I'm working on a remote control project, and I'd like to use DTMF so
that the controlling device can be a telephone.
I've done this sort of stuff before, but it's been a few years. When I
went to Digikey to buy a some DTMF decoders to play with, I was
confronted with the cold reality that nobody seems to make them any
more! I guess it's all done with DSPs these days.
Thing is, I'm introducing a 14-year-old to HW design and I'd like to
have as little "magic" as possible. I can explain filters in general
terms, but I'm pretty sure that trying to explain how to code FFTs will
just glaze his eyes over... (Plus we'll be working with an 8051 since
I've got a bunch and all the tools.) So I started searching junk boxes
and so on, and I have five pieces of a 28-pin DIP in a drawer labeled,
"8030 Dual Tone Decoder". The chips themselves are marked
R1
CRC8030
-3-3
8142 (Rockwell logo)
But I don't have any data on them. I'm hoping these are going to turn
out to be fairly straightforward DTMF receivers, with a 3.58MHz
oscillator, analog input, and 2-of-8 or hex output with a DV pin.
I've Googled plenty and found places that are willing to sell me some of
these parts, but I've already _got_ the parts :-) I also ran across
some references to a Mitel 8030; these could be drop-ins for the
Rockwell. But I couldn't get datasheets on the Mitel part either.
There are a few patents that use the Rockwell CRC8030 as an example of a
"typical" DTMF receiver, so that's hopeful.
Page 6 of this pdf looks tantalizing, but there's just enough info
missing so it stays just out of reach:
http://www.freepatentsonline.com/4203096.pdf
A lot of pins aren't mentioned; and what are the three that are
grounded? etc.
Any help?
--
Gordon S. Hlavenka
http://www.crashelectronics.com
Vote Ron Paul in 2008! Call 866-737-5066
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