I've got a simple yet annoying problem - 2 595 shift registers in series, which do what I want from a software perspective. However, pin 7 on the second 595 is permanently on as soon as any signals have been sent. I've tried alternative LEDs, 595 devices, and positions on the breadboard, but it's always the same. Any ideas? Code attached for completeness
const int dataPin = 12; //D6 - 14 Outputs the byte to transfer D6
const int loadPin = 13; //D7 - 12 Controls the internal transference of data in SN74HC595 internal registers
const int clockPin = 15; //D8 - 11 Generates the clock signal to control the transference of data
double xdata = 1;
void setup() {
pinMode(dataPin, OUTPUT);
pinMode(loadPin, OUTPUT);
pinMode(clockPin, OUTPUT);
}
void loop() {
digitalWrite(loadPin, LOW);
shiftOut(dataPin, clockPin, MSBFIRST, 0);
digitalWrite(loadPin, HIGH);
delay(1000);
digitalWrite(loadPin, LOW);
shiftOut(dataPin, clockPin, MSBFIRST, 1);
digitalWrite(loadPin, HIGH);
delay(1000);
}