RT-Thread/rt-thread: https://github.com/RT-Thread/rt-thread.git @ 85a0aaa3c2dc2f563ca25a91a00c033eddbb78d2

chenchaoqun@rt-thread.com bb8e89e851 【串口】宏定义对应增加		7 gadi atpakaļ
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applications	80a21100b3 remove uart rx code	8 gadi atpakaļ
asflib_config	189c999f8e add atmel SAM D21 bsp support	8 gadi atpakaļ
board	189c999f8e add atmel SAM D21 bsp support	8 gadi atpakaļ
sam_d2x_asflib	62058e18fe [bsp][samd21] update scons script.	7 gadi atpakaļ
README.txt	84f0d9f988 Update README.txt	8 gadi atpakaļ
SAM_D2X_RTT.sct	5b1235f5f5 add scons cmd build	8 gadi atpakaļ
SConscript	189c999f8e add atmel SAM D21 bsp support	8 gadi atpakaļ
SConstruct	189c999f8e add atmel SAM D21 bsp support	8 gadi atpakaļ
project.uvprojx	0f3563fd64 [BSP] Update project files	8 gadi atpakaļ
rtconfig.h	bb8e89e851 【串口】宏定义对应增加	7 gadi atpakaļ
rtconfig.py	62058e18fe [bsp][samd21] update scons script.	7 gadi atpakaļ
template.uvprojx	189c999f8e add atmel SAM D21 bsp support	8 gadi atpakaļ

		
				README.txt
			
				使用SAMD21-Xplained-Pro开发板
scons:
  scons
  scons --target=mdk5
demo代码演示了串口、外部中断、RTC低功耗唤醒