This post addresses what I believe is a serious flaw in the Arduino Robot (US Plug).
I purchased three of these robots. They work for a while, then no longer allow uploading new programs. This problem has been reported by others and I have tried all of the suggestions posted on the forum, to fix the problem. None of these solutions have been successful on any of the three robots.
In order to check the fuses and upload a new boot loader, I purchased an AVR ISPMKII tool made by Atmel. It can connect to the Motor Control Boards (bottom PCB) and an UNO with no problem. I am able to read the fuse settings from these devices.
However, I have never been able to connect to any of the Robot Control Boards (bottom PCBs). I thought that it might be because of the upload problem, but the tool would not connect to the third robot, even before the problem occurred.
The problem was investigated using an DSO and a Logic analyzer. I hooked up a logic analyzer to the 6 pin connector and discovered that the SCK and MOSI signal work properly but there is no activity on the MISO signal. I used an ohm meter to verify that the hardware is correct. So what is causing this problem?
One possibility is that all of the Atmega32U4 microprocessor ICs are pre-programmed before being wave soldered to the PCB. It a may be that the firmware has a bug in it. Possibly, the MISO signal is programed as input instead of an output. Because there is no need to test the six pin interface, before the robot has been shipped, the problem has probably gone unnoticed.
I have sent all of this information to the Arduino developers through a Arduino representative, who was very helpful. So far I have received no response after several weeks.
Others have also reported the upload problem. It would be interesting to know how many Arduino Robots have been sold and what percentage of the users have experienced the upload problem, the problem with the six pin interface on the Control Board (top PCB) or both problems.