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Altera_Forum's avatar
Altera_Forum
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13 years ago

when use 'else' and when use ; ?

Hi.. I am starter in VHDl. I have some questions... What is difference between else and ;? first code use else but when i use ';' instead of 'else' it doesn't work. Do you know why? and s...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

if you put this ; at end it implies end of statement and then you have to repeat that for each value which means drive the signal (a) with different values (multiple drivers) but compiler needs to understand one value to drive (a). If you have multiple drivers then you must have logic to make the compiler understand how to apply each case (priority).

Priority can be either in a process(if else) or outside process e.g. when else as you have done.