SH7721 datasheet(815/1524 Pages) RENESAS

815 / 1524 page

Section 22

Analog Front End Interface (AFEIF)

Rev. 3.00 Jan. 18, 2008 Page 753 of 1458

REJ09B0033-0300

Count

RCNTV

set

RCNTV

set

RCNTV

set

RCNTV

set

1. First INT occur. RCEN (ACTR2) turns on.

2. From 2nd INT, read the RCNTV.

3. After acknowledge the ringing, RCEN (ACTR) turns off and goes

to off hook operation.

Figure 22.8

Ringing Detect Sequence

(2)

Dial Pulse Sending Sequence

A dial pulse is generated according to the conditions that are specified in ACTR2, and is sent out

to AFE_RLYCNT.

As the basic clock for generating the dial pulse is AFE_FS that is input from AFE, it is necessary

to make AFE in operating state. An example of control sequence for dial pulse sending is shown

below.

Note that this sequence cannot be operated when RLYC bit (ACTR2) is low.

[Conditions]

Make ratio:

33%

Pulse interval:

20 PPS

Minimum pause: 600 ms

Dial number:

0,1234567 ("," means pause)

[Control sequence]

1. Set PPS (ACTR2)

→ "1", MKR → "9EH1", MNRPCNT → "1680H"

2. Set DPNQ

→ "AF12H".

3. Set RLYC

→ "H". (Off Hook)

4. Detect dial tone or wait specific period. (Controlled by software)

5. Write "1" to DPST (ACTR2). (Start sending dial pulse)

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