Implement watchdog timer

[GTF]

I would like to implement the watchdog timer of a 18F14K50 (http://ww1.microchip.com/downloads/en/D ... 41350E.pdf) for only the main loop of my code. Config settings in my USB bootloader have the WDT disabled and the postcaler set to 1. My main loop cycles at about 5 kHz. Will adding the code shown in the attached example do the trick to reset the device if the program should hang for greater than 4msec? I have tested the actual program with this added code and it still compiles and runs as expected. I guess I should also check the WD time-out flag (bit 3 of the RCON register) at startup.

[Benj]

Hello,

Your program looks spot on to me.

If you instead wanted to use C code instead of assembler then you would enable the timer like this.

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wdtcon = 1;

And reset the timer like this.

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MX_CLEAR_WATCHDOG;

Shouldn't really matter though as the output hex file will likely be exactly the same either way.

In the Build -> Project Options menu there is a setting under the General Options tab to allow Flowcode to auto clear the watchdog when using millisecond or second delays, just in case you need any large delays or call any components that use them.

[GTF]

Thanks Benj. Will the code I have added at the beginning of the following example work to set a flag in my program if a WD time-out has occurred? Or is there a better way?

[Benj]

Hello,

I might do it using C code but yes it looks fine to me.

C code:

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FCV_WDT_FLAG = ((rcon & 0x08) >> 3);

[GTF]

Thanks. Seems I did not have the asm code to test the WDT reset flag quite right to keep BoostC happy. It compiles OK now. Not certain that I need the backslash to separate the asm lines...I think I read it somewhere in the BoostC manual. It seems to compile the same with or without it.