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prescaler won' work on 12f508

salvo
2012-03-02
2013-05-30
  • salvo
    salvo
    2012-03-02

    hi to everybody
    i need to assign a 1/8 prescaler to tmr0
    i used the command "init tmr" (init timer 0 ps0 1/8), but when i compile no error reported but the routine does not work.
    with the same routine if i change the chip and use the 12f675 it work perfectly.
    can some body help me with this?
    thank you very much
    salvo

     
  • kent_twt4
    kent_twt4
    2012-04-06

    Using the baseline PIC's is always a treat =).  Don't have the time to look at the library, but you can try the following code to set the maximum prescaler.  I think option_reg could be used now instead of asm option?, this is some older code.

    movlw   B'01000111' ;bit 7 GPWU 0 = enables wake on pin change
                        ;bit 6 GPPU 0 = enables weak pullups on GP0, GP1, GP3
                        ;bit 0-2 assign prescaler to TMR0 prescale
    asm option
    
     
  • salvo
    salvo
    2012-04-07

    hello kent
    i was close to add a post here
    i solved writing manully the asm code to set the option reg.
    movlw B'11000010'
    option
    also i needed to reset the option reg after every tmr0 clearing, because when you clear tmr0 you clear also the prescaler too.
    now my speed regulator for rc models work perfectly
    thankyou
    Salvo