALER WITH HANDFREE AND HOLD FUNCTIONS

W91580 SERIES
Pin Description, continued
SYMBOL 22-PIN 24-PIN 28-PIN I/O
FUNCTION
HFI, HFO
-
12, 13 14, 15 I, O _{Handfree control pins. A low pulse on the HFI}
input pin toggles the handfree control state. The
status of the handfree control state is described by
the following table:
CURRENT STATE
Hook SW.
-
HFO
Low
On Hook High
Off Hook
On Hook
High
-
Off Hook Low
Off Hook High
NEXT STATE
Input
HFI
HFO
High
Dialing
Yes
HFI
Low
No
HFI
Low
Yes
Off Hook Low
Yes
On Hook Low
No
On Hook High
Yes
HFI pin is pulled to VDD by internal resistor.
KT
-
-
9
O Keytone signal output. A keytone will be generated
whenever a valid key is pressed. Frequency is 600
Hz and duration is 35 mS.
DRS
-
-
21
I Dial rate selection.
This pin is pulled to VDD by an internal resistor.
DRS
1
0
MODE
PIN
VDD
Floating
VSS
VDD
Floating
VSS
TONE/PULSE
Pulse
Pulse
Tone
Pulse
Pulse
Tone
DIAL
RATE
M/B
10 ppS 2:3
10 ppS 1:2
10 ppS 1:2
20 ppS 1:2
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