const int dataPin = 2;   /* DS */
const int clockPin = 3;  /* SHCP */
const int latchPin = 4;  /* STCP */

void setup() {
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
}

int cnt=0;
// 0b 1  0  0  0  0  0  0  0  0  0  0  0  0  1  1  1
//    C1 C2 C3 C4 NC NC NC NC R5 R4 R3 R2 R1 NR NR NR

int16_t pattern1 = 0b0010000011110111;
int16_t pattern2 = 0b0110000011101111;
int16_t pattern3 = 0b0010000011011111;
int16_t pattern4 = 0b0010000010111111;
int16_t pattern5 = 0b0111000001111111;

void loop() {
  digitalWrite(latchPin, LOW);
  if(cnt==0) shiftOutManual(dataPin, clockPin, pattern1);
  if(cnt==1) shiftOutManual(dataPin, clockPin, pattern2);
  if(cnt==2) shiftOutManual(dataPin, clockPin, pattern3);
  if(cnt==3) shiftOutManual(dataPin, clockPin, pattern4);
  if(cnt==4) shiftOutManual(dataPin, clockPin, pattern5);
  digitalWrite(latchPin, HIGH);
  delay(5);
  cnt++;
  if(cnt==5) cnt=0;
}

void shiftOutManual(int dataPin, int clockPin, uint16_t val) {
    for (int i = 0; i < 16; i++) {
        int bit = val & (1 << i); // Get the bit at position 'i'
        digitalWrite(dataPin, bit != 0 ? HIGH : LOW); // Set dataPin HIGH if bit is 1, else LOW

        // Pulse the clock pin
        digitalWrite(clockPin, HIGH);
        delayMicroseconds(1); // short delay to ensure the clock pulse is registered
        digitalWrite(clockPin, LOW);
    }
}