ATxmega have many clock options. This introduce clk_init into cpu_init
to allow user select between a default configuration or perform fine
clock tune.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
The ATxmega can have up to 8 UARTs. This increase from 2 up to 7 to
keep avr8_state flags with 8 bits wide.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
Split atmega_common code into avr8_common folder. This moves common
avr8 code to be used for all avr8 variants: tiny, mega and xmega.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>