View Full Version : USB using FullDuplex stops with VB

03-16-2009, 03:16 AM
When my Propeller program is launched the USB port sends and receives data fine from a VB application I created. If however I stop the VB application and then start the VB application up again the USBˇ port will not respond. The same thing happens with HyperTerminal. I must restart the Propeller application.

There does not seem to be a problem if the Propeller program is running for a while then I launch either VB or HyperTerminal only if shut down then restarted.

In my VB application I tried shutting down the comm portˇbefore program shutdown but that had no effect.

Any way to keep the USB port functional when the terminal application may have to be restarted?


03-16-2009, 03:36 AM
This is normal because the USB port is used to install new software too, so it does a reset every time it is connected on the assumption that there is a download on the way. What I do is put a switch between the USB port' DTR and the reset pin of the propeller (actually between the transistor off the USB's DTR and the Prop). That way I just switch out this bootload mechanism when I know I just want to connect.


03-16-2009, 04:24 AM
Thank you tellurian! I'll give this a try

03-20-2009, 07:14 PM
UPDATE: In VB you can set the MSComm object's "DTREnable" attribute to "FALSE" and then opening and closing the VB application will not cause the Propeller to reboot. This is a big help when in development mode and certainly after the application is up and running.