![]() Either High speed or Low speed or nothing. The mainboard has USB2.0 hubs and USB3.0 hubs. When I increase the capacitor to 15pF or more I suddenly see the device working with Low speed (1.5MHz) or even failing completely (device enumeration failed) The transfer speed is 20 Megabyte/s which is too fast for Full speed. How did I prove that? I connect a USB stick and transfer a big file. When I connect 3.3pF, 6.8pF or 12pF the device will work with High speed. I opened a USB cable and soldered a capacitor between Data+ and Data- like that:īut although I tried several values for the capacitor it did not work. I have to test how a High speed USB device behaves when it runs at Full speed.Īs High speed runs at 480 MHz and Full speed at 12 MHz I thought this would be easy with a "low pass filter" that does not allow the high frequencies to pass and so the host would automatically negociate a slower speed with the device.
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