nobo...@web.de wrote:
yes, you should use something like a mutex but if you modify a global
variable in a ISR that variable must be volatile. Most commercial
it's not a "must" in many cases. on function entry, all variables are
loaded from RAM anyway (except for functions that are inlined). so, if
you don't need to detect changes on the varaible within a loop, you can
often get away without volatile.
but as Rolf points out, declaring a variable as volatile (that is used
from ints and main) is a good idea and you're on the safe side.
compilers like the ones from IAR do handle every variable as volatile
but gcc does not. ANSI allows both versions.
Without volatile the code is less portable.
Rolf
