CTC Dispatcher Panel Controller

// CTC Panel Controller (simplified)
#include <SPI.h>

const int LATCH_OUT = 10;
const int LATCH_IN = 9;
byte outputs = 0;
byte inputs = 0;

void setup() {
  SPI.begin();
  pinMode(LATCH_OUT, OUTPUT);
  pinMode(LATCH_IN, OUTPUT);
  Serial.begin(9600);
}

void updateOutputs() {
  digitalWrite(LATCH_OUT, LOW);
  SPI.transfer(outputs);
  digitalWrite(LATCH_OUT, HIGH);
}

byte readInputs() {
  digitalWrite(LATCH_IN, LOW);
  digitalWrite(LATCH_IN, HIGH);
  return SPI.transfer(0);
}

void loop() {
  inputs = readInputs();
  // Process switch positions
  // Update signal LEDs
  updateOutputs();
  delay(50);
}