USB BUB not uploading/light stays on?

[rando]

hi,

I'm having problems trying to upload a sketch to my rainbowduino with the USB BUB. I'm kinda at a lost here so I'll just fill you in with everything I've done so far!

when I plug it in it flashes a couple really fast flashes then the yellow light shuts off then comes back on and stays on and about 20 seconds later I get the dreaded "not in sync" error?, at this point I should mention that I do get power from it and it does power the sketch that was previously loaded onto it. I decided to hook it up to the arduino and everything works/programs like it normally should. So I know I'm doing something right so I'm off to find the problem

I tried:

~ touching up/re-heating the solder points
~ switching the RSX/TX around.
~ switching ports, going to the advance driver settings and closing the RTS.
~ tried installing the drivers on a fresh computer using the USB BUB as the first hardware.
~ unplug the matrix from the rainbowduino.
~ pressing the reset button.
~ connected a jumper wire to the reset on the USB BUB although the rainbow takes DTR.
and I even talked nice to it telling it that it's not fat just big boned!!


any help would be appreciated.

[rando]

update...

so I played around with it some more and it turns out that if I start to upload the sketch first then plug the USB cable in it will proceed to upload. When I want to upload a new sketch I need to unplug it rinse and repeat the process over again. Not sure if this is how it's supposed to operate but it's better than nothing!

[oz]

This sounds like an issue with the reset circuit / DTR line. Put a meter on the reset pin of the Atmega See if you can see the signal toggle when you up load. You need some kind of pullup resistor on that line so make sure it's pulled up normally.

Trace that signal back to the BUB - and check the soldering on BUB header pin. Also inspect the cap on the top right of the BUB (with programming headers on the right) This is a series cap on the DTR line. See if you see anything fishy there. Also try probing the RX and TX lines at the Atmega chip. But your results indicate that those are probably OK

A useful troubleshooting tool in this regard is a small speaker with a largish 100 to 470 ufd cap in series. You can hear clicks that are really hard to see with a meter, if they're only fast pulses.

Paul