How to Reset TMR2? - Electronic Circuits Projects Diagrams Free

Suraj143 · 16th November 2007, 03:04 AM

Hi I have setup TMR2 in the beginning of the program.Now I need to reset TMR2 in the middle of the program by pressing a button.

what i want to know is do I need to write all this lines including PR2 register,pre scaler etc.. or only bsf INTCON,PEIE is enough for reset the TMR2?

Code:

	movlw	.249
	movwf	PR2
	bsf	INTCON,PEIE
	bsf	INTCON,GIE

Pommie · 16th November 2007, 03:39 AM

Just turn it off with bcf T2CON,TMR2ON.

Mike.

Suraj143 · 16th November 2007, 04:17 AM

Oh I see its very simple.Ok I'll turn that TMR2ON bit OFF & ON to make it reset.

Thanks mike.

geko · 16th November 2007, 08:51 AM

Quote:

Oh I see its very simple.Ok I'll turn that TMR2ON bit OFF & ON to make it reset.

Turning the timer off and on won't reset it, it will just stop it with what ever value is in it.

Since it's an 8 bit timer you can just use CLRF TMR2 without stopping it which will clear both the pre and post scalers at the same time.

Suraj143 · 16th November 2007, 09:00 AM

Quote:

Originally Posted by geko

Since it's an 8 bit timer you can just use CLRF TMR2 without stopping it which will clear both the pre and post scalers at the same time.

OMG then I have to setup all PR2 & prescaler lines as well after clearing TMR2.

geko · 16th November 2007, 10:10 AM

No, it's not that bad.

The pre and postscaler ratios aren't changed neither is the value you've already loaded into PR2.

The pre and post scalers are counters themselves. Writing to TMR2 (any value) sets these back to zero automatically.

It's all in the datasheet by the way.

Suraj143 · 16th November 2007, 10:18 AM

Quote:

Originally Posted by geko

The pre and postscaler ratios aren't changed neither is the value you've already loaded into PR2.

I haven't heard this before.

Quote:

The pre and post scalers are counters themselves. Writing to TMR2 (any value) sets these back to zero automatically.

OK I'll add clrf TMR2 after pressing the button in the coding.

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16th November 2007, 03:04 AM	(permalink)
Suraj143	How to Reset TMR2? Hi I have setup TMR2 in the beginning of the program.Now I need to reset TMR2 in the middle of the program by pressing a button. what i want to know is do I need to write all this lines including PR2 register,pre scaler etc.. or only bsf INTCON,PEIE is enough for reset the TMR2? Code: movlw .249 movwf PR2 bsf INTCON,PEIE bsf INTCON,GIE

16th November 2007, 03:39 AM	(permalink)
Pommie	Just turn it off with bcf T2CON,TMR2ON. Mike.

16th November 2007, 04:17 AM	(permalink)
Suraj143	Oh I see its very simple.Ok I'll turn that TMR2ON bit OFF & ON to make it reset. Thanks mike.

16th November 2007, 10:10 AM	(permalink)
geko	No, it's not that bad. The pre and postscaler ratios aren't changed neither is the value you've already loaded into PR2. The pre and post scalers are counters themselves. Writing to TMR2 (any value) sets these back to zero automatically. It's all in the datasheet by the way. __________________ Pete picprojects.org.uk