USB Serial port not recognized

Hi folks,

I have a freeduino v1.22 purchased as a kit from Seeed Studios. I constructed it according to the instructions I found online, and it worked first time!

However, after writing a couple of new sketches to it, it no longer shows up as a USB serial device, on any of my computers - OS X, Linux or Win32. It DOES still execute the last sketch that was uploaded to it, blinking the LED attached to pin 13 on a periodic basis, and the power LED also lights up.

I saw a troubleshooting step in another forum suggesting that I check if the 3.3V supply is present, which would indicate that the USB surface mount chip was still functioning. In my case, that IS still present.

Can anyone suggest where to start trying to figure out why the USB chip is not talking to my PC?

While a lack of 3V3 indicates there is a problem with the USB bridge, having 3V3 is not an indication that it is working.

You could have a problem with the USB lead, try it on something else. You could have a problem with your USB port, does something else work with it. You could have a problem with the drivers, try completely removing them and re installing them. Failing all that the USB bridge is broken.

Hi Mike,

Thanks for the response.

While a lack of 3V3 indicates there is a problem with the USB bridge, having 3V3 is not an indication that it is working.

You could have a problem with the USB lead, try it on something else. You could have a problem with your USB port, does something else work with it. You could have a problem with the drivers, try completely removing them and re installing them. Failing all that the USB bridge is broken.

I have tried with multiple USB leads, I have tried multiple computers and multiple Operating Systems (OS X, Windows, Linux) hoping to trigger the "new hardware" popups or dmesg entries.

None of those resulted in anything encouraging.

What I was hoping for was a pointer to possible solder joints to check, or other components that may be replaced.

So, assuming that the last is correct, that my USB bridge is broken, should I simply get another Arduino, or can I program it successfully using the parallel port? I have built a ParallelProgrammer as described on the Arduino wiki, but am a bit stumped when it comes to actually figuring out how to use it, and how to get something for it to actually write to the device!

Well you can look for cracks and solder dry joints there is probbly not much chance of that.

You can program the arduino with a USB to a serial TTL board.

The USB bridge is difficult to replace because it is a surface mounted component.

A parallel programmer is not really suitable for programming the arduino direct from the user interface. It's main use is to programmed a boot loader into a blank chip.

I think a second board would be useful ,certainly in this case to test the other components. Along the track you will probably find a good use for the second board.

I have a Nokia CA-42 cable, which is a USB to TTL serial cable, so I should be able to make a plan.

If I take off the existing USB2serial chip, which pins are the RX/TX/ground?

Pin 2 of the ATMEGA 168 (or 328) is the RX data so put the data in on this pin, connect this to the output of your cable adapter. Pin 3 is the TX data so it is an output, put that as an input to your cable. It is confusing as some cables have the TX as an input and others have it as an output. It depends on if it is defined as CTE or DTE http://en.wikipedia.org/wiki/Data_terminal_equipment http://en.wikipedia.org/wiki/Data_circuit-terminating_equipment