How do you store 1 to 2ms servo pulses in a variable?

[skimask]

pulsewidth var word

main:
pulsin port-whatever-pin-whatever, 1, pulsewidth '1 if you pulse is active high
pulsewidth = 2000 - pulsewidth
pulsout port-whatever-pin-whatever, pulsewidth
goto main

Of course, this assumes that your max pulse width is 2ms, usually they go a tad bit farther than 2ms (2.5ms is max endpoint on one of my Futaba's). And the 2000 will also depend on how fast your oscillator runs.
And this will (by default), run at the correct frequency, since the pulsin will only activate when you're servo gets a pulse. Then the program will output the 'inverted' pulse, then go back to the start and wait for the next pulse.

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[Acetronics2]

Hi, Skimask

I wonder it was a typo ...

but inverting "formula" is :

Inv.pulsewidth = ( 2*Neutral ) - pulsewidth

so, in µS it's .... ( 2*1500 ) - pulsewidth

Alain

[skimask]

Hi, Skimask
I wonder it was a typo ...
but inverting "formula" is :
Inv.pulsewidth = ( 2*Neutral ) - pulsewidth
so, in µS it's .... ( 2*1500 ) - pulsewidth
Alain

I've been using my bit of 'pseudo-code' for awhile, works for me, but there's also a lot of assumptions (4mhz osc, 1500us perfect center, 2000 perfect endpoint, etc).
I like your bit of code better and I'm going to change my ways of doing those.

[Martin Peters]

But my understanding is that PULSIN and PULSOUT only applies to PORT B.
Is there a way that RC pulses can be read into PORT A?
Can it indeed be done on the PIC16F84 with the PICBASIC compiler?

Appreciate your time and help with this.

[skimask]

But my understanding is that PULSIN and PULSOUT only applies to PORT B.

Where'd you get that info?
PulsIn/PulsOut doesn't have those restrictions.
If the pin can be read, you can use PulsIn.
If the pin can be written, you can use PulsOut.
It's all in the PBP manual.

And are you using PicBasic (PBC) or PicBasicPro (PBP)?
And which version?

[Martin Peters]

That info. was gleaned from "PIC BASIC - An Introduction" (Neil Edwards & Jasper Roberts). Apologies, I thought I'd already stated the compiler is PICBASIC (PBC).
The PULSIN / PULSOUT commands work fine with PORT B, but not with PORT A. I'm looking to store five R/C channels on each of the five Port A pins, before routing them to PORT B.
From the above postings I've learnt how to get the needed servo reverse action (thanks), but how do you get the RC pulse on PORT A when PBC doesn't recognise PULSIN for that port?

[skimask]

Well, we don't know for sure which PIC you're using (you hinted at the 16F84, but never really specified)...but...
As far as PBC, yep, you sure did mention it... I missed it. My bad.
And PBC is limited in that respect, Pin 0 - Pin 7, that's what you get. Maybe Pin 8 will get you PortA.0. I don't know, I don't use PBC.
If you want my advice, get the upgrade to PBP. You'll be MUCH happier in the long run.

Short of that, don't use the pulsin statement ('cause PBC won't let you).
Write your own tight loop to mock pulsin.
Wait for the pin to go high (or low)
Sit in a tight loop counting the passes thru the loop while the pin is high (or low)
Exit when the pin changes again.
Take the loop count, multiply it by the # of us spent in each loop, and you've got your answer...

OR...
Use the pulsin on the PortB, and use a delay loop to send the 'pulsout' on PortA.