I have made my own version of an Arduino Mega and I am encountering some issues. Whenever I try to upload any sketch to the Mega, I get the following error message:
avrdude: stk500v2 ReceiveMessage(): timeout
I can upload just fine to the 16u2 as well as the 2560 using ICSP and Nick Gammons Atmega_Board_Programmer sketch. I have the correct board and COM port selected, and the cable, computer, and USB(2.0) port can upload to other Arduino boards just fine.
I have had some other troubles with the board that have been solved, but this issue remains. Please see my Arduino forum post for more details on these issues.
My current guess is that there may some sort of issue with the transmission lines between the 16u2 and the 2560. Here is a picture of the pcb traces. Can anyone look them over to see if there are issues with the traces?
If the traces seem fine, can anyone think of another reason why the upload does not work?