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USB Watchdog

Tags: Adapter Auto Restarter USB WatchDog do koparki BTC

Communication protocol

[238947.892900] usb 1-3.4: Product: USB2.0-Serial
[238947.899333] ch341 1-3.4:1.0: ch341-uart converter detected
[238947.906552] usb 1-3.4: ch341-uart converter now attached to ttyUSB0

Serial port parameters: 9600 8N1 

stty -F /dev/ttyUSB0 raw speed 9600

Each command is 1 byte value. It set watchdog threshold in deciseconds. Example commands: Commands sent to watchdog (1 byte):

  • 1 - next expected kick in 10 seconds. 
     echo -ne "\x01" > /dev/ttyUSB0
  • 36 - next expected kick in 360 seconds. 
     echo -ne "\x01" > /dev/ttyUSB0
  • 128 - status query. It responds with 0x81 
     echo -ne "\x80" > /dev/ttyUSB0
  • 255 - forced reset. 
     echo -ne "\xFF" > /dev/ttyUSB0

REMARK: Avoid low threshold. It is stored internally in watchdog, so after reset it is still low. In this case it is not possible to boot OS.

Daemon

https://github.com/niziak/usb-watchdog