lpcware

LPC2368 Watchdog Timer

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by hemant on Sun Dec 22 21:07:38 MST 2013
Hi,

I am using LPC2368. It has pretty complex code running with 1 Timer interrupt (100uS continuous) , 2 UART interrupts, 1 SPI Interrupt, 1 USB interrupt and main loop.
Watchdog timer is of 5 sec and is feed in main loop and in different places.

System works well till 2 hrs.

After 2-3 hrs (undefined interval) there is sudden watchdog reset and system goes in error (handled in my code.)

In errata sheet of LPC2368 following is written

Introduction:
The Watchdog timer can reset the microcontroller within a reasonable amount of time if it
enters an erroneous state.

Problem:
After writing 0xAA to WDFEED, any APB register access other than writing 0x55 to
WDFEED may cause an immediate reset.

Work-around:
Avoid APB accesses in the middle of the feedsequence. This implies that interrupts and
the GPDMA should be disabled while feeding the Watchdog.

What is the cause of WDT reset??? that too after 2-3 hrs??
How to find at which point in code WDT reset occures?? I don't have any debugger.

Thanks
Hemant Undale

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