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DTMF App-kit, interrupt checking after dtmf-tones — Parallax Forums

DTMF App-kit, interrupt checking after dtmf-tones

ArchiverArchiver Posts: 46,084
edited 2002-12-28 19:09 in General Discussion
The DTMF App-kit works perfectly connected to my Siemens cell phone
by modifying hands free equipment.

But I intend to expand the use of the BS2 to other things as well.
That's why I have to share all the I/O pins.

The CM8880 has a CS-input.
The App-kit BS2 program (page 15) have a routine to detect the DTMF
tone on the I/O BS pin 2 (D2 from the CD8880). So the stamp activate
the CM8880 by CS, reads the status, and turn the chip off again by
CS. Thereby also activate the other pins D0-D3. That's why I need
to find another way to check for DTMF-tones, present or not, without
the use of CS.

In page 3 from DTMF App-kit, there's a list of "Functions of
Control
Register A" Bit 2 – interrupt enable, could be set to 1,
thereby let
pin 13 works as an interrupt check for DTMF-tones.

How can I active this operation mode? I tried to change some lines
in the program (e.g. OutL), but without luck so far.

Or is it another way to detect dtmf-present interrupt, without the
use of CS?
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