I did a bit of searching and I end up with zip.
I like to know how to clear the three timers used in the 16F88, at any time as the program counter in running.
Say I want to reset TMR2 before a certain function.
I cannot seem to find a command that would do this.
Any Ideas any one

Rifaa

 

You should be able to just write the value you want to the timer register

Ex:
MOVLW 0
MOVWF TMR0 //assigns the value of W to TMR0

Or:

CLRF TMR0 //Clears timer and prescaler


You just have to remember this when writing new values to timer registers :

When writing to TMR0, two instruction clock cycles are lost. Often you have a specific time
period you want to count, say 100 decimal. In that case you might put 156 into TMR0
(256 - 100 = 156). However, since two instruction cycles are lost when you write to TMR0
(for internal logic synchronization), you should actually write 158 to the timer.

 

I like to know how to clear the three timers used in the 16F88, at any time as the program counter in running.

User can access the timer via a memory register.

For Timer0 and 2, that's TMR0 and TMR2. To reset/clear the timer value to zero, simply use the PIC instruct CLRF TMR0 and CLRF TMR2.

For timer1, it is a little bit tricky as it is a 16-bit timer. The timer lower 8-bit might rollover to the higher 8-bit while we carrying out the operation.

Of course user can stop the timer first.

If the timer is running, the correct way is to clear the lower 8-bit first and then clear the higher 8-bit.

 

MOVLW 0
MOVWF TMR0 //assigns the value of W to TMR0

Or:

CLRF TMR0 //Clears timer and prescaler

There is no difference except the first takes one extra instruction. Both will clear TMR0 and the counts inside the prescaler.

 

Thanks guy.
I did use the clrf but the watch window did no show a reset.
I will give it a go again.

Rifaa

 

There is no difference except the first takes one extra instruction. Both will clear TMR0 and the counts inside the prescaler.

I know that, I was just showing the op a couple of ways to do it.... but with the MOVLW, the op can assign any value besides 0, to the TMR register, CLRF only clears it.

 

Hi,
For 8-bit timers, you can do like:
Assembler:

CLRF   TMR0
CLRF   TMR2

C:

TMR0 = 0;
TMR2 = 0;

BASIC:

TMR0 = 0
TMR2 = 0

For 16-bit timers, you need to clear both high and low registers, like:
Assembler:

CLRF   TMR1H
CLRF   TMR1L

C:

TMR1H = 0;
TMR1L = 0;

BASIC:

TMR1L = 0
TMR1L = 0

Hope this helps.
Tahmid.