Display variable in binary using LEDs

Comments

• pik33 Posts: 2,413

  2012-07-20 04:53 edited 2012-07-20 04:53

  Byte variable can never be 256, a loop end condition can never be met so it is endless loop
  
  This is simply a bug, we don' know if byte variable overflow doesn't cause any side effects, and this kind of programming should be avoided. Better add another loop. This is clean, simple and understandable.
  

  CON
      _clkmode = xtal1 + pll16x
     _xinfreq = 5_000_000
   
  VAR
     byte LED
  
  PUB LedCounter          ' Method declaration
                                
  dira[16..23] := 11_1111   ' Set P16 thru P23 to output
       repeat
         repeat LED from 0 to 255   ' Repeat 256 times, counting forward(substituting 255 for 256 here causes an endless loop)
             outa[16..23] := LED      ' Set display number in binary on LEDs            
             waitcnt(clkfreq/8 + cnt) ' Wait a moment
  
  
• skylight Posts: 1,915

  2012-07-20 04:58 edited 2012-07-20 04:58

  Thanks pik33 for the quick reply, I thought it would be the case but was just wondering if eventually it may cause problems such as an overflow or something like that?
• cavelamb Posts: 724

  2012-07-20 08:08 edited 2012-07-20 08:08

  One small change to display the full 8 bits.
  The "1" in the dira mask need to be a binary number.
  111111 is decimal.
  

  CON
      _clkmode = xtal1 + pll16x
     _xinfreq = 5_000_000
   
  VAR
     byte LED
  
  PUB LedCounter                          ' Method declaration
                                
  dira[16..23] := 111111            ' Set P16 thru P23 to output 
       repeat
         repeat LED from 0 to 255     ' Repeat 256 times, counting forward(substituting 255 for 256 here causes an endless loop)
             outa[16..23] := LED          ' Set display number in binary on LEDs            
             waitcnt(clkfreq/8 + cnt)     ' Wait a moment
  
• mindrobots Posts: 6,506

  2012-07-20 08:20 edited 2012-07-20 08:20

  I bet the forum ate the % sign - it does that sometimes.
  
  Preface the 111111 with % in your code and all should be well.
• cavelamb Posts: 724

  2012-07-20 09:11 edited 2012-07-20 09:11

  mindrobots wrote: »

  I bet the forum ate the % sign - it does that sometimes.
  
  Preface the 111111 with % in your code and all should be well.

  
  
  Holy Cow! It did.
  It also ate a couple of 1's off of the dira mask.
  Thanks for pointing that out.
  
  (I ain't saying it!)
• skylight Posts: 1,915

  2012-07-20 10:11 edited 2012-07-20 10:11

  Phil Pilgrim points out in the "Support for using this forum" section that the advanced text editor messes about with code even if between tags, his suggestion to use the basic text editor works as I found out today.
  One problem is that the post new thread button sends you to the advanced editor but the reply to post button doesn't I ended up having to switch off the advanced editor in settings! I will ask if anything can be done about it in the support section.