Short version: Connect USB cable before connecting GPIB, and leave USB connected and powered.
Long version: On startup, if one of the MCU I/O lines is pulled low, the controller will enter firmware update mode. As it happens, this I/O line is also one of the GPIB bus signals. Some instruments seem to have stronger pull-down on the bus lines than others. The controller may enter firmware update mode, if the USB cable is plugged in while the controller is connected to such an instrument. Since the pull-down is passive, this behavior could happen even if the instrument is powered down when connecting USB. Hope that helps. Regards, Abdul -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matt Ettus Sent: Tuesday, June 03, 2008 5:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Prologix VRBOOT error On Tue, Jun 3, 2008 at 5:03 PM, Prologix <[EMAIL PROTECTED]> wrote: > Hello Matt, > > It appears your Prologix GPIB-USB controller is in firmware update mode. > Please follow these steps: > > 1. Disconnect USB cable and GPIB cable. If the controller is plugged onto an > instrument, unplug it. > 2. Connect USB cable. > 3. Connect GPIB cable, or plug onto instrument. > > Let me know if you have more questions. That seems to fix things. Simply unplugging USB isn't enough -- I have to take it off the instruments as well. How do I keep from getting into that mode in the first place? I need this to work reliably without having to reconnect it several times a day. Matt _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.