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| LICENSE | ||
| MT8870.cpp | ||
| MT8870.h | ||
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MT8870
Arduino library for MT8870 DTMF decoder (breakout)
Description
This library reads the signals of the MT8870 chip. If data is available one can read it raw or as text.
DTMF = Dual Tones Multiple Frequency, it are the tones you hear when you press buttons on your phone.
A=697 Hz B=770 Hz C=852 Hz D=941 Hz E=1209 Hz F=1336 Hz G=1477 Hz H=1633 Hz
Interface
- MT8870() constructor
- void begin(STQ, Q1, Q2, Q3, Q4) defines which pins to use.
Technically it is possible to have readout multiple decoders
with one MT8870 object by calling begin() with other pins.
- STQ = data available signal
- Q1..Q4 = datapins
- Calling begin resets the lastRead char
- bool available() returns true if there is a DMTF signal
- char read() reads the character available. returns 255 if no signal available.
- uint8_t readRaw() returns 0 .. 15 or 255 if no signal is available.
- uint8_t lastRaw() returns the last code read 0 .. 15 or 255.
Note this is a cached value from a readRaw / read call.
Future / ideas / improvements
- buffer like Serial? (how to fill? interrupt? example sketch?)
- DMTF tone generation?
- more examples!
DTMF tones, uses one from A..D one from E..H.
| Name | Frequency |
|---|---|
| A | 697 Hz |
| B | 770 Hz |
| C | 852 Hz |
| D | 941 Hz |
| E | 1209 Hz |
| F | 1336 Hz |
| G | 1477 Hz |
| H | 1633 Hz |
Operations
See examples.