SA589 FAMILY

sames

2/14

Pin

Pin

number

name

1

NC

Not connected

3

IMP

'Loop disconnect' dialling output

4

SELECT

LD/DTMF selection, IDP and B/M ratio programming

5

MASK

Output to disable speech circuit during pulse dialling and recall

(see note 1)

6

OSC OUT

Connections for 560kHz ceramic resonator

7

OSC IN

8

FILT IN

Unity gain amplifier input and output for DTMF tone filtering

9

FILT OUT

10

HSW

Hookswitch input - a logic 1 at this pin is used to indicate 'Off-

Hook'

11

V

SS

Negative supply

12

V

DD

Positive supply

13

PAUSE OUT Active high indicating a pause when dialling from memory

17

MF OUT

Unfiltered DTMF output

18

MUTE

Output active during keying and tone transmission (see note 2)

19

COL1

20

COL2

21

COL3

26

COL4

27

COL5

2

COL6

16

COL7

22

ROW1

Connections for 38 key single contact keypad

23

ROW2

24

ROW3

25

ROW4

14

ROW 5

15

ROW 6

28

ROW 7

1.

MASK may be used to disconnect the whole speech circuit in order to maintain the break

condition whilst on-hook and during a TBR (Timed Flash) operation.

2.

MUTE is provided to disable the microphone while maintaining the loop during DTMF

transmission.

OPERATION

Power-on

When power is applied to the chip, a power-on reset circuit operates and ensures that the

Memories are cleared and all logic is reset. The power-on reset circuit is designed such that

if the chip supply voltage drops to a level at which the memories may be corrupted, it will

always, under all conditions, clear the memory, so that corrupt data is not retained.

Function

TABLE 1:

PIN FUNCTIONS