W91550 WINBOND [Winbond], W91550 Datasheet - Page 5

• Manufacturer Part Number: W91550
• Description: 13-MEMORY TONE/PULSE DIALER WITH LCD AND LOCK FUNCTION
• Manufacturer: WINBOND [Winbond]

Pin Description, continued
HFI , HFO
SYMBOL
CP, CN
LOCK
TEST
V
LCD
57, 58
60, 61
PIN
64
37
59
I, O Handfree control pins. A low pulse on the HFI input pin toggles the
I/O
I
I
I
I
handfree control state.
Status of the handfree control is listed in the following table:
Detailed timing diagram is shown in Figure 4.
The LOCK pin is used to prevent "0" or "9" dialing under PABX
system long distance call control. When the first key input after reset
is "0" or "9", all the key inputs, including "0" or "9" key, become
invalid, and the chip generates no output.
The telephone is reinitialized by a reset.
The following table describes the functions of the LOCK pin:
In normal operation, pulling the TEST pin to V
tone. In testing operation, pulling the TEST pin to V
single tone to be created by pressing two keys simultaneously, and all
of the timing parameters for pulse dialing are faster than in normal
operation.
Power supply pin for LCD driver.
A 1 F capacitor is connected between V
CP is the voltage control capacitor positive pin.
CN is the voltage control capacitor negative pin.
A 1 F capacitor is connected between these two pins.
HFI pin is pulled to V
Hook SW.
CURRENT STATE
On Hook
Off Hook
On Hook
Off Hook
Off Hook
V
LOCK PIN
Floating
V
SS
DD
HFO
Low
High
High
Low
High
- 5 -
"0", "9" dialing inhibited
"0" dialing inhibited
Normal dialing
DD
FUNCTION
by internal resistor.
HFI
Off Hook
HFI
HFI
On Hook
On Hook
Input
FUNCTION
Publication Release Date: November 1997
NEXT STATE
W91550DN SERIES
HFO
High
Low
Low
Low
High
Low
LCD
and V
DD
Dialing
Yes
Yes
Yes
Yes
No
No
inhibits the single
SS
SS
.
enables a
Revision A3