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# HC4051

HC4051 is an Arduino library for a HC4051 1x8 channel multiplexer.


## Description

HC4051 is a library to control the CD74HC4051 8 channel
multiplexer / demultiplexer and compatible devices.

The HC4051 allows e.g one analog port read up to 8 different analog channels,
or one digital port to read the state of 8 buttons.


The channel selection is done with four select lines **A, B, C**

The device can be enabled/disabled by the enable line **INH**


#### Compatibles

to elaborate.


#### Related to 

- https://github.com/RobTillaart/HC4051  (1x8 mux)
- https://github.com/RobTillaart/HC4052  (2x8 mux)
- https://github.com/RobTillaart/HC4053  (3x2 mux)
- https://github.com/RobTillaart/HC4067  (1x16 mux)


## Hardware connection

Typical connection is to connect the four **select pins** to four IO Pins of your board.

The optional **enablePin (INH)** must be connected to GND if not used.
This way the device is continuous enabled.

Example multiplexing analog in.

```
        processor                      HC4051
     +-------------+              +-------------+
     |             |              |             |
     |           A |------------->| S0       Y0 |
     |           B |------------->| S1       Y1 |
     |           C |------------->| S2       Y2 |
     |             |              |          Y3 |
     |          E  |------------->| INH      Y4 |
     |             |              |          Y5 |
     |         A0  |<-------------| Y        Y6 |
     |             |              |          Y7 |
     |         GND |--------------| GND      Y8 |
     |             |              | VCC         |
     |             |              |             |
     +-------------+              +-------------+
```


## Interface

```cpp
#include "HC4051.h"
```

#### Core

- **HC4051(uint8_t A, uint8_t B, uint8_t C, uint8_t enablePin = 255)** constructor.
Set the three select pins and optional the enable pin.
If the enablePin == 255 it is considered not used.
- **void setChannel(uint8_t channel)** set the current channel.
Valid values 0..7, this value is not checked, only the lower 3 bits will be used.
- **uint8_t getChannel()** get current channel 0..7.


#### Enable

These functions work only if enablePin is set in the constructor.

- **void enable()** idem.
- **void disable()** idem.
- **bool isEnabled()** idem.
Also returns true if enablePin is not set.


## Future

- keep in sync with HC4067 et.al.


## Support

If you appreciate my libraries, you can support the development and maintenance.
Improve the quality of the libraries by providing issues and Pull Requests, or
donate through PayPal or GitHub sponsors.

Thank you,