Tiny Arduino library for decoding DTMF tones on an ATtiny.
by Bruce Ratoff, KO4XL@yahoo.com, https://github.com/bratoff
This library uses Goertzel's algorithm to detect and decode DTMF characters.
Supported processors:
ATtiny85
ATtiny84*
ATtiny84A*
ATtiny841*
Note: At present, only A0 thru A7 are supported on the 84, 84A and 841 processors
Constructors:
tinyDTMF(byte analogPin) - analogPin is optional. Default pin is A2 if not specified.
tinyDTMF(byte analogPin, byte threshold) - specify magnitude threshold to recognize tones
Member Functions:
void begin(void) - Initialize the decoder.
long getSample(void) - Fill sample buffer. Returns calculated sample rate in Hz.
byte procSample(void) - Decode sample buffer, return ASCII key or 0
byte getKey(void) - return last decoded key or 0
byte getAin(void) - return analog pin number
long getSampleFreq(void) - return last calculated sample frequency
byte getThreshold(void) - return magnitude threshold for recognition
IMPORTANT: getSample() relies on an Arduino core with an accurate implementation of micros() with good resolution. I use this one: https://github.com/SpenceKonde/ATTinyCore
Version 1.0.0 - 14 Aug 2021 - Initial release