Pulsin to pulsout with up than 4MHZ crystal ?

Hello members.
I'll try to explain my problem in a comprehensive english but don't blame me if my language is not perfect, English is not native for me.

Well, i just wanna do that :

Pulsin a value on a pin and pulsout this value on another pin.
it's okay with a 4Mhz crystal but not with another one :O(

Here is my code :
-=-=-=-=-=-=-=-=-=-=-=-=-=
@ device PIC16F871, HS_osc, wdt_off, pwrt_off, protect_off, bod_on, lvp_off, cpd_off, wrt_off, debug_off

ADCON1 = 7 'Need this to turn off ADC

DEFINE NO_CLRWDT 1 'Do not auto insert watchdog timer
Define OSC 20 'Not important to define in this case but i want
Clear

TRISA = %11111111 'Pins A are in input mode
TRISC = %00000000 'Pins C are in Output mode
PORTC = %00000000 'Clear Port C

Init:
PULSIN PORTA.2,1,ValInPulse 'Measure the pulse who vary from 1ms to 2ms
PULSOUT PORTC.5, ValInPulse 'Output the pulse
GOTO Init 'Do it always
-=-=-=-=-=-=-=-=-=-=-=-=-=

And now, here is is what i don't understand :
I know Pulsin and pulsout depend from the crystal, so, if the pulsin have a 5 times higher resolution with à 20MHZ crystal, it's the same for the pulsout (?) I think i don't have to multiply or divide the pulsin value before i output it via PORTC.5...

May be someone could explain ?

Thanx.

RCtech , Yes you are correct. The commands resolution depends on the oscillator used. So you must multiply or divide the variable accordingly.

Dave Purola,
N8NTA

Hi, RCTech

Assuming DEFINE OSC doesn't interfere with osc speed for pulsin and pulsout, result won't be the same @ 4Mhz and @ 20 MHz. ratio will be 5 , as you tell.
The Valinpulse value will be the same for Pulsin and Pulsout.

Now, as RC is in your pseudo ... RC pulses values are ~ 80 to 220 @ 4Mhz and 400 to 1100 @ 20 Mhz ... okay, but...

@ 4Mhz, you write: Valinpulse var BYTE ....and @ 20 Mhz you MUST write : Valinpulse var WORD !!!

and I didn't see that in your code ...

Also take care, if you ever use DEFINE PULSIN_MAX to allow for the full signal ( 0 AND 1 state duration = full period )

Now, a little Trick seen nowhere :

Always Write : LOW PORTX.Y before a Pulsout statement ... many ununderstandable bugs come from here !!! ( explanation is in High capacitive loads behaviour of PICs ... and the Pulsout way of work )

Alain
30 years of R/C ...

Quote:

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Originally Posted by Acetronics

Hi, RCTech

.../...The Valinpulse value will be the same for Pulsin and Pulsout.

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Okay, i'm not totally wrong ;O)

Quote:

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Originally Posted by Acetronics

@ 4Mhz, you write: Valinpulse var BYTE ....and @ 20 Mhz you MUST write : Valinpulse var WORD !!!

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Whow, i didn't know that little difference !

Quote:

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Originally Posted by Acetronics

.../...
Now, a little Trick seen nowhere :
Always Write : LOW PORTX.Y before a Pulsout statement .../...

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Thanx, i'm just a little bit more intelligent than yesterday, many many thanx.
Now it's half past 3 AM : too late for me to do the tests but tomorrow probably, i'll post a feedback.

And.... Nice to see i'm not the only one froggy here !

Dave, i've tested with multiplying etc (just in case), but, today i'm sure it was a mistake because pulsin & pulsout have the same res. depending the X-tal used so if pulsin have a 5 times ratio at 20Mhz, then, the pulsout too and i don't need to do some corrections by calcs.

I'll come back on the forum tomorrow or next day to tell if it's okay.

RCTech

Back to confirm everything is okay, this stupid ''BYTEs'' are changed for ''WORDs'' now !

Thanx for your help.

If you don't mind me asking what is your application for this?