Help uploading bootloader to custom ATMEGA2560 using Uno R3

Hi all,

I have made a custom arduino board using an atmega2560 and I'm at the point where I am trying to put the bootloader on it and then load a sketch. However when trying to load the bootloader, I am getting an error about the device signature.

avrdude: Device signature = 0x000000
avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check.

Here is my procedure:

  • Load ArduinoISP sketch to my Uno

  • Connect uno to mega

  • Uno 10 to Mega reset

  • Uno 11 to Mega 51

  • Uno 12 to Mega 50

  • Uno 13 to Mega 52

  • Uno VCC to Mega VCC

  • Uno GND to Mega GND

  • Tools --> Board --> Mega 2560

  • Tools --> Programmer --> Arduino as ISP

  • Tools --> Burn bootloader

I'll attach a screenshot of my PCB.

If there's anything I'm doing wrong, please help!


whole (102 KB)

Post the schematic.

I see from the routing: no decoupling caps on the VCC pins, ICSP socket looks different from the standard:
Pinout seen from above:
Reset 3 4 GND

Vias to go thru the board look very close from the 2nd picture, could be shorting out?

You could have asked for a review here before purchasing boards.

ICSP socket is not standard, I'm just doing it with dupont wires to my arduino. The vias are close, but not touching. Verified with continuity. I should have asked for review, but based on my research this should be fine. The decoupling caps are the only thing, but I do have an output cap from the power reg IC. It's a 10uF between the 5v and gnd. Is this not sufficient? Seems like it's close enough distance-wise to the chip. Would the decoupling caps be causing such a big issue? Either way, I'm using the VCC from my Uno to power it at the moment so it shouldn't even be relevant right?

I wish I could post a helpful schematic, but I never actually organized it and made it look nice in Fritzing. I really just focused on the PCB view. I've uploaded the file in the original post if you want to take a look since I can't seem to upload it to my response here.