This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Click here to see
To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

Control LEDs with 74HC595 Shift Register

This example shows how to use the MATLAB® Support Package for Arduino® Hardware to control multiple LEDs with two 74HC595 8-bit serial-in-parallel-out shift registers.

Hardware Requirements

  • Arduino board

  • Sixteen LEDs

  • Two 74HC595 8-bit serial-in-parallel-out shift registers

  • Sixteen 300-1K ohm resistors

  • Breadboard and wires

Hardware Setup

Connect LEDs and 74HC595 shift registers to Arduino hardware:

  • Connect Vcc pin on 74HC595 to 5V pin on Arduino hardware.

  • Connect GND and OE pins on 74HC595 to GND pin on Arduino hardware.

  • Connect DS or SER pin on 74HC595 to digital pin 8 on Arduino hardware.

  • Connect SHCP or SRCLK pin on 74HC595 to digital pin 9 on Arduino hardware.

  • Connect STCP or RCLK pin on 74HC595 to digital pin 10 on Arduino hardware.

  • Connect MR or SRCLR pin on 74HC595 to digital pin 11 on Arduino hardware.

  • Connect an LED through a resistor to each output of Q0-Q7 or QA-QH pins on the two 74HC595 shift registers.

Create Shift Register Object

Create an arduino object, and include the ShiftRegister library.

   a = arduino('COM4','Uno','Libraries','ShiftRegister')
a = 
  arduino with properties:

                  Port: 'COM4'
                 Board: 'Uno'
         AvailablePins: {'D2-D13', 'A0-A5'}
  AvailableDigitalPins: {'D2-D13', 'A0-A5'}
      AvailablePWMPins: {'D3', 'D5-D6', 'D9-D11'}
   AvailableAnalogPins: {'A0-A5'}
    AvailableI2CBusIDs: [0]
             Libraries: {'ShiftRegister'}

Create shift register object, specifying the connected data pin, clock pin, latch pin, and reset pin.

   dataPin = 'D8';
   clockPin = 'D9';
   latchPin = 'D10';
   resetPin = 'D11';
   register = shiftRegister(a,'74HC595',dataPin,clockPin,latchPin,resetPin)
register = 
  ShiftRegister with properties:

           Model: '74HC595'      
         DataPin: 'D8'           
        ClockPin: 'D9'           
        LatchPin: 'D10'          
        ResetPin: 'D11'          

Light Up LEDs

To turn on the LEDs one after another, run the following command,

   sequenceTable = tril(ones(16));
   for count = 1:16
       write(register,sequenceTable(count,:),'uint16');
       pause(0.5);
   end

To turn off all LEDs at once, call reset on the shift register object,

    reset(register);

Clean Up

When the connection is no longer needed, clear the shift register and arduino object.

  clear register a