USB is alive again! After fiddling with the FT232RL and the USB cable some combination of factors brought it back to life. I suspect that the cable may have been the problem all along (goes to show that you should always double check what you think works). I ended up using the clips from my USBee and the AVR ISP to test the cable and it passed…after I swapped USBDP/DM (this was after I’d already cut the end off and soldered on new connections, along with heat-shrinking the more sensitive 26/28 gauge cables – I imagine if I had tested it before it would have failed).

Testing the USB cable for continuity/functionality

One thing to note – every time I tested the USB cable with my multimeter for continuity it worked (and that’s from the male plug contacts to the output pin on the wiring harness). What this tells me is a continuity test of a USB cable is not enough to verify it’s functionality (unless there was some freak event where it would have failed continuity if I’d checked at a different time). I’ll have to ask one of my EE friends or a forum about this but it’s something I’m going to keep in mind in the future when dealing with USB.

I didn’t end up connecting the RESET pin to anything, it’s just floating. Hopefully this won’t cause me any issues with enumeration but if I start having issues that’ll be where I start. In v1.1 that will be fixed so let’s hope it holds up until then.

So, this means that all of the hardware on ThumperFI v1.0 is fully functional! There were only two minor modifications  which will also be fixed in v1.1.