// Arduino 4035 4-bits shift register
// https://forum.arduino.cc/t/ardduino-4035-4-bits-shift-registor/1299752

// GPIO Pin definitions
#define CLK_PIN 5       // Clock pin connected to CLK of CD4035B
#define J_PIN 9         // Serial J input connected to J of CD4035B
#define K_PIN 10        // Serial K input connected to K of CD4035B
#define PARALLEL_SERIAL_PIN 6  // Parallel/Serial Control
#define TRUE_COMPLEMENT_PIN 7  // True/Complement Control
#define RESET_PIN 8      // Reset pin for CD4035B (if used)

// Function to pulse the clock signal
void pulseClock() {
  digitalWrite(CLK_PIN, HIGH);  // Clock high
  delay(200);                   // Delay to give enough time for data to settle
  digitalWrite(CLK_PIN, LOW);   // Clock low
  delay(200);                   // Delay before next clock cycle
}

void setup() {
  // Set pins as outputs
  pinMode(CLK_PIN, OUTPUT);
  pinMode(J_PIN, OUTPUT);
  pinMode(K_PIN, OUTPUT);
  pinMode(PARALLEL_SERIAL_PIN, OUTPUT);
  pinMode(TRUE_COMPLEMENT_PIN, OUTPUT);
  pinMode(RESET_PIN, OUTPUT); // Setup reset pin

  // Initialize to low state
  digitalWrite(CLK_PIN, LOW);
  digitalWrite(J_PIN, LOW);
  digitalWrite(K_PIN, LOW);
  digitalWrite(PARALLEL_SERIAL_PIN, LOW);  // Serial mode
  digitalWrite(TRUE_COMPLEMENT_PIN, HIGH); // True output mode
  digitalWrite(RESET_PIN, HIGH);           // Ensure the reset is not active

  Serial.begin(115200);
  Serial.println("CD4035B Shift Register Test");
}

// Function to shift data into the register
void shiftSerialData(bool j, bool k) {
  // Write the serial data to J and K
  digitalWrite(J_PIN, j);  // Set J pin
  digitalWrite(K_PIN, k);  // Set K pin

  // Print data being shifted
  Serial.print("Shifting - J: ");
  Serial.print(j);
  Serial.print(" K: ");
  Serial.println(k);

  // Pulse the clock to shift the data into the first stage
  pulseClock();
}

void loop() {
  // Set to serial mode
  digitalWrite(PARALLEL_SERIAL_PIN, LOW);

  // Example: Shift a known pattern (1010) into the register
  shiftSerialData(HIGH, LOW);  // First stage: Set to 1 (J=1, K=0)
  delay(250);                 // Delay for observation
  shiftSerialData(LOW, HIGH);  // Second stage: Set to 0 (J=0, K=1)
  delay(250);
  shiftSerialData(HIGH, LOW);  // Third stage: Set to 1 (J=1, K=0)
  delay(250);
  shiftSerialData(LOW, HIGH);  // Fourth stage: Set to 0 (J=0, K=1)
  delay(1000);

  // Toggle true/complement mode
  digitalWrite(TRUE_COMPLEMENT_PIN, !digitalRead(TRUE_COMPLEMENT_PIN)); // Switch between true and complement mode
  Serial.println("Toggling True/Complement");
  delay(500);  // Wait 5 seconds to observe the result
}