Chipkit UNO and 4067 LED output example

In this example we will connect a 4067 to our Chipkit UNO, at the expense of 5 I/O lines you can get 16 outputs (or inputs)

The HEF4067B is a 16-channel analog multiplexer/demultiplexer with four address inputs (A0 to A3), an active LOW enable input (E), sixteen independent inputs/outputs (Y0 to Y15) and a common input/output (Z). The device contains sixteen bidirectional analog switches, each with one side connected to an independent input/output (Y0 to Y15) and the other side connected to the common input/output (Z). With E LOW, one of the sixteen switches is selected (low-impedance ON-state) by A0 to A3. All unselected switches are in the high-impedance OFF-state. With E HIGH all switches are in the high-impedance OFF-state, independent of A0 to A3. The analog inputs/outputs (Y0 to Y15 and Z) can swing between VDD as a positive limit and VSS as a negative limit. VDD to VSS may not exceed 15 V.

Here is the pinout of the 4067

4067 pinout

You can see depending on the state of pins S0 – S3 determines the output channel pin that is used. So if S0 to S3 are 0 then Channel 0 which is Pin 9 is selected

4067 truthtable

Schematic

Here is a schematic, in this example we only connected 8 sets of LEDs and resistors but its easy to add another 8 from X8 to X15

Chipkit and 4067

Code

The code example only uses 8 LEDs

If you want to use more than 8 change the for loop – chipkitPin < 7

for (int chipkitPin = 2; chipkitPin < 7; chipkitPin++)

[codesyntax lang=”cpp”]

const int channel[] = {2, 3, 4, 5};

//the output pin - mux input
const int outputPin = 6;

void setup() 
{
 // set up all pins as output:
 for (int chipkitPin = 2; chipkitPin < 7; chipkitPin++) 
 {
 pinMode(chipkitPin, OUTPUT);
 }
}

void loop() 
{
 //iterate through the first 8 channels of the multiplexer (change to 16 if you 
 //have 16 LEDs or outputs connected)
 for (int muxChannel = 0; muxChannel < 8; muxChannel++) 
 {
 //set the channel pins based on the channel you want
 //LED on - high - 100 milliseconds delay
 muxWrite(muxChannel);
 digitalWrite(outputPin,HIGH);
 delay(100);
 }
}

void muxWrite(int whichChannel) 
{
 for (int inputPin = 0; inputPin < 4; inputPin++) 
 {
 int pinState = bitRead(whichChannel, inputPin);
 // turn the pin on or off:
 digitalWrite(channel[inputPin],pinState);
 }
}

[/codesyntax]