The meat of the change here is to allow osctune.h to deal with F_CPU defines that end in 'UL' or 'L' (e.g. 12000000UL), as they do (maybe just in some toolchains?) nowadays. The assembler can't handle the letter suffixes, so we create another macro, F_CPU_NUMERIC, with the letters stripped.
I also commented a lot of osctune.h while working out for myself what it did (there are no changes ot the algorithm, just comments).
The meat of the change here is to allow osctune.h to deal with F_CPU defines that end in 'UL' or 'L' (e.g. 12000000UL), as they do (maybe just in some toolchains?) nowadays. The assembler can't handle the letter suffixes, so we create another macro, F_CPU_NUMERIC, with the letters stripped.
I also commented a lot of osctune.h while working out for myself what it did (there are no changes ot the algorithm, just comments).