We have about 50 Xbee explorer boards in the field and we see a fair number of Com port closures out of the blue. We have to try to reopen the port but it has moved - usually up one port (Com3 is now Com4, for example). I think it is the FTDI driver. I have pinged FTDI but received no reply.
Has anyone else seen this?
While I haven’t used this specific board, I have seen probably a couple thousand FTDI chips hooked to my PC and while each time I plug a new device in it shows up as COMx+1, if I plug the old one back in it shows up in the COMx spot that it use to occupy.
Make sure you’ve got the latest FTDI driver (from their site). While I don’t know specifics of the driver interface to the FTDI part, there is an ID of some sort to differentiate clients on the USB side. There is some overlap of those IDs, as on my last PC I was up to COM1200 or so, there was some recycling of numbers as new FTDI parts were plugged in.
I’m sure you can tailor this with utilities from FTDI.
So what you are reporting is strange, and may be a function of your PC, OS, driver … What I’m reporting is true of Win7 and was also true for XP.
We have tried these on XP and 7 boxes from Acer, Lenovo and others. All of them fail sooner or later. I would guess there isn’t much to the driver or the chip. Seems weird. Maybe it is the USB drawing too much power and getting a brown out. The behavior is quite asynchronous. The port is seen by device manager. Just not available. It requires a power cycle to the PC