Added serial (UART) driver for Atmel SAM MCU family.
Note:
- Error handling is not implemented
- The driver works only in polling mode, interrupt mode is
not implemented.
Tested on Atmel SMART SAM E70 Xplained board
Origin: Original
Jira: ZEP-1959
Change-Id: I3e770fd1feb2ddf92cf405a9aa17be92eb32e19b
Signed-off-by: Piotr Mienkowski <piotr.mienkowski@gmail.com>