1.SPI-Blink.ino

1.SPI-Blink

This example demonstrates the use of shift registers as if they were just normal IO pins. The SPI interface is used because it's easy and fast.

Boards: 🛈

AVR, AVR USB, Nano Every, Nano 33 IoT, Nano 33 BLE, UNO R4, Pi Pico, Due, Teensy 3.x, ESP8266, ESP32

Connections

• SS: 74HC595 ST_CP
• MOSI: 74HC595 DS
• SCK: 74HC595 SH_CP

Connect an LED (and series resistor) between the first output of the shift register and ground.

Remember to connect the enable pin of the shift register to ground and the master reset pin to Vcc in order to enable it.

Behavior

This sketch will blink the LED once a second.

Written by PieterP, 2018-09-01 https://github.com/tttapa/Arduino-Helpers

 
#include <Arduino_Helpers.h> // Include the Arduino Helpers library.
#include <AH/Hardware/ExtendedInputOutput/SPIShiftRegisterOut.hpp>
 
// Instantiate a shift register with the SPI slave select pin as latch pin, most
// significant bit first, and a total of 8 outputs.
SPIShiftRegisterOut<8> sreg {SPI, SS, MSBFIRST};
 
const pin_t ledPin = sreg.pin(0); // first pin of the shift register
 
void setup() {
  sreg.begin();            // Initialize the shift registers
  pinMode(ledPin, OUTPUT); // You don't even need this line, since
                           // shift registers are always outputs
}
 
void loop() {
  // Toggle the state of the LED every 1/2 second
  digitalWrite(ledPin, HIGH);
  delay(500);
  digitalWrite(ledPin, LOW);
  delay(500);
}