Argon bricked after communicating over UART

I have two issues.
First is I have been unsuccessful in communicating between an Argon and an Arduino Mega. The Argon is my main controller. It sends requests for state info over serial to which the Arduino is supposed to respond with a list of values.

Second is issue is that I attempted to accomplish the first by wiring the chips as follows:

  • UART1 TX Argon -> RX1 Arduino
  • UART1 RX Argon -> TX1 Arduino
    While power cycling the Arduino, the Particle became unresponsive and now does not show any status LED and is not detectable by my computer. I've looked at the Status LED page as well as info regarding fixing bootloader but it seems that the Argon requires special attention. I've submitted a support ticket. I have spare Particle boards but I am wary of continuing since I'm not sure what caused this error or what I did wrong.

Any advice or explanations would be greatly appreciated.

The Arduino Mega is a 5V board. Connecting it directly via UART serial to an Argon (also Boron, B SoM, Tracker, P2, or Photon 2) will permanently damage the Particle device.

You need a level-shifter between the Mega (5V) and Particle devices (3.3V).


Oh duh. Alright well that answers that problem. I am unable to add a level shifter due to time constraints so I will probably just connect both to a computer over USB and have a computer translate between the two.