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Multiplying Ports (Shift Register 74HC595) | NexaLearn IoT Lab | NexaLearn

Advanced Skills35 دقيقة

Multiplying Ports (Shift Register 74HC595)

Control 8 LEDs using only 3 Arduino pins.

Lesson Content

When Arduino's digital pins run out, we use the 74HC595 shift register. It's an IC that receives data as a 'serial train' through one wire (clocked by pulses), then outputs it to 8 parallel outputs simultaneously. You can even chain multiple chips together to control dozens of LEDs.

Components Needed

Arduino Uno74HC595 IC8 ليدات8 مقاومات 220 أوم

Wiring Notes

Requires close attention: Data Pin to 11, Latch Pin to 8, Clock Pin to 12.

Code Example

const int latchPin = 8;
const int clockPin = 12;
const int dataPin = 11;
void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
}
void loop() {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 0b10101010); // إضاءة تبادلية
  digitalWrite(latchPin, HIGH);
  delay(1000);
}

Common Mistakes

Forgetting to connect the MR and OE pins on the chip — MR to 5V and OE to GND for the chip to work as expected.

Next Lesson

Permanent Memory (EEPROM)