USB using FullDuplex stops with VB

Wurlitzer

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 USB· 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 port·before program shutdown but that had no effect.

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

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tellurian

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.

-tellurian

Wurlitzer

Thank you tellurian! I'll give this a try

Wurlitzer

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.