I will use TCD0 in split mode, to have two 8 bit timers.
It seems that there are some missing definitions in the compiler:
HCNT, LCNT, HPER, LPER.
By looking at the datasheet, I see they live in the same address as the main timer, so I could just use these:
CNTH, CNTL, PERH, PERL.
But my main concern is that I am unsure if I need to access these registers as if they were 16 bit registers (Access low byte, then high byte), or perhaps the micro will know that the timer is split, and thus access the registers independently...