FOR...NEXT strange counting

[mister_e]

OK i'll try another explanation

    For Variable=0 to 255
        Pouet pouet
        next

The test is done at the FOR TO NEXT line, the incrementation is done at NEXT line.
So at the end the value=256... wich is really hard to fit in a BYTE variable. Hence it gives 0

Change your var to a WORD too see what's happen now.

    Repeat
        Pouet Pouet
        Variable = Variable +1
        Until Variable = 255

a Repeat Untill loop do the test at the end... so this why it worked