W91F820N Datasheet, PDF (4/20 Pages) Winbond – 13-FLASH MEMORY TONE/PULSE DIALER WITH HANDFREE, LOCK AND HOLD FUNCTIONS

Preliminary W91F820N SERIES
Pin Description, continued
SYM. 20-PIN 22-PIN I/O
FUNCTION
H/P MUTE 6
6
I The H/P MUTE is a conventional inverter output. During pulse
dialing, flash break or hold period, this output is active high;
otherwise, it remains in low state.
DP
12 14 O N-channel open drain dialing pulse output.
Flash key will cause DP to be active in either tone mode or pulse
mode.
The timing diagram for pulse mode is shown in Figure 1(a, b).
DTMF
14
15 O During pulse dialing, this pin remains in a low state regardless of
the keypad input. In tone mode, it will output a dual or single
tone.
A detailed timing diagram for tone mode is shown in Figure 2(a,
b).
OUTPUT FREQUENCY
Specified Actual Error %
R1
697
699 +0.28
R2
770
766
-0.52
R3
852
848
-0.47
R4
941
948
+0.74
C1
1209
1216
+0.57
C2
1336
1332
-0.30
C3
1477
1472
-0.34
VDD, VSS
HFI, HFO
15, 7 17, 7 I Power input pins for the dialer chip. VDD is the power and VSS is
the ground.
- 11, 12 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 listed in the
following table:
CURRENT STATE
NEXT STATE
HOOK SW. HFO INPUT
HFO DIALING
-
Low _HFI
High Yes
On Hook High _HFI
Low
No
Off Hook High _HFI
Low Yes
On Hook
- Off Hook Low 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.
A detailed timing diagram is shown in Figure 3.
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