W91590 SERIES
Publication Release Date: July 1995
- 3 - Revision A3
PIN DESCRIPTION
SYMBOL 22-PIN 24-PIN 28-PIN I/O FUNCTION
Column-
Row
Inputs
1−7
&
18−22
1−7
&
20−24
1−8
&
24−28
I The keyboard input may be from either the
standard 9 × 5 keyboard or an inexpensive
single contact (form A) keyboard. Electronic
input from a µC can also be used.
A valid key entry is defined by a single row
being connected to a single column.
XT,
9, 10 9, 10 11, 12 I, O A built-in inverter provides oscillation with an
inexpensive 3.579545 MHz crystal or
ceramic resonator.
T/P
11 11 13 O
The T/P
is a conventional CMOS
N-channel open drain output.
The output transistor is switched on during
pulse and tone mode dialing sequence and
flash break. Otherwise, it is switched off.
HPM
MUTE
- - 23 O The HPM MUTE is a conventional inverter
output. During pulse dialing, flash, hold, and
mercury mute functions, this pin will output
an active high. It remains in a low state at all
other times.
MODE 15 17 19 I Pulling mode pin to VSS places the dialer in
tone mode.
Pulling mode pin to VDD places the dialer in
pulse mode (M/B = 2:3).
Leaving mode pin floating places the dialer
in pulse mode (M/B = 1:2).
12 14 16 I Hook switch input.
= 1: On-hook state. Chip in sleeping
mode, no operation.
= 0: Off-hook state. Chip enabled for
normal operation.
pin is pulled to VDD by internal resistor.
/
13 15 17 O N-channel open drain dialing pulse output
(Figure 1).
Flash key causes
to go active when in
pulse mode and tone mode.
NC 17
(W91590)
19
(W91590A)
22
(W91590B/C)
- No connection.
