I have two Xenons that are wired to a computer using USB to TTL converters both configured for 3.3V operation. The indepedent units are powered by a 12V-5V converter thru their VUSB pin.
One unit uses a generic CH340 converter, and that one works flawlessly.
The other Xenon uses a genuine FTDI cable. On this unit, if I recycle power to the Xenon, the tiny white LCD flashes once but the Xenon never starts. I checked VUSB voltage and it is 5V.
The only way to get the second unit started is to disconnect the FTDI cable from the computer then reconnect it after the unit is powered.
As my knowledge of electronics is limited, I would appreciate the community’s input as to what is going on. I realize a simple solution is to switch to a CH340 solution but FTDI cables are supposedly the standard.