what wrong with this code?

Crosswinds · 2010-01-08 21:38

Hello guys!

You probably have seen my other thread with different questions for my slotcar laptimer!

Well, i have this evening begin to dust of my spin-brain, so i have just played around a bit with it.

What Im trying to in this code, start 2 cogs, one that count 1 ms each cycle to a long, and another cog to present this value to the LCD display.

It works great when i dont assign Lane to a new cog, and just run it with passing it over to Lane. (but this aint going to cut it, since im going to have 4 different lane cogs running), and have the "present" running in its own cog.

But when it is in 2 different cogs, it counts to maybe 83 ms and then just freeze up.

Remember that this code does not reflect the finished idea, i just need to freshen up [noparse]:)[/noparse]

stevenmess2004 · 2010-01-08 22:26

Try making the space you allocate for the stacks bigger, especially the stack for present. So replace this

[b]VAR[/b]
  [b]long[/b] Stack[noparse][[/noparse]&#173;9&#093;
  [b]long[/b] Stack2[noparse][[/noparse]&#173;9&#093;
  
  [b]long[/b] millisec

with this

[b]VAR[/b]
  [b]long[/b] Stack[noparse][[/noparse]&#173;100&#093;
  [b]long[/b] Stack2[noparse][[/noparse]&#173;100&#093;
  
  [b]long[/b] millisec

If it works than you can make the 100 smaller until it works again.

MagIO2 · 2010-01-08 23:14

Steve already found your problem, I suppose?!

In your 'present' function you call other functions of the LCD driver and you never know what these functions call themselves, maybe some private functions ... So, giving a stack of 9 longs simply is not enough and the function calls overwrite your millisec variable.

But another thing:

repeat 
  millisec := ++millisec 
  waitcnt (clkfreq / 1000 +cnt)

this is not accurate, as you always wait for 1ms + the execution time of all instructions.

Better is:

waittime := cnt 
repeat 
  millisec++ 
  waittime+=clkfreq/1000
  waitcnt( waittime )

This way you always wait 1ms and the execution time of the instructions is no problem as long as it does not exceed the 1ms.

Post Edited (MagIO2) : 1/8/2010 11:21:56 PM GMT

Crosswinds · 2010-01-09 00:30

Yep steven found it, and i cannot undestand why i didnt find it myself ^^ tired? hehe

And magIO2 thanks for the input about the wait time, that will help me to pinpoint accuracy [noparse]:)[/noparse]

what wrong with this code?

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