Making a timer, 32.768kHz+555+DT_INT. Good idea?

[financecatalyst]

Thank you very much Darrel. Surely learnt something new in this project.

So, even when variables are getting saved before entering ISR, only lower bit of timer one is getting incremented in that time. Previously I was resetting it again to '0', which I shouldn't do and let it increment to keep it in sync. BUT it does not reach to higher bit of timer1 in such short time, so we only put TMR1H.7=1, which keep everything simple and in sync.

That is why you also said that in my code it does not matter if that statement is in the beginning of the code or end, because the increment does not reach that higher value even after executing some statements in my ISR.

Got it now (Atleast I hope I have this concept cleared FOREVER)

[Darrel Taylor]

Excellent!

Now you really have "Got It".
And described it well.

Cheers,

[financecatalyst]

I made my circuit on my breadboard. It works kind of OK (INT are longer than 1 sec intervals) with TICON=%00001111 the clock still keeps incrementing even when I take out the 32KHz crystal from RC0-RC1.

The clock stops with
TICON=%00001011, seems Interrupts stop happening with this setting. Can someone please put some light on why this could be happening?

[financecatalyst]

Anyone? Should I start a new thread with this problem?

[mackrackit]

Maybe??
Do you have the Watchdog turned off?

[financecatalyst]

Maybe??
Do you have the Watchdog turned off?

Observations:
Watchdog is OFF.I just tried it with 4MHz oscillator, everything works fine. Intervals are 1 sec as expected. I took out the 32kHz crystal while PIC was working, it suddenly increased the speed of counting seconds(I WAS EXPECTING IT TO STOP ENTERING IN ISR) i.e. interrupts started happening a little faster. I inserted the crystal back in, the speed became ideal i.e. 1 sec interrupts.
Two questions now please:
1) Why didn't the Interrupts Stopped when I took the crystal out?
2) Why things get slow when I use 32768 Hz crystal as an oscillator for the PIC as well as the timer? 4MHz for PIC increases the current consumption to 2.5mA which is criminal when running on batteries.

[Darrel Taylor]

Are you saying that you have two 32768 crystals?
The CPU will be running at 8192 hz (FOSC/4).

You might as well run the timer off the main clock then, (saves the power used by the timer1 oscillator), and gives the same accuracy.
T1CON = 1
Reload TMR1H with $11100000, and definitely put it First in the handler.

And change the LCD timing because PBP still thinks it's running at 4mhz.

DEFINE LCD_COMMANDUS 17
DEFINE LCD_DATAUS 1