kopia lustrzana https://github.com/espressif/esp-idf
73 wiersze
3.3 KiB
ReStructuredText
73 wiersze
3.3 KiB
ReStructuredText
|
Watchdogs
|
||
|
|
=========
|
||
|
|
|
||
|
|
Overview
|
||
|
|
--------
|
||
|
|
|
||
|
|
Esp-idf has support for two types of watchdogs: a task watchdog as well as an interrupt watchdog. Both can be
|
||
|
|
enabled using ``make menuconfig`` and selecting the appropriate options.
|
||
|
|
|
||
|
|
Interrupt watchdog
|
||
|
|
^^^^^^^^^^^^^^^^^^
|
||
|
|
|
||
|
|
The interrupt watchdog makes sure the FreeRTOS task switching interrupt isn't blocked for a long time. This
|
||
|
|
is bad because no other tasks, including potentially important ones like the WiFi task and the idle task,
|
||
|
|
can't get any CPU runtime. A blocked task switching interrupt can happen because a program runs into an
|
||
|
|
infinite loop with interrupts disabled or hangs in an interrupt.
|
||
|
|
|
||
|
|
The default action of the interrupt watchdog is to invoke the panic handler. causing a register dump and an opportunity
|
||
|
|
for the programmer to find out, using either OpenOCD or gdbstub, what bit of code is stuck with interrupts
|
||
|
|
disabled. Depending on the configuration of the panic handler, it can also blindly reset the CPU, which may be
|
||
|
|
preferred in a production environment.
|
||
|
|
|
||
|
|
The interrupt watchdog is built around the hardware watchdog in timer group 1. If this watchdog for some reason
|
||
|
|
cannot execute the NMI handler that invokes the panic handler (e.g. because IRAM is overwritten by garbage),
|
||
|
|
it will hard-reset the SOC.
|
||
|
|
|
||
|
|
Task watchdog
|
||
|
|
^^^^^^^^^^^^^
|
||
|
|
|
||
|
|
Any tasks can elect to be watched by the task watchdog. If such a task does not feed the watchdog within the time
|
||
|
|
specified by the task watchdog timeout (which is configurable using ``make menuconfig``), the watchdog will
|
||
|
|
print out a warning with information about which processes are running on the ESP32 CPUs and which processes
|
||
|
|
failed to feed the watchdog.
|
||
|
|
|
||
|
|
By default, the task watchdog watches the idle tasks. The usual cause of idle tasks not feeding the watchdog
|
||
|
|
is a higher-priority process looping without yielding to the lower-priority processes, and can be an indicator
|
||
|
|
of badly-written code that spinloops on a peripheral or a task that is stuck in an infinite loop.
|
||
|
|
|
||
|
|
Other task can elect to be watched by the task watchdog by calling ``esp_task_wdt_feed()``. Calling this routine
|
||
|
|
for the first time will register the task to the task watchdog; calling it subsequent times will feed
|
||
|
|
the watchdog. If a task does not want to be watched anymore (e.g. because it is finished and will call
|
||
|
|
``vTaskDelete()`` on itself), it needs to call ``esp_task_wdt_delete()``.
|
||
|
|
|
||
|
|
The task watchdog is built around the hardware watchdog in timer group 0. If this watchdog for some reason
|
||
|
|
cannot execute the interrupt handler that prints the task data (e.g. because IRAM is overwritten by garbage
|
||
|
|
or interrupts are disabled entirely) it will hard-reset the SOC.
|
||
|
|
|
||
|
|
JTAG and watchdogs
|
||
|
|
^^^^^^^^^^^^^^^^^^
|
||
|
|
|
||
|
|
While debugging using OpenOCD, if the CPUs are halted the watchdogs will keep running, eventually resetting the
|
||
|
|
CPU. This makes it very hard to debug code; that is why the OpenOCD config will disable both watchdogs on startup.
|
||
|
|
This does mean that you will not get any warnings or panics from either the task or interrupt watchdog when the ESP32
|
||
|
|
is connected to OpenOCD via JTAG.
|
||
|
|
|
||
|
|
API Reference
|
||
|
|
-------------
|
||
|
|
|
||
|
|
Header Files
|
||
|
|
^^^^^^^^^^^^
|
||
|
|
|
||
|
|
* :component_file:`esp32/include/esp_int_wdt.h`
|
||
|
|
* :component_file:`esp32/include/esp_task_wdt.h`
|
||
|
|
|
||
|
|
|
||
|
|
Functions
|
||
|
|
---------
|
||
|
|
|
||
|
|
.. doxygenfunction:: esp_int_wdt_init
|
||
|
|
.. doxygenfunction:: esp_task_wdt_init
|
||
|
|
.. doxygenfunction:: esp_task_wdt_feed
|
||
|
|
.. doxygenfunction:: esp_task_wdt_delete
|