sames

SA2532

7/22

Microcontroller Interface

The keypad Row and Column Pins can readily be driven by a Microcontroller Interface. When

configured in this way the SA2532 inputs and dials the corresponding digits in either LD or

DTMF.

The LNR store can be used to buffer digits to allow high speed data entry. See

Application Note AN3002A for details.

Tone Ringer

The Tone Ringer of the SA2532 incorporates a Discriminator Circuit and adjustable Melody

Generator

Ring Frequency Discrimination

The Ring Frequency Discriminator assures that only signals with a frequency between

20Hz and 60Hz (option 13 Hz to 60 Hz) are regarded as valid ring signals.

When a valid ring signal is present for 73ms continuously, the melody generator is

activated and remains active as long as the ring signal is present.

Once the melody generator has been started, the ring signal is continuously monitored

and the melody generator is instantly turned on or off according to the momentary

presence of a valid or unvalid ring signal respectively (until next POR or off-hook).

Melody Generator

When a Valid Ring Signal is detected the Melody generator is activated and creates a

ringing Signal comprising 3 frequencies F1 (1065Hz), F2 (1420Hz) and F3 (1734Hz).

These frequencies are repeated in a sequence of 6 time slots constructed by the

frequencies

F1

F2

F3

F1

F2

F3

This sequence is repeated 1, 4, 7 or 10 times per second as indicated by the connection

of the RR Pin to one of the four rows of the keyboard.