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STR9 USB Enumeration Problem

Steve Ressler

Hello,

I have a MCBSTR9 dev board and have implemented a USB virtual serial port using the example from ST's website. It works fine as long as the jlink JTAG device is plugged in before I plug the board's usb port into my PC. If the jlink device is not plugged in, the device does not enumerate properly. Windows reports a vender and device id of 0x0000, and no driver will load. I have jumper J4 on the board set to ground. Is there a jumper or setting somewhere I am missing? Has anyone experienced this before? Thanks,

-Steve

Parents
  • 0 in reply to Patrick Noonan

    "A device on the bus can draw up to 500mA from it."

    I thought that 500mA was only available after negotiation?

    ie, any "dumb" device can just plug into a USB socket and draw up to 100mA(?) but, if over 100mA(?) is required, the device has to specifically request it using the USB protocol.

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  • 0 in reply to Patrick Noonan

    "A device on the bus can draw up to 500mA from it."

    I thought that 500mA was only available after negotiation?

    ie, any "dumb" device can just plug into a USB socket and draw up to 100mA(?) but, if over 100mA(?) is required, the device has to specifically request it using the USB protocol.

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