Can't programm custom arduino board via USB


I have create a custom arduino board with an ATMega328pb and a FT232RL, I have flash optiboot bootloader with a programmer and now i want to programm it via USB but when i click on upload, nothing happend (avrdude: stk500_recv(): programmer is not responding)

I don't know why....


Did you use the Arduino's "burn bootloader", or some other procedure?
Are you using MCUDude's "miniCore"?

I don't see bypass caps on the atmega328b, nor the 2nd ground connection to pin 5...

Yes I use the arduino burn bootloader with Minicore !

I don't understand what you talk about... Bypass caps ? and pin 5 of atmega or ft232rl ?


I could be missing something but I don't see how VUSB gets to +5v.


Thats why I call them Search A Word circuts.

Tom.. :grinning: :+1: :coffee: :australia:

Well I tried to redo everything again:

  • load the bootloader,
  • send programm with programmer
  • send program via usb

Everything works well !

On the other hand, as soon as I unplug the programmer from the arduino board, I can no longer send via usb

OK. Thanks. But that does not explain where +5v is derived. I would have expected something like
VUSB --> Schottky Diode --> +5v (or even a mosfet)

Yes no problem about that I have a Relay for selecting VUSB or +5V don't worry about that


I'me veeeeerrrrryyyyy sorry... I check all my prototype, I have remove the 0.1uF from DTR on FT232RL so arduino IDE can't reset properly before uploading... My bad....

All's good