.. _ecu_reset:

ECU Reset
====================

OpenECU can reset for various reasons. The **put_Reset** block provides an
output flag for the events below. The flag is set to 1 for the event causing
the last reset.

+---------------+------------------------------------------+---------------------------------------------------+
| **Flag**      | **Cause**                                | **How to Debug**                                  |
+===============+==========================================+===================================================+
| power_reset   | Loss of power to the module              | - Check intermittent power connections            |
|               |                                          | - Monitor for voltage drops                       |
+---------------+------------------------------------------+---------------------------------------------------+
| watchdog_reset| Watchdog timeout                         | - Monitor CPU load                                |
|               |                                          | - Verify usage of Kick Watchdog                   |
+---------------+------------------------------------------+---------------------------------------------------+
| access_reset  | Invalid memory access                    |                                                   |
+---------------+------------------------------------------+---------------------------------------------------+
| fp_reset      | Invalid floating-point operation         |                                                   |
+---------------+------------------------------------------+---------------------------------------------------+
| mem_reset     | Memory corruption                        | - Reset or reprogram might solve                  |
|               |                                          | - If persistent, contact OpenECU Support          |
+---------------+------------------------------------------+---------------------------------------------------+
| forced_reset  | Forced reset by application              | - Check Reset block input                         |
+---------------+------------------------------------------+---------------------------------------------------+
| unknown_reset | Other unknown causes                     | - Check for stack overflow                        |
|               |                                          | - Monitor resource usage                          |
+---------------+------------------------------------------+---------------------------------------------------+

If the application can't run long enough to read reset flags, consult
the :ref:`Flash Code Output <flash_code_output>`.

Watchdog Reset
--------------

The ECU has an internal watchdog requiring periodic updates.
The **psc_CpuLoading** block can monitor CPU load. Absent
a **psc_KickWatchdog** block, OpenECU updates the watchdog automatically.

.. note::
   Infinite loops could cause watchdog resets, although unlikely in pure
   Simulink models.

Stack Overflow
--------------

Monitor stack usage with the **psc_StackUsed** block. The default stack size
is 8192 bytes. To change it, see :ref:`How to change the stack size
<stack_size>`.