Hi Kundi,

Ooops! Yes, you're right. Sorry 'bout that, it was really late when I wrote that... :o(

As I understand it, the Goertzel algorithm can be successfully implemented on an 8051 and is in facts used for DTMF decoding and such. Since we're talking about single tones here, however, this may not be the best approach.

Best regards,
Rob.