Once the UART is connected, you can access the shell interface.

[...]
System time was Thu Jan  1 00:00:16 UTC 1970.
Setting the System Clock using the Hardware Clock as reference...
hwclock: RTC_RD_TIME: Operation not permitted
System Clock set. System local time is now Thu Jan  1 00:00:16 UTC 1970.
Starting syslogd/klogd: done
starting pid 329, tty '/dev/ttyS0': '/sbin/getty 115200 ttyS0'

Vivid-Yocto-Distro V0.1 z7213-astro-pp /dev/ttyS0

z7213-astro-pp login: