Problems with DTMF Generatiom

[b1arrk5]

I got a 16F877 to generate dtmf ok, using the filter shown in the manual, however I had to amplify it to get a decoder to accept tones. I used a 358 op amp set up, non inverting, with a gain of around three, and it worked great. I used the Teridian 75T204 decoder. I can probably dig up the schematic if you need. Hope this helps!

Jerry.

[mister_e]

DTMFOUT work fine with a 20MHZ crystal.

If you already use a 20MHZ crystal, you may need to redesign or improve the low-Pass filter and, probably, increase the amplitude of the signal.