Fuse problem with WDT

[stevev]

I'm trying to add a WDT to my (almost finished) code, running on a 16F877. I'm using PCM 3.145 and IDE 3.26.

The code works great with the following fuse:
#include <16F877.h>
#fuses HS, NOWDT, NOPROTECT

However. as soon as I change it to:
#fuses HS, WDT, NOPROTECT

The MPU freezes (remains in reset?). This happens whether or not I initialize the WDT timer values with SETUP_WDT().

Any ideas on what I'm doing wrong? It seems like it should be simple but this has me stumped.

Thanks, steve
___________________________
This message was ported from CCS's old forum
Original Post ID: 12059

[PCM programmer]

:=I'm trying to add a WDT to my (almost finished) code, running on a 16F877. I'm using PCM 3.145 and IDE 3.26.
:=
:=The code works great with the following fuse:
:=#include <16F877.h>
:=#fuses HS, NOWDT, NOPROTECT
:=
:=However. as soon as I change it to:
:=#fuses HS, WDT, NOPROTECT
:=
:=The MPU freezes (remains in reset?). This happens whether or not I initialize the WDT timer values with SETUP_WDT().
:=
:=Any ideas on what I'm doing wrong? It seems like it should be simple but this has me stumped.
-----------------------------------------------------------

Do you ever restart the watchdog timer, within your code ?
You need to do that by inserting the following function
in your main loop. Also, set the watchdog period so
that it's long enough that it doesn't time out between
calls to the restart function.

restart_wdt();

See the CCS example file, EX_WDT.C. It's in this folder:
c:\Program Files\Picc\Examples
___________________________
This message was ported from CCS's old forum
Original Post ID: 12060

[stevev]

Thanks, I thought I was resetting it properly but when I put the SETUP_WDT(WDT_576MS); restart_wdt(); line to the start of my main program it works.

I appreciate so much the quick reply. It really is easy!
-steve-
:=:=
:=:=The code works great with the following fuse:
:=:=#include <16F877.h>
:=:=#fuses HS, NOWDT, NOPROTECT
:=:=
:=:=However. as soon as I change it to:
:=:=#fuses HS, WDT, NOPROTECT
:=:=
:=:=The MPU freezes (remains in reset?). This happens whether or not I initialize the WDT timer values with SETUP_WDT().
:=:=
:=:=Any ideas on what I'm doing wrong? It seems like it should be simple but this has me stumped.
:=-----------------------------------------------------------
:=
:=Do you ever restart the watchdog timer, within your code ?
:=You need to do that by inserting the following function
:=in your main loop. Also, set the watchdog period so
:=that it's long enough that it doesn't time out between
:=calls to the restart function.
:=
:=restart_wdt();
:=
:=See the CCS example file, EX_WDT.C. It's in this folder:
:=c:\Program Files\Picc\Examples
___________________________
This message was ported from CCS's old forum
Original Post ID: 12061

[stevev]

Thanks, I thought I was resetting it properly but when I put the SETUP_WDT(WDT_576MS); restart_wdt(); line to the start of my main program it works.

I appreciate so much the quick reply. It really is easy!
-steve-
:=:=
:=:=The code works great with the following fuse:
:=:=#include <16F877.h>
:=:=#fuses HS, NOWDT, NOPROTECT
:=:=
:=:=However. as soon as I change it to:
:=:=#fuses HS, WDT, NOPROTECT
:=:=
:=:=The MPU freezes (remains in reset?). This happens whether or not I initialize the WDT timer values with SETUP_WDT().
:=:=
:=:=Any ideas on what I'm doing wrong? It seems like it should be simple but this has me stumped.
:=-----------------------------------------------------------
:=
:=Do you ever restart the watchdog timer, within your code ?
:=You need to do that by inserting the following function
:=in your main loop. Also, set the watchdog period so
:=that it's long enough that it doesn't time out between
:=calls to the restart function.
:=
:=restart_wdt();
:=
:=See the CCS example file, EX_WDT.C. It's in this folder:
:=c:\Program Files\Picc\Examples
___________________________
This message was ported from CCS's old forum
Original Post ID: 12062