esp8266 - LED 不闪烁（移位寄存器 74hc595）

Question

我有一个连接到 nodemcu esp8266 的 74HC595，试图闪烁第一个 LED 并且它不闪烁。然后我用手指触摸闩锁 (12)，LED 开始闪烁。如何解决这个问题？

代码：

int dataPin = D3; //DS
int latchPin = D2; //ST_CP
int clockPin = D1; //SH_CP

int in_data;

void setup() {
  // put your setup code here, to run once:
  pinMode(D1, OUTPUT);
  pinMode(D2, OUTPUT);
  pinMode(D3, OUTPUT);

  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 0b00000001);
    digitalWrite(latchPin, HIGH);
    delay(500);
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 0b00000000);
    digitalWrite(latchPin, HIGH);
    delay(500);
}