GUF-Yocto-jethro-9.0-r7707-0
i.MX6
User Manual
do
echo "nameserver $d" >> /etc/resolv.conf
done
;;
stop)
;;
*)
echo "Usage: $0 {start|stop}" >&2
exit 1
;;
esac
To activate this script insert the code into a file in
/etc/init.d/resolv-dns-simple.sh
, mark it as execuatble it and
add it to the runlevel files.
root@santaro:~# chmod ug+x /etc/init.d/resolv-dns-simple.sh
root@santaro:~# update-rc.d resolv-dns-simple.sh defaults
Insert the custrom DNS server according to your needs to the
DNS
variable in the display.
Note:
The settings require a reboot to take effect.
4.2.2 Power down mode
The system can enter a power down mode to reduce power consumption when the system is not in use. In this
mode all PLLs are disabled, CPU voltages are lowered and several hardware components are powered down.
The overall power consumption should be less than 500 mW in this mode but actually depends on the device and
its hardware assembly option.
Power down mode is entered using the following command:
root@santaro:~# echo mem > /sys/power/state
The average time it takes to enter power down mode has been measured 364
5 ms (last byte on UART RX
until voltage drop on VDDSOC).
There are different possibilities to make the system wake up from the power down mode. Wakeup sources have
to be configured before entering power down mode, otherwise the system cannot be woken up.
RTC:
The CPU internal RTC can be configured to wake up the system after a specified time. The following
command wakes the system up at 20 seconds after the command has been executed:
root@santaro:~# echo +20 > /sys/class/rtc/rtc0/wakealarm
RS232/RS485/MDB:
All serial interfaces can be configured to wake up the system on incoming bytes. The
following command wakes the system up as soon as a byte is received on the serial debug port:
root@santaro:~# echo enabled > /sys/class/tty/ttymxc0/power/wakeup
The average time it takes to wake up from power down mode using the serial debug port has been measured
1326
4 ms (first byte on UART RX until last byte on UART TX).
Note:
The first few incoming bytes after and including the wakeup byte might be truncated and not
received by the UART driver.
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