Advantech EPC-R3720, User Manual, Page: 28 / 51

RSB-3720 User Manual 40
Step 2: Test (eg. if usb disk is /dev/sda)
3.8 RTC
Step 1: Disable rtc sync service
Step 2: Set system time to current, then write to RTC
Step 3: Set one incorrect time, then read time from RTC to verify
Step 4: Restore the RTC time to system time
3.9 eMMC/SD/SPI flash
3.9.1 Device Routes
eMMC: /dev/mmcblk2
SD: /dev/mmcblk1
QSPI1: /dev/mtd0
3.9.1.1 Test (eg. emmc)
# dd if=/dev/urandom of=data bs=1 count=1024
# dd if=/dev/sda of=backup bs=1 count=1024 skip=4096
# dd if=data of=/dev/sda bs=1 seek=4096
# dd if=/dev/sda of=data1 bs=1 count=1024 skip=4096
# diff data data1
# dd if=backup of=/dev/sda bs=1 seek=4096
root@imx8mprsb3720a1:~# systemctl disable ntpd.service
Removed /etc/systemd/system/multi-user.target.wants/ntpd.service.
root@imx8mprsb3720a1:~# systemctl stop systemd-timesyncd
root@imx8mprsb3720a1:~# systemctl stop ntpdate.service
root@imx8mprsb3720a1:~# date 021710452016 && hwclock -w && date
Wed Feb 17 10:45:00 UTC 2016
Wed Feb 17 10:45:01 UTC 2016
root@imx8mprsb3720a1:~# date 010100002000 && hwclock -r && date
Sat Jan 1 00:00:00 UTC 2000
2016-02-17 10:45:06.00:00
Sat Jan 1 00:00:00 UTC 2000
root@imx8mprsb3720a1:~# hwclock -s && date
Wed Feb 17 10:45:13 UTC 2016
# dd if=/dev/urandom of=data bs=1 count=1024
# dd if=/dev/mmcblk0 of=backup bs=1 count=1024 skip=4096
# dd if=data of=/dev/mmcblk0 bs=1 seek=4096
# dd if=/dev/mmcblk0 of=data1 bs=1 count=1024 skip=4096
# diff data data1
# dd if=backup of=/dev/mmcblk0 bs=1 seek=4096