AVR CDC

anandr84 · Post by **anandr84** » Tue Dec 30, 2008 10:37 am

Hello all

I have this weird problem. I am using AVR CDC and i have a board based on ATMega128.

The AVR CDC in is BUS powered mode.
Now what happens is, when i keep the CDC connected to the board and switch off the board and again when i switch on the board, the hyper terminal is not able to open the com port. I need to then either disable/enable the virtual com port from device manager, or unplug plug the USB cable again. After i do this it works fine again.
Anyone ever faced this issue ?

I am using WIN XP service pack 2.

Grendel · Post by **Grendel** » Wed Dec 31, 2008 2:21 am

The MS virtual com driver is not PnP aware. Lots of problems w/ it (just do a google search). There are even companies offereing replacement drivers (for $$$ tho, eg. Jungo). SP3 contains a newer driver, may help w/ your specific problem.

Guest · Post by **Guest** » Wed Dec 31, 2008 7:12 am

I will look into this possibility too. I was wondering whether it might be a hardware issue ?

Grendel · Post by **Grendel** » Fri Jan 02, 2009 11:22 pm

No. It's a Windows issue, unfortunately.

anandr84 · Post by **anandr84** » Mon Jan 05, 2009 1:02 pm

well, its happening with linux too...
And it never happens when I am using a battery to power the board. Its always a problem when its powered through the mains supply.