MyVar = 0 ' zero on entry
WHILE INPUTPIN = desired state
PAUSE 500 ' 1/2 second delay
MyVar = MyVar +1
WEND

When it exits just check the value in MyVar.

if i want to store more tan one byte with serin this will work?

serin porta.1,N2400,["A"], var1, var2, var3 'for 3 vars???
Yep.