Come up with a way to supply a port option to select between them:
(APort?UCSR0A:UCSR1A)=0x12;
Fails with a lvalue required as left operand of assignment.
or use
if (APort==0)
UCSR0A=0x12;
else UCSR1A=0x12;
Obviously you can't do this with an ISR because they are different vectors.
Any thoughts?