SH7720 Datasheet, PDF (815/1524 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 22 Analog Front End Interface (AFEIF)
Count
up
RCNTV RCNTV RCNTV
set
set
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)
Rev. 3.00 Jan. 18, 2008 Page 753 of 1458
REJ09B0033-0300