Multi-Threading

[Melanie]

Ted stop winding people up that are trying to help you. Folks give up their time for free around here. If you don't like an answer then be polite, say "Thank You" to acknowledge the time they may have devoted to potentially a lost cause, and move on.

In case you're not aware... the short answer to your question at Post #1 is Yes.

If yor PIC has ADC, Comparators, CCPM, USART etc the you can SIMULTANEOUSLY perform any or all of those functions whilst doing something else altogether AT THE SAME INSTANT IN TIME. Go do a forum SEARCH, this has been discussed before.

Alternatively you can TIME-SLICE your code... in the simplest form, using your flashing LED for example, say the LED is flashing at a 2Hz rate, you can switch ON your LED, then go do something else for 250mS before you need to devote an instruction to switching it OFF Gee... at 4MHz, that's a shed load of instructions you can carry out whilst that LED is ON, and again when it's OFF. To the casual observer, it will appear as if the PIC is doing multiple tasks.

[peterdeco1]

How would you use the ADCIN command to read the value of a pot while simultaneously doing something else?

[Bruce]

Setup a hardware peripheral like capture, hardware PWM, counter, UART, etc and enable
it. They will all run simultaneously in the background while you're sampling the A/D input.

[Security]

Hello. I am using the instant interrupt routine. I also posess a servo motor like ted,
so I wand to start a pulsout every 20ms. I did this in the tmr0-interrupt routine(tmr0
initialized by OPTION_REG = 1) I am using a 20Mhz quarz.

I think: 20 / 4 = 5Mhz. OPTION_REG means prescaler = 1:1. Means 1/(5,000,000) equals 0.2us.

TMR0 = 8Bit => 256 * 0.2us = 51.2us.

So every 51.2us there will be an interrupt. So

20,000 / 51.2 = 390.625 = 391. So as soon as the interrupt will have occurred 391 times 20ms
should have been passed. I wrote

  main:
   '...do xyz
   counter = 0
   END

  IRRoutine:
   IF counter = 391 THEN
    pulsout servo, duration
   ENDIF
   IF counter > 391 THEN
    counter = 0
   ENDIF
   IF counter < 391 THEN
    counter = counter + 1
   ENDIF
   @ INT_RETURN

But the servo is choppy. What is wrong?

[skimask]

How does this work?

  main:
   '...do xyz
   counter = 0
   END

  IRRoutine:
   IF counter => 391 THEN
    pulsout servo, duration
    counter = 0
   ELSE
    counter = counter + 1
   ENDIF
   @ INT_RETURN

[Security]

Well.

But the servo is still choppy.

I found the reason: Option_reg was wrong. I had a prescaler of 2:1.