Win XP Win7 USB problem

[Lion Kwaytaal]

Hi There,

I am struggling with a strange problem, I connect a board with PIC 18F4550 thru USB serial link with an win-XP computer.
USB is running on full speed.
On this computer I have a terminal program running ( Mic Term).
I use the driver generated by flowcode 4, set to com4
I can send messages to my board and it responds back without any problem, it does exactly what it should do.
Now when I do the same but then I run Mic term on a win 7 64bit computer I can send messages and my board responds but the message back is not received by Mic term if there is a few seconds delay. This delay is geneated by the board depending on what action it must do. After this has happend I can still send messages to the board an it keeps responding but no message send back is received by the computer. It looks like win 7 is ignoring the message send back.
On both computers there are no other USB devices than mouse, keyboard and cardreader.
I have looked into the mchpcdc.inf file but I did not see a win 7 64 bit section although win 7 accepts the driver.
Who knows this problem and how to solve this?

[Benj]

Hello,

I take it you are using the USB Serial Flowcode component?

What about if you send a byte back straight away, then process the command and then send another byte. Worth a try.

I think the problem is that a byte is being put into the USB pipeline, the byte for some reason is then never being received and so the USB connection is being flagged as inactive and disabled by Windows.