// Define the base address for GPIO registers
#define GPIO_BASE 0x40040000

// Define offsets for GPIO registers
#define GPIO_OUTSET_OFFSET 0x04
#define GPIO_OUTCLR_OFFSET 0x08
#define GPIO_OUTXOR_OFFSET 0x0C
#define GPIO_OUT_OFFSET 0x10

// Define GPIO pin 5 (GP5)
#define PIN_5 (1 << 5)

// Pointer to access GPIO registers
volatile unsigned int *gpio_reg = (unsigned int *)GPIO_BASE;

void setup() {
  // Set pin 5 as output
  gpio_reg[GPIO_OUT_OFFSET / 4] |= PIN_5;

  // Initialize serial communication
  Serial1.begin(115200);
  Serial1.println("Hello, Raspberry Pi Pico W!");
}

void loop() {
  // Toggle pin 5
  gpio_reg[GPIO_OUTCLR_OFFSET / 4] = PIN_5; // Turn LED on
  delay(1000);                               // Wait for 1 second
  gpio_reg[GPIO_OUTSET_OFFSET / 4] = PIN_5; // Turn LED off
  delay(1000);                               // Wait for 1 second
}