Watchdog - Cpu Watchdog Control; Bootloader Environment - Kontron PITX-IMX8M User Manual

Copy both image file and checksum file to USB thumb device with EXT2/3/4 or FAT partition. Connect the USB device
to the module carrier.
The following sequence shows how to load both image file and image checksum file into PITX-iMX8M memory and
compare them. In case of success, the "md5sum -a" command will have no output messages as this extensions is
meant to be used in automatic update scripts to check the binary images against their MD5 checksum.
usb start
load usb 0:1 88000000 <image.bin>
load usb 0:1 8a000000 <image.md5>
if md5sum -a 88000000 $ubootsz *88a00000; then
echo 'CRC check passed'
else
echo 'CRC check failed'
fi
7.4.3. Watchdog – CPU Watchdog Control
The "watchdog" command is used to control the i.MX7 CPU internal watchdog. After watchdog has been started
using "watchdog start", the watchdog is kicked periodically by U-Boot to prevent expiration.
Watchdog timeout can be changed at any time. However, it is not possible to stop watchdog
once it has been started.
Syntax:
=> help watchdog
watchdog - start/stop/kick IMX watchdog
Usage:
watchdog <timeout>
watchdog start <timeout> - start watchdog and set timeout
Example:
Start watchdog with 5 seconds timeout and stop kicking watchdog some time later. Board will reset after watchdog
has been expired.
=> watchdog 5
=> watchdog 0

7.5. Bootloader Environment

The bootloader environment is used to control bootloader and OS startup behavior. Environment variables can be
used to control boot timing (e.g. bootdelay), interface properties (e.g. baudrate, ethact) or they define memory
locations where OS images are stored before boot (e.g. loadaddr, fdt_addr). In addition, bootloader shell commands
can be combined to environment scripts.
The redundant bootloader environment is permanently stored in the QSPI flash device at offset 0x0C0000 and
0x0C8000. During bootloader operation, the environment is held in RAM memory and can be modified and written
back to persistent storage.
Bootloader commands to modify the environment are summed up under the "env" command group:
 env default [-f] –a
 env default [-f] var [...]
 env delete [-f] var [...]
 env edit name
 env exists name
- kick watchdog and set timeout (0 = disable kicking)
[forcibly] reset default environment
[forcibly] reset variable(s) to their default values
[forcibly] delete variable(s)
edit environment variable
tests for existence of variable
pITX-iMX8M – Rev. 0.7 Preliminary
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