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PIC16F452 WDT time-out problem

Started by El75 March 22, 2004
Dear Sirs,

I've developed a product on basis of PIC16F442. On some conditions my
unit goes to the SLEEP mode and wake up from the SLEEP on WDT time-out
or on an interrupt. The postscaler,I've taken, is 64, giving us 64 *
18msec = 1.152sec.
I tested it with MPLAB ICE-2000 and found everything is OK. But then I
burned the real chip(I have only PIC16F452) and found that the WDT
time-out is 18mses instead of 1sec as desired, meaning the postscaler
does not work. I don't know how to eat it.
I will be very grateful for any idea or suggestion.

Thank you in advance and best regards.
>I've developed a product on basis of PIC16F442. On some conditions my >unit goes to the SLEEP mode and wake up from the SLEEP on WDT time-out >or on an interrupt. The postscaler,I've taken, is 64, giving us 64 * >18msec = 1.152sec. >I tested it with MPLAB ICE-2000 and found everything is OK. But then I >burned the real chip(I have only PIC16F452) and found that the WDT >time-out is 18mses instead of 1sec as desired, meaning the postscaler >does not work. I don't know how to eat it. >I will be very grateful for any idea or suggestion.
I assume you mean PIC18F442/452. You should make sure the configuration bits are set using assembler directives in your source code. I believe these override the configuration bits settings of the MPLAB IDE.