tmr2 interrupt problem

[mister_e]

Proteus VSM any sim E+457810214

sorry not for me.

Yeah i know those shift register and i know what a shift register is, what i meant is that it would be great if i had them in stock to build the circuit and test it in a real environment.

I'm not a Sim fan... i know a few people using it for all their design and they seems to be more than happy with it.

[ADCON]

Yes, sim programs are expensive. I had a free beta-testversion once, it had still to much bugs to work with, after that came the pay-version.. I also like to life-test also my bankaccount.. it only takes sometimes some more time. But the good side is that when it workt it really works and with sim-programs is that always a question..

Well, Possibli can you tell me the length of a I2Cread/write procedure because I think that it is also to long. When I start the timer after the ISR it will only read the RTC, it never finishes the coldstart.

I did try to set the prescale to 1:16 but it hadn't any good progress. How do I become a timerinterrupt every 8mSec? of 16msec? Maby I can thy that so it works..

[mister_e]

Well the prescaler was already 1:16 at the first post.. hence why you didn't had any better results
Now what you need to do is to use the POSTscaller. if you set the postscaller to 1:2 you'll have a 2mSec*Prescaller int. 8mSec, postscaller 1:4 and so on

        T2CON = %00011010
                'X------- Unimplemented
                '-0011--- postscale 1:4
                '-----0-- Timer2 off
                '------10 prescaler 1:16

seems to work with the second suggestion

// Snip
        ON INTERRUPT GOTO ISR
        PR2 = 124   ' load period register for 2mSec 
        PEIE = 1    ' Enable peripheral interupt
        GIE = 1     ' enable Global interrupt
        TMR2ON = 1  ' TMR2 ON
        GOTO LOOP                

        disable
ISR:
        TOGGLE PORTB.0
        TMR2IF = 0  ' Clear interrupt flag
        resume
        enable
// end snip

[ADCON]

thanks, i just found it myself.

4000000/4/256/16/2=122
osc/4/8bit/precaler/postprescaler=period
1/122=0,008S

4000000/4/256/16/4=61
1/61=0,016S

now try at the code..

[mister_e]

or... easier way... PICMultiCalc, Timer Helper.
http://www.mister-e.org/pages/utilitiespag.html

255-Value listed in the list, and you're in business

Raise your hand those using it.. at least for timer!!!

OK Darrel

[ADCON]

Well, I can use the timer now.
I even added a postscale of 1:16 and a prescale of 1:16 so it's interrupt-frequency was about 15Hz. The segments were blinkin visibly. Even then, when I changed 'resume loop' to 'resume' I had no changing data to my display. Only the var's he already had.

So, somehow there is something wrong with the resume command. And I really don't know what it is...

[mister_e]

Nah there's no issue with RESUME... i'm trying to analyze the whole program here. yeah i TRY.

Try something... comment out the whole none-ISR code, assign a value to the var used in your ISR, and see if there's any problem. You main loop could be anything like a LED blink. Careful with your delays... you're using ON INTERRUPT...

EDIT:
found 2 X 74HC595 on a really old board here, need to test them first...