BootSwitch.c

#include "pico/stdlib.h"
#include "bsp/board.h"
#include "tusb.h"

// GPIO pin for the boot selector switch
// Switch open / HIGH (pull-up) → Linux   (default=0)
// Switch closed / LOW          → Windows (default=1)
#define SWITCH_PIN 15

// Declared in msc_disk.c
void msc_set_boot_target(bool linux_selected);

int main(void) {
    board_init();

    // Initialize switch GPIO with internal pull-up
    gpio_init(SWITCH_PIN);
    gpio_set_dir(SWITCH_PIN, GPIO_IN);
    gpio_pull_up(SWITCH_PIN);

    // Read initial switch position and configure virtual disk
    bool linux_selected = gpio_get(SWITCH_PIN);
    msc_set_boot_target(linux_selected);

    // Initialize USB
    tusb_init();

    bool last_switch = linux_selected;

    while (true) {
        tud_task();

        // Detect switch change and update grub.cfg on the fly
        bool current = gpio_get(SWITCH_PIN);
        if (current != last_switch) {
            last_switch = current;
            msc_set_boot_target(current);
        }
    }
}