how to generate two signals from two ports at the same time by using p16f84

[bikxsici]

yes i have an advisor teacher but he does not say anything about how i can do it. i guess he just wonder how i find a solution for this project.

i have started usual basic loop without using tmr0, and for a signal it works well but generating second one with different frequencies causes timing problem. i also tried to implement assembler codes in order to have more time space however it did not help me.

at least i want to find a method so as to generate these signals having pulse witdh x8 ( 8,16,..320 mic. sec ). in this program i am trying to use basic timing by using tmr0 and interrupt. i guess i need a 8 micro seconds time period which constant?

thanks a lot


define OSC 10
timer0 var word
timer1 var word

A0 VAR PORTA.0
A1 VAR PORTA.1


on interrupt goto int_timer

OPTION_REG=%00000000
TMR0=255
INTCON=%10100000

TRISA=0
LOW PORTA

timer1=0
timer0=0


enable
main:

goto main

disable
int_timer:

timer0=timer0+1
if timer0=>3 then ' 3 is a random number
timer0=0
toggle a0
else
endif

timer1=timer1+1
if timer1=>10 then ' 10 is a random number
timer1=0
toggle a1
else
endif


INTCON.2=0
TMR0 = 255
resume

end

[bikxsici]

i have tried to obtain accurate time by changing tmr0 and prescaler, but still no answer

[mackrackit]

You have a lot of stuff in the ISR. Take the IF_THEN_ELSE out of the ISR.

[bikxsici]

yes, i have tried it also, i put them in main loop but i could not obtain time accuracy.

[bikxsici]

i need a loop with constant 8 mic. sec. time period and multiplying it with two different variables to obtain to different signal. but how?

[mackrackit]

How fast are you allowed to run the MCU?

[mackrackit]

http://www.picbasic.co.uk/forum/cont....-PICMultiCalc

[bikxsici]

i am allowed to use pic16f84 and 10 mhz crystal. i think this project is impossible, since i have struggled so much, but unfortunately he has a circuit doing that with pic16f84 :0