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# AnalogKeypad

Library for (Robotdyn) 4x4 and 4x3 analog keypad.


## Description

AnalogKeypad is a simple library to read the keys from a (Robotdyn) 4x4 or 4x3 keypad.
No other keypads are tested, but they should work with this library after adjusting
the **MAGIC NUMBERS** in the function **rawRead()**.


## Interface


### Constructor

- **AnalogKeypad(const uint8_t pin, const uint8_t bits = 10)** constructor, pin is typical A0 etc.
Bits has a default of 10, but need to be set to match the platform.
If bits < 8 then the internal shift would be large causing all reads to return 0 or so.


### polling interface

- **uint8_t pressed()** returns 0 if no key pressed, otherwise returns key pressed (may fluctuate).
- **uint8_t read()** read the key pressed returns 0 .. 16 where 0 means NOKEY.


### event interface

- **uint8_t event()** checks if a change has occurred since last time.
- **uint8_t key()** returns the key involved with last event.

Switch(int e = event()) 
  
| Event    | value |
|:--------:|:-----:|
| PRESSED  | 0x80  |
| RELEASED | 0x40  |
| REPEATED | 0x20  |
| CHANGED  | 0x10  |
| NOKEY    | 0x00  |


## Operation

The simplest usage is to use the **read()** function. 
This will return a 0 (NOKEY) when no key is pressed and
a number 1 to 16 for the keys pressed. Note the return value may
fluctuate randomly when multiple keys are pressed.

The **pressed()** function is a bit more robust.
It returns the key pressed first, so multiple key presses simultaniously 
are less likely to disturb your program.

See Examples


## Future

- more examples
- self-learning example?
- make internal mapping array runtime adaptable?
  - store in RAM, accessor functions
  -