[avr-gcc-list] port access with avr-gdb

[Rob MacLachlan]

Yes. it is possible to set I/O registers directly using GDB, but it's a 
pain because the port location and format info is #defines in header 
files, and is not known to GDB.  For this reason, I've never done this 
other than as an experiment.  In comparison to the register browser of 
AVRStudio, this is rather lacking.  You have to convert the I/O register 
 number into a data space address, cast it to an appropriate type, then 
assign to it.

I thought of writing some tool to translate the header file into a gdb 
script as a way to get this info into gdb, but never did.  I suppose a 
better solution would be to get this imported as symbol table info somehow.

  Rob