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#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include <stddef.h>
#include "driver/gptimer.h"
#include "driver/gpio.h"
#include "esp_log.h"

#define LED_GPIO 0
#define PERIOD_MS 500
static const char *TAG = "example";

static bool IRAM_ATTR timer_gpt0_isr(gptimer_handle_t timer, const gptimer_alarm_event_data_t *edata, void *user_data)
{
	static int io_state = 0;
	io_state ^= 1;					    
	gpio_set_level(LED_GPIO, io_state); 
    return (true);
}

void timer_gpt0_initialise (int timer_period_ms)
{
    gptimer_handle_t gptimer = NULL;
    gptimer_config_t timer_config = {
        .clk_src = GPTIMER_CLK_SRC_DEFAULT,
        .direction = GPTIMER_COUNT_UP,
        .resolution_hz = 1000000, // 1MHz, 1 tick=1us //
    };
    ESP_ERROR_CHECK(gptimer_new_timer(&timer_config, &gptimer));

    gptimer_event_callbacks_t cbs = { // ISR/callback del timer
        .on_alarm = timer_gpt0_isr,
    };


    gptimer_alarm_config_t alarm_config = {
        .reload_count = 0, // counter will reload with 0 on alarm event
        .alarm_count = timer_period_ms, // period = 500mss @resolution 1MHz
        .flags.auto_reload_on_alarm = true, // enable auto-reload
    };

    ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config));
    ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, NULL));
    ESP_LOGI(TAG, "Enable timer");
    ESP_ERROR_CHECK(gptimer_enable(gptimer));
    ESP_LOGI(TAG, "Start timer");
    ESP_ERROR_CHECK(gptimer_start(gptimer));
}

void app_main(void){

	gpio_set_direction(LED_GPIO, GPIO_MODE_OUTPUT);

	timer_gpt0_initialise(PERIOD_MS*1000); 
	while(1) { 
		vTaskDelay(0.010* configTICK_RATE_HZ); 
	}
}

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        .resolution_hz = 1000, // 1KHz, 1 tick=1ms //