This is an Arduino library for interfacing the 74HC4067 multiplexers/demultiplexers.
MUX74HC4067(uint8_t en, int8_t s0, int8_t s1 = -1, int8_t s2 = -1, int8_t s3 = -1);Class constructor. en is the Arduino pin to which the EN pin connects. s0-s3 are the Arduino pins to which the S1-S3 pin connects. The use of S1-S3 is optional. If not used, they should connect to either VCC or GND depending on what range of channels is used.
void setChannel(int8_t pin, uint8_t set = ENABLED);It selects a channel and connects it to the SIG pin by default. The second argument is optional. If the DISABLED constant is given as a 2nd argument, it selects the requested channel, but it doesn't enable the connection to the SIG pin.
void enable();It enables the connection of the SIG pin with a channel that was set earlier by calling either setChannel or write.
void disable();It disables the connection of the SIG pin with a channel that was set earlier by calling either setChannel or write.
void signalPin(uint8_t sig, uint8_t mode, uint8_t type = DIGITAL);It configures how the SIG pin is going to be regarded. Where will it connect to? Will it be an INPUT or an OUTPUT to the Arduino? Is it going to communicate ANALOG or DIGITAL signals? In the argument list, one should specify the Arduino pin to which the SIG pin connects, the mode of that pin, either INPUT, or OUTPUT, or INPUT_PULLUP, and the type of the signals to handle, either ANALOG or DIGITAL.
int16_t read(int8_t chan_pin = -1);It reads from a channel. It's always used after a call to signalPin. It has an optional argument. To use it without an argument, the setChannel method has to have been called earlier (it will read from that specified channel). If the signal pin was set to DIGITAL, read returns HIGH or LOW. If the signal pin was set to ANALOG, read returns the value read by the ADC. If read is called with argument the channel from which to read and setChannel was called earlier, read won't make any changes on that configuration (#channel and ENABLED/DISABLED).
uint8_t write(int8_t chan_pin, uint8_t data, int8_t type = -1);It writes to the requested channel. If the signal pin was set to DIGITAL, data should be HIGH or LOW. If the signal pin was set to ANALOG, write outputs a PWM signal, and data should be the signal's duty cycle. There is an optional argument, it's either ANALOG or DIGITAL, that overrides the configuration set for the signal pin... e.g. if the signal pin was set to DIGITAL OUTPUT, it can still output a PWM signal by providing to write as a 3rd argument, the constant ANALOG.
There are five accompanying examples with the library that demonstrate some basic functionality.