Code

Add to the main application source file, outside of any functions:

struct tcc_module tcc_instance;

Copy-paste the following callback function code to your user application:

static void tcc_callback_to_toggle_led(
        struct tcc_module *const module_inst)
{
    port_pin_toggle_output_level(LED0_PIN);
}

Copy-paste the following setup code to your user application:

static void configure_tcc(void)
{
    struct tcc_config config_tcc;
    tcc_get_config_defaults(&config_tcc, TCC0);

    config_tcc.counter.clock_source = GCLK_GENERATOR_1;
    config_tcc.counter.clock_prescaler = TCC_CLOCK_PRESCALER_DIV64;
    config_tcc.counter.period =   2000;
    config_tcc.compare.match[0] =  900;
    config_tcc.compare.match[1] =  930;
    config_tcc.compare.match[2] = 1100;
    config_tcc.compare.match[3] = 1250;

    tcc_init(&tcc_instance, TCC0, &config_tcc);

    tcc_enable(&tcc_instance);
}

static void configure_tcc_callbacks(void)
{
    tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led,
            TCC_CALLBACK_OVERFLOW);
    tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led,
            TCC_CALLBACK_CHANNEL_0);
    tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led,
            TCC_CALLBACK_CHANNEL_1);
    tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led,
            TCC_CALLBACK_CHANNEL_2);
    tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led,
            TCC_CALLBACK_CHANNEL_3);

    tcc_enable_callback(&tcc_instance, TCC_CALLBACK_OVERFLOW);
    tcc_enable_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_0);
    tcc_enable_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_1);
    tcc_enable_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_2);
    tcc_enable_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_3);
}

Add to user application initialization (typically the start of main()):

configure_tcc();
configure_tcc_callbacks();