problem with a variable

stilgar

Hello I am having trouble. I am working on a program block (please note, this is only a small bit in a larger program) that uses the led_pwm.spin.
What I am trying to do is get the variable "maxbright" to start at 0 and increment to 64 and stop. after this block is completed "maxbright" will remain at 64 for all the rest of code that follows.

everything I have tried don't work at all or don't compile.

thanks

Duane Degn

maxbright is a constant not a variable.

If you use a variable (I used "result") you can change its value from zero to maxbright like this.

repeat result from 0 to maxbright
    repeat x from 7 to _numleds-8
      leds[x] := result 
      waitcnt(clkfreq / (rtime1)+ cnt)              ' center LEDs slowly go from 0 to maxbright 64

This will only change the values of leds[7] and leds[8] though.

This will delay after each element of the two "leds" elements are set. If you want to delay after both elements are set you'd want to change the indentation on the waitcnt to this.

repeat result from 0 to maxbright
    repeat x from 7 to _numleds-8
      leds[x] := result 
    waitcnt(clkfreq / (rtime1)+ cnt)              ' center LEDs slowly go from 0 to maxbright 64

If you explain in more detail what you want to do, I (or others) may be able to help more.

Mike G

Give this concept a try

con

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  MAX_BRIGTH = 64
  MS_DELAY   = 100

VAR
  byte luminosity
  byte isMaxBright 

OBJ
  pst           : "Parallax Serial Terminal"

PUB Main
  pst.Start(57600)
  pause(500)

  luminosity~
  isMaxBright := false
  
  repeat
  
    repeat MAX_BRIGTH
      ifnot(isMaxBright)
        luminosity := (++luminosity) // 65
      pst.dec(luminosity)
      pst.char(13)
      pause(MS_DELAY)
      if(luminosity == MAX_BRIGTH)
        isMaxBright := true

PRI pause(ms)  
  waitcnt(((clkfreq / 1_000 * ms - 3932) #> 381) + cnt)
  return

kwinn

Sounds like you are trying to have the led intensity increase slowly to imitate waking up and opening eyes slowly. You can do this by making luminosity a variable and increasing it from 0 to maxbright. The rate at which it increases can be set by the number scans between each step in brightness.

stilgar

kwinn wrote: »

Sounds like you are trying to have the led intensity increase slowly to imitate waking up and opening eyes slowly. You can do this by making luminosity a variable and increasing it from 0 to maxbright. The rate at which it increases can be set by the number scans between each step in brightness.

Yes that whats I am trying to do. Many thanks to Duane Degn for the code it works great.
Now a new problem I need to fix is when the LEDs fad on, they seem to flicker. I think its a timing issue, but not sure.

I have attached all the program code I have done so far. The methood called "Death" , is not finished yet. this block is to slow the sweep speed to stop then fade the LEDs off.

Duane Degn

I think if you change the line:

delay   long  1200   ' Actual PWM carrier, period will be delay * wavemax   orig..600 1200 fer 16

In led_pwm_1.spin to:

delay   long  [B]100[/B]   ' Actual PWM carrier, period will be delay * wavemax   orig..600 1200 fer 16

You should get less flicker.

You might want to try several different values for "delay" to see what looks best.

stilgar

I changed the delay to 100 and froze the program. So I went the other way and 5400 seems to work, still minor flicker but if I go any higher the persistence variable goes wacky

Duane Degn

I would think a smaller delay would give less ficker. Did you try 300 or 600?

kuroneko

Duane Degn wrote: »

I would think a smaller delay would give less ficker. Did you try 300 or 600?

That's not enough time for 16 LEDs (1200 is kind of a safe value, IIRC it could be slightly less). With decay enabled you'd get a [thread=139419]waitcnt lockup[/thread].

stilgar

Thanks, everyone