ISR code problem

[Alistair George]

Hi if I uncomment the lines below, the ISR does not work any ideas? tks vm
<pre><code>
dim T1val as word
dim tadjust as byte
sub clockevent
T1val=64835
' tadjust+=30
' if tadjust>=222 then
' tadjust-=222
' if tadjust>2 then leda
' T1val+=tadjust
TMR1ON = 0
TMR1=0x0
TMR1H = T1val_h
TMR1L = T1val
TMR1ON =1
'end if
end sub
</code></pre>

[Alistair George]

Sorry; drop the ' if tadjust>2 then leda
line.

[Hugh Considine]

Can you post the whole program? It makes troubleshooting easier and much more reliable if I can just copy and paste from the forum into a new text file, and see what GCBASIC does. Also, what is the date on the version of GCBASIC that you're using?

[Alistair George]

Sure, it would be good to be able to PM you, but. Also, I have been having a major problem with oscillator accuracy which is claimed in the book to be 32khz, elsewhere 31 khz then I'm finding it to be more like 25khz!
Hope I've commented the code enough to help:
<pre><code>
#chip 16F690,.031
#config wdt_on, mclre_off,cpd=1,boren=0,cp_off,OSC=LP
'Oscillator control register LFINTOSC/31khz
osccon=b'00001110'
'PU=off,Intedg=Rise,TOCS=internal,TOSE=low-high,PSA 0=int 1=wdt,xxx=PSArateSelect
asm MOVLW b'01001111'
asm option
'Timer1 register
t1con=b'10001101' 'Xtal/32768/4=8192cps (1:1 prescale)'
'Set the pin directions
dir PORTC.0 out
dir PORTC.1 out
dir PORTC.2 out
dir PORTC.3 out
#define ledR PulseOut portc.0, 25 ms 'Pulse LED on/off
#define ledY pulseout portc.1, 25 ms
#define ledA pulseout portc.2, 25 ms
#define ledG pulseout portc.3, 25 ms
dim freqhi,freqlo as word 'var Current sensor data
dim averagehi,averagelo as word 'var Running Average
#define triphi 100
#define triplo 100 'const Trip point

On Interrupt Timer1Overflow call clockevent 'On Interrupt Timer0Overflow call clockevent
On Interrupt Comp1Change call touchroutine
On interrupt ADCReady call ThermoEvent
dim hour,T1val as word
dim T1,mins,secs,count,tadjust as byte
count=0
secs=0
mins=0
hours=0
oscdiv=0
tadjust=0
sw=0
T1=0 '_T1 event
TMR1=0
T1val =65500
TMR1H = T1val_h
TMR1L = T1val
TMR1=1
dir porta.2 out
IntOn 'Go interrupts
main:
clrwdt 'Make sure this is in the loop
'Timer event
'IntOff
if hours<1 & secs<>count then ledg:count=secs 'indicate up to 1 hour secs display
if secs>59 then 'seconds beep
secs=0
mins+=1
repeat 10
PulseOut porta.2,200 us
Wait 200 us
end repeat
end if
if mins>59 then
mins=0
hours+=1
'binary hours clock indicator
if hours.0 then ledr 'set PortC.0 on
if hours.1 then ledy 'set PortC.1 on
if hours.2 then leda 'set PortC.2 on
if hours.3 then ledg 'set PortC.3 on
PortC=0
if hours>15 then hours=0
end if
'IntOn
goto main

sub ShowLeds(in whichleds)
select case whichleds
end sub

sub clockevent
T1val=65160+23 'allow for ISR/clockevent delay
'*******faulty upper code follows
' tadjust+=30
' if tadjust>=222 then
' tadjust-=222
' if tadjust>2 then leda
' T1val+=tadjust
TMR1ON = 0
TMR1=0x0
TMR1H = T1val_h '0xe1 '0xDF
TMR1L = T1val 'T1val '0xb7 '0xFF
Tadjust+=1 'temporary use of tadjust until upper code is fixed
if tadjust>19 then tadjust=0:secs+=1 'inc seconds
TMR1ON =1
'end if
end sub

sub touchroutine
end sub

sub ThermoEvent
end sub
</code></pre>

[Alistair George]

Hmmm dont know why the markup came in different fonts; oh well.
Version of my GCB is 0.9 15/11

[Nobody/Anonymous]

I think the internal 32KHz oscillator is primarily for clocking the watchdog timer, and keeping the processor alive during low power modes. I believe they tell you it can be all over the map, varying from chip-to-chip, with voltage, and with temperature. If you need better accuracy, clock the processor and timer from the internal 4 or 8MHz clock, but even this can only be counted on for about 1% accuracy. If you need better accuracy, you'll have to use an external crystal.

[Alistair George]

Yep, I have figured that - 1% is quite a timing error and thats the best you can get out of the OSCHi. But this still does not figure why the commented code above does not work?

[kent_twt4]

Just guessing here, but suspect there may be a problem when writing to TMR1 register.  Look at:

    T1val =65500
    TMR1H = T1valh
    TMR1L = T1val

T1valh should be T1val_H.  Another way to do this, as explained to me before by Hugh, is to use an alias.  I think this is more flexible way.

    Dim BigVar As Word Alias HighByte, LowByte