ESP 32 - Watch dogs

A watchdog(WD) is builtin system which resets your system if you are too late to reset the WD system.

Normally used as last safey system to reboot your system if its running wild.

The watchdog is pregrammed to a time 10,100,1000,2000,4000 msec depending on you system

ESP32 watchdog

/*
   JDN
   watchdog
   if you dont feed the dog you will reboot within <watchdog timeout> time [sec]

      https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/wdts.html

*/
#include <esp_task_wdt.h>
void task1 (void *pParm)
{

  while (1) {
      vTaskDelay(1); // if you comment out vTAskDelay watchtimer will reboot
                     // because you dont tell FreeRTOS you are alive
                     // or disable watchdog on Core0   disableCore0WDT();
  }
}

void setup() {
  Serial.begin(115200);
  delay(1000);

  // change timeout for watchdog esp_task_wdt_init(1, true); // <wd timeout in seconds>,<panic true/false>min 1 sec

  xTaskCreatePinnedToCore(task1, "t0", 2000, NULL,  2, NULL, 0);

  vTaskDelete(NULL); // terminate myself so only task above is running

}

void loop() {}

Documentation

System calls

-  esp_task_wdt_init(WDT_TIMEOUT, true)               enable panic so ESP32 restarts(in sec)
- esp_err_t esp_task_wdt_add(TaskHandle_t handle)     Subscribe a task to the Task Watchdog Timer (TWDT)
- esp_err_t esp_task_wdt_reset(void)                  Reset calling task' the Task Watchdog timer

- esp_err_t esp_task_wdt_delete(TaskHandle_t handle)  Unsubscribes a task from the Task Watchdog Timer (TWDT)
- esp_err_t esp_task_wdt_status(TaskHandle_t handle)  Query whether a task is subscribed to the Task Watchdog Timer (TWDT)
-

System calls - Arduino IDE

Normally you are or should run on core 0, so ues Pinned version of createTask

Arduino hal

disableCore0WDT();
enableCore0WDT();

disableCore1WDT();
enableCore1WDT();

enableLoopWDT();
disableLoopWDT();
feedLoopWDT();

Arduino HAL/WD code (source)

(click for code)

esp32-hal misc
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_attr.h"
#include "nvs_flash.h"
#include "nvs.h"
#include "esp_partition.h"
#include "esp_log.h"
#include "esp_timer.h"
#ifdef CONFIG_APP_ROLLBACK_ENABLE
#include "esp_ota_ops.h"
#endif //CONFIG_APP_ROLLBACK_ENABLE
#ifdef CONFIG_BT_ENABLED
#include "esp_bt.h"
#endif //CONFIG_BT_ENABLED
#include <sys/time.h>
#include "soc/rtc.h"
#include "soc/rtc_cntl_reg.h"
#include "soc/apb_ctrl_reg.h"
#include "rom/rtc.h"
#include "esp_task_wdt.h"
#include "esp32-hal.h"

//Undocumented!!! Get chip temperature in Farenheit
//Source: https://github.com/pcbreflux/espressif/blob/master/esp32/arduino/sketchbook/ESP32_int_temp_sensor/ESP32_int_temp_sensor.ino
uint8_t temprature_sens_read();

float temperatureRead()
{
    return (temprature_sens_read() - 32) / 1.8;
}

void yield()
{
    vPortYield();
}

#if CONFIG_AUTOSTART_ARDUINO

extern TaskHandle_t loopTaskHandle;
extern bool loopTaskWDTEnabled;

void enableLoopWDT(){
    if(loopTaskHandle != NULL){
        if(esp_task_wdt_add(loopTaskHandle) != ESP_OK){
            log_e("Failed to add loop task to WDT");
        } else {
            loopTaskWDTEnabled = true;
        }
    }
}

void disableLoopWDT(){
    if(loopTaskHandle != NULL && loopTaskWDTEnabled){
        loopTaskWDTEnabled = false;
        if(esp_task_wdt_delete(loopTaskHandle) != ESP_OK){
            log_e("Failed to remove loop task from WDT");
        }
    }
}

void feedLoopWDT(){
    esp_err_t err = esp_task_wdt_reset();
    if(err != ESP_OK){
        log_e("Failed to feed WDT! Error: %d", err);
    }
}
#endif

void enableCore0WDT(){
    TaskHandle_t idle_0 = xTaskGetIdleTaskHandleForCPU(0);
    if(idle_0 == NULL || esp_task_wdt_add(idle_0) != ESP_OK){
        log_e("Failed to add Core 0 IDLE task to WDT");
    }
}

void disableCore0WDT(){
    TaskHandle_t idle_0 = xTaskGetIdleTaskHandleForCPU(0);
    if(idle_0 == NULL || esp_task_wdt_delete(idle_0) != ESP_OK){
        log_e("Failed to remove Core 0 IDLE task from WDT");
    }
}

#ifndef CONFIG_FREERTOS_UNICORE
void enableCore1WDT(){
    TaskHandle_t idle_1 = xTaskGetIdleTaskHandleForCPU(1);
    if(idle_1 == NULL || esp_task_wdt_add(idle_1) != ESP_OK){
        log_e("Failed to add Core 1 IDLE task to WDT");
    }
}

void disableCore1WDT(){
    TaskHandle_t idle_1 = xTaskGetIdleTaskHandleForCPU(1);
    if(idle_1 == NULL || esp_task_wdt_delete(idle_1) != ESP_OK){
        log_e("Failed to remove Core 1 IDLE task from WDT");
    }
}
#endif

BaseType_t xTaskCreateUniversal( TaskFunction_t pxTaskCode,
                        const char * const pcName,
                        const uint32_t usStackDepth,
                        void * const pvParameters,
                        UBaseType_t uxPriority,
                        TaskHandle_t * const pxCreatedTask,
                        const BaseType_t xCoreID ){
#ifndef CONFIG_FREERTOS_UNICORE
    if(xCoreID >= 0 && xCoreID < 2) {
        return xTaskCreatePinnedToCore(pxTaskCode, pcName, usStackDepth, pvParameters, uxPriority, pxCreatedTask, xCoreID);
    } else {
#endif
    return xTaskCreate(pxTaskCode, pcName, usStackDepth, pvParameters, uxPriority, pxCreatedTask);
#ifndef CONFIG_FREERTOS_UNICORE
    }
#endif
}

unsigned long IRAM_ATTR micros()
{
    return (unsigned long) (esp_timer_get_time());
}

unsigned long IRAM_ATTR millis()
{
    return (unsigned long) (esp_timer_get_time() / 1000ULL);
}

void delay(uint32_t ms)
{
    vTaskDelay(ms / portTICK_PERIOD_MS);
}

void IRAM_ATTR delayMicroseconds(uint32_t us)
{
    uint32_t m = micros();
    if(us){
        uint32_t e = (m + us);
        if(m > e){ //overflow
            while(micros() > e){
                NOP();
            }
        }
        while(micros() < e){
            NOP();
        }
    }
}

void initVariant() __attribute__((weak));
void initVariant() {}

void init() __attribute__((weak));
void init() {}

bool verifyOta() __attribute__((weak));
bool verifyOta() { return true; }

#ifdef CONFIG_BT_ENABLED
//overwritten in esp32-hal-bt.c
bool btInUse() __attribute__((weak));
bool btInUse(){ return false; }
#endif

void initArduino()
{
#ifdef CONFIG_APP_ROLLBACK_ENABLE
    const esp_partition_t *running = esp_ota_get_running_partition();
    esp_ota_img_states_t ota_state;
    if (esp_ota_get_state_partition(running, &ota_state) == ESP_OK) {
        if (ota_state == ESP_OTA_IMG_PENDING_VERIFY) {
            if (verifyOta()) {
                esp_ota_mark_app_valid_cancel_rollback();
            } else {
                log_e("OTA verification failed! Start rollback to the previous version ...");
                esp_ota_mark_app_invalid_rollback_and_reboot();
            }
        }
    }
#endif
    //init proper ref tick value for PLL (uncomment if REF_TICK is different than 1MHz)
    //ESP_REG(APB_CTRL_PLL_TICK_CONF_REG) = APB_CLK_FREQ / REF_CLK_FREQ - 1;
#ifdef F_CPU
    setCpuFrequencyMhz(F_CPU/1000000);
#endif
#if CONFIG_SPIRAM_SUPPORT
    psramInit();
#endif
    esp_log_level_set("*", CONFIG_LOG_DEFAULT_LEVEL);
    esp_err_t err = nvs_flash_init();
    if(err == ESP_ERR_NVS_NO_FREE_PAGES){
        const esp_partition_t* partition = esp_partition_find_first(ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_NVS, NULL);
        if (partition != NULL) {
            err = esp_partition_erase_range(partition, 0, partition->size);
            if(!err){
                err = nvs_flash_init();
            } else {
                log_e("Failed to format the broken NVS partition!");
            }
        }
    }
    if(err) {
        log_e("Failed to initialize NVS! Error: %u", err);
    }
#ifdef CONFIG_BT_ENABLED
    if(!btInUse()){
        esp_bt_controller_mem_release(ESP_BT_MODE_BTDM);
    }
#endif
    init();
    initVariant();
}

//used by hal log
const char * IRAM_ATTR pathToFileName(const char * path)
{
    size_t i = 0;
    size_t pos = 0;
    char * p = (char *)path;
    while(*p){
        i++;
        if(*p == '/' || *p == '\\'){
            pos = i;
        }
        p++;
    }
    return path+pos;
}

ESP docu by Jens

coop OS on esp32