DroneNet CAN not active, defective?

BotBlox Hardware
2

Thanks for posting.

A few things to check before assuming it’s faulty:

  1. Power Setup
  • DroneNet can be powered from the 5 V input, CAN port, USB, or USART.
    Make sure you’re only using one power source at a time, the 5 V and CAN rails are not power-ORed. Dual-supplying both can cause issues with the CAN circuitry from coming up.
  • Can you confirm the power source you’re using is not current limited? If it is, there can be brownout resets.
  1. CAN Port Details
  • The CAN port is terminated by default with a split termination resistor network.
  • Can you confirm you’re terminating on the other side?
  1. Firmware and Switch
  • After powering up, the STM32’s green/red LED should blink, if it stays solid or dark, the firmware isn’t running (could be a firmware or a hardware issue)
  • A typical powered and idle DroneNet draws about 100 mA @ 5 V. Your reported 90 mA is about right
  • The ethernet switch circuitry is a separate subsystem to the STM32 subsystem (which runs the firmware). So it is possible there’s an issue with the firmware or STM32.
  1. Next Steps
    1. Are you able to reflash DroneNet with the latest firmware using the SWD header?
      There’s a guide here: How to flash BotBlox boards with firmware.
    1. Power it from USB or the 5 V input (not both).
    1. Check for LED activity and retest the CAN lines.

If after reflashing the CAN lines are still fixed (or you don’t have the ability/setup to reflash), please let me know. It is possible that this could just be a faulty unit, but let me know responses first and we can take it from there.