arch/arm/include/samd/chip.h

arch/arm/src/samd/Kconfig

arch/arm/src/samd/Make.defs

arch/arm/src/samd/chip/sam_usart.h

arch/arm/src/samd/sam_config.h

arch/arm/src/samd/sam_lowputc.c

arch/arm/src/samd/sam_lowputc.h

arch/arm/src/samd/sam_usart.c

arch/arm/src/samd/sam_usart.h

configs/samd20-xplained/README.txt

configs/samd20-xplained/include/board.h

configs/samd20-xplained/nsh/defconfig

configs/samd20-xplained/src/sam_ug2832hsweg04.c