const int dataPinSR1 = 8;
const int latchPinSR1 = 10;
const int clockPinSR1 = 12;

const int dataPinSR2 = 9;
const int latchPinSR2 = 11;

void setup() {
  pinMode(dataPinSR1, OUTPUT);
  pinMode(latchPinSR1, OUTPUT);
  pinMode(clockPinSR1, OUTPUT);

  pinMode(dataPinSR2, OUTPUT);
  pinMode(latchPinSR2, OUTPUT);
}

void loop() {
  byte dataForSR1 = B10101010;
  byte dataForSR2 = B01010101;

  digitalWrite(latchPinSR1, LOW);
  digitalWrite(latchPinSR2, LOW);

  shiftOut(dataPinSR1, clockPinSR1, MSBFIRST, dataForSR1);
  shiftOut(dataPinSR2, clockPinSR1, MSBFIRST, dataForSR2);

  digitalWrite(latchPinSR1, HIGH);
  digitalWrite(latchPinSR2, HIGH);

  delay(500);
}