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Markus
Joined: 30 Oct 2003
Posts: 13
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| 16F877A, TMROIF |
 Posted: Tue Aug 17, 2004 4:42 am |
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Hi,
Does sb. know of a problem with the Timer0 Interrupt Flag (TMR0IF) when set up as RTCC?
I define TMR0 as a RTCC
| Code: |
setup_timer_0(RTCC_EXT_L_TO_H | RTCC_DIV_1);
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to count pulses within a given time (Timer1).
Whenever I start Timer0 and Timer1 to start counting the pulses, TMR0IF is already set. I tried to clear it "by hand" before starting Timer0, but it gets set again immediately.
| Code: |
TMR0IF = 0; // useless???
enable_interrupts(INT_TIMER0);
enable_interrupts(INT_TIMER1);
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My current workaround is to start Timer0, wait until my routine is finished and start it again. In this case it works... But that wastes valuable time. ;-)
I know it's a strange problem. I hope somebody of you can help me out.
Thank you in advance.
Markus |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 17, 2004 11:13 am |
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Post a small but complete test program, which will demonstrate the problem. Also tell us what you are using for your external clock source
for Timer0. |
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Markus
Joined: 30 Oct 2003
Posts: 13
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| Posted: Tue Aug 24, 2004 5:54 am |
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Hi PCM_Programmer,
I don't know if this is complete enough (I can't locate the error myself, so I don't know which part to post).
| Code: |
#int_timer0
void TMR0_isr() {
if (getting_master_speed) master_speed_temp += 255;
}
#int_timer1
void TMR1_isr() {
disable_interrupts(INT_TIMER0);
disable_interrupts(INT_TIMER1);
master_speed = 0x3FF - (master_speed_temp + get_timer0());
getting_master_speed = false;
}
static void get_master_speed() {
disable_interrupts(INT_TIMER0);
disable_interrupts(INT_TIMER1);
getting_master_speed = true;
TMR1Mode = getSpeed;
set_timer0(0);
master_speed_temp = 0;
// ~5.5ms (@12MHz)
set_timer1(49000);
// is 1 and will be 1 at first run
// cleared before second run
TMR0IF = 0;
enable_interrupts(INT_TIMER0);
enable_interrupts(INT_TIMER1);
}
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| PCM programmer wrote: |
Also tell us what you are using for your external clock source for Timer0.
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I'm counting motor increments. The maximum is 300 rpm x 1024 (resolution) x 4 (multiplication) = 1228800 increments/min.
Markus |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 24, 2004 12:56 pm |
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I wanted a full test program that I could drop into MPLAB and compile,
and program into my demo board. I wanted a program that would
test the TMR0IF bit at appropriate times, and say "Right here, at this
line of code, I can tell that the bit is at an incorrect value. Please help
me to discover why this is happening".
You just gave me code fragments.
I wanted to see your #bit declaration for the TMR0IF bit.
It might be incorrect.
Historically, there have been problems with using external clocks
with timer/counters in the 16-series PICs. You might be experiencing
one of the those problems, or it might be something else.
I don't have time to write a test program for you today.
And, I mean a full program, showing all #fuse , #use delay, #include
statements, etc., but also with only just enough code to demonstrate
the problem. You must write the test program. |
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