Sx28 Square Wave

Cenlasoft

Hello,
I was given this code by Terry a while ago. This was to create a square wave.

Device SX28, Oschs2, Turbo, OptionX, StackX

Freq 50_000_000

OutPin Pin RA.0 Output

Interrupt NOCODE 434_782 '217 khz

OutPin =~ OutPin
Returnint

Program Start

Start:
End

It works fine but is it possible to sweep a frequency range in this interrupt?
I want to start at 180 khz and end at about 225 khz

How many steps can this code do between the stated range?

Thanks,
Cenlasoft

Bean

You can, but only in certain steps.

With a reload value of 139 you will get (50,000,000 / 139) / 2 = 179856 Hz
With a reload value of 111 you will get (50,000,000 / 111) / 2 = 225225 Hz

Device SX28, Oschs2, Turbo, OptionX, StackX

Freq 50_000_000

OutPin Pin RA.0 Output


reload   VAR BYTE
 
Interrupt NOCODE
  OutPin =~ OutPin
Returnint reload

Program Start

Start:
  FOR reload = 139 TO 111 STEP -1
    PAUSE 1000 ' CHANGES SWEEP SPEED
  NEXT
  GOTO Start
End

Bean.

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Post Edited (Bean (Hitt Consulting)) : 2/25/2009 10:31:26 PM GMT

Cenlasoft

Hello,
Thanks Bean, I will try it tonight
Cenlasoft

Cenlasoft

Hello,
I have been trying Terry's sweep code with no luck. I am sure it me doing something wrong. I used a scope and an LCR circuit to see if I could get to resonance. If I use the interrupt without sweep at one frequency, it works.

Device SX28, Oschs2, Turbo, OptionX, StackX

Freq 50_000_000

OutPin Pin RA.0 Output

reload VAR BYTE

Interrupt NOCODE
OutPin =~ OutPin
Returnint reload

Program Start

Start:
FOR reload = 139 TO 111 STEP -1
PAUSE 1000 ' CHANGES SWEEP SPEED
NEXT
GOTO Start
End

I am trying to get resonance but the square wave produced is not accurate enough.
Thanks for any hints.
Cenlasoft