I don't understand this code!

[Russ Kincaid]

What I mean by "upside down" is: When the programmed output is high, the output actually goes low and when the programmed output is low, it actually goes high. I don't understand that.

Russ

[Pic_User]

Hi Russ,

What I mean by "upside down" is: When the programmed output is high, the output actually goes low and when the programmed output is low, it actually goes high.

We are not trying to give you a difficult time about this inverted waveform thing. It is just difficult to tell what you are seeing on a recurring waveform. Do you have another circuit synchronized with this output? Are you referencing the measurement to the PIC common?
The timing may be difficult to see with a rapidly cycling code. You could change the code to seconds, just to watch the sequence.

It looks like you WANT the output to be HIGH for three time increments and LOW for one. (See attachment.) http://www.picbasic.co.uk/forum/atta...1&d=1178466510
Is the waveform LOW for three time increments and HIGH for one?

-Adam-

[Russ Kincaid]

Hi Russ,



It looks like you WANT the output to be HIGH for three time increments and LOW for one. (See attachment.) http://www.picbasic.co.uk/forum/atta...1&d=1178466510
Is the waveform LOW for three time increments and HIGH for one?

-Adam-

Exactly right. Why does it do that?
BTW, GPIO.0 produces the positive half of an AC signal while GPIO.1 produces the negative half. The result is an AC that reads the same on a true RMS meter or one that reads 0.7 of the peak.

[skimask]

I'm thinking it might be time to post your schematic so we can quit guessing and start fixin' !

[Russ Kincaid]

This is a very simple circuit, and not part of the problem, I believe.

Russ

[skimask]

This is a very simple circuit, and not part of the problem, I believe.

Russ

Turn the LEDs around and connect them to ground.
When you apply a logic 0 to the pin, the pin sinks current and the LED lights...when you apply a logic 1 to the pin, the LED has the same voltage on both sides and doesn't light up...negative logic.
That's why everything is backwards...but it's really not...it's working just as designed.

[Russ Kincaid]

No, No, not working as designed. I know I can turn the LEDs around, but I want to know why I have to do that. I suppose I could write the program to do the opposite of what I want and see what happens.