Darrel Taylor Elapsed Timer

[rwskinner]

I've been through this before but I must be doing something wrong.
My DT Elapsed Timer is incrementing the seconds every 15 seconds.

I'm running a 18F4520 with an External clock of 20 MHZ

I set T1CON = 0 'Main Clock FOSC/4, 1:1 Prescaler .....

In the Elapsed_Int-18 code I verified the constant is 15543... for 100 interrupts per second.

If OSC == 20
TimerConst = 03CB7h
EndIF

What did I miss? Why am I running so slow.

[Darrel Taylor]

Hmmm ~15 seconds.

I would guess that you are actually running on the internal oscillators default of 1mhz.

If FCMEN (Fail-safe Clock Monitor) is enabled, and the external oscillator fails, it automatically switches over to the internal oscillator.
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[rwskinner]

I'll double check that, but if that were the case, wouldn't my baud rates and stuff be off as well on my serial port stuff?

[Darrel Taylor]

Yes it would.
Didn't realize you had serial working along with the problem.
Thought maybe it was just an LCD, which wouldn't be affected.

Do you have other interrupts in the program too?
Something that might be keeping the interrupts locked up for too long?
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[rwskinner]

Yes, I have one other that's for Rx but it grabs a short 8 byte serial string once every 2 seconds.

INCLUDE "DT_INTS-18.bas" ; Base Interrupt System
INCLUDE "ReEnterPBP-18.bas" ; Include if using PBP interrupts
INCLUDE "Elapsed_INT-18.bas" ; Elapsed Timer Routines

ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler RX_INT, _Receive, PBP, yes
INT_Handler TMR1_INT, _ClockCount, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM

@ INT_ENABLE RX_INT ; enable external (INT) interrupts
@ INT_ENABLE TMR1_INT ; enable external (INT) interrupts


15 seconds is a long time and is pretty consistient.

[rwskinner]

I did check, and I do have the following fuses set in my programmer.

Osc = HS, FSCM = on, Brown Out = Enabled,
Low Power Timer1 Osc = Low Power ??? Was default