09-10-2009 06:00 AM
I know this sounds strange, but I would like to program the USB-6216 DAQ to look like a USB 1.1 instrument to my PC rather than USB 2.0. I don't want to have to use a USB 1.1 hub because of the additional power that it draws. I need to run the USB at the slower 12 Mb/s data rate that 1.1 uses. Or if anyone knows how to change the Windows XP driver to only run in the USB 1.1 mode. Any ideas would be appreciated.
09-10-2009 01:15 PM
What is the reason you want to use USB 1.1? Are you hoping that switching to 1.1 will make a measurable impact on power consumption? Are you trying to use some sort of USB 1.1-only extender device that doesn't enumerate as a hub?
Anyway, here are a few ways to make the USB-6216 use USB 1.1:
09-13-2009 06:36 PM
Thanks for your reply. I need to slow down the bus speed because the USB signal needs to pass through a customer's device (a slip ring) that is really not designed for high-speed signals. It works fine for 1.1 (12 Mbps) but not 2.0 (480 Mbps).
Your suggestion to change to 1.1 using the device manager worked ... well, sort of. It works on XP SP2 but not on SP3. Ideally, I would like to change the USB-6216 driver so that the PC thinks it is a USB 1.1 device. That way any PC would work with it. Any idea if this is possible?
Again, thanks for your help.
09-14-2009 08:50 AM
This change would require a low-level code change in the firmware for the device. This code isn't something that can be changed easily and isn't available to customers. I'm surprised that SP3 won't let you disable the USB Enhanced Host Controller, which would do exactly what you are looking for. What happens when you disable it in device manager?
09-14-2009 12:24 PM
Thanks for the reply regarding the USB-6216 low-level code. I guess that rules it out.
Supposedly when the "enhanced" USB host controller is disabled in the device manager the 1.1 controller takes over. But with SP3 sometimes, but not all the time, all of the USB ports get disabled even after rebooting. It may also be a problem with SP2 but I have not seen it happen.
The LED on the USB-6216 OEM board flashes a single blink if it's in the USB 2.0 high-speed mode and a double blink if in the 1.1 full-speed mode. Would you happen to know if this status can be read programmatically? The board is packaged in an enclosure where the LED cannot be seen.
09-15-2009 11:09 AM