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usbusb-descriptor

how to assign a USB's device descriptor "BCD device release number"

Here is the code of USB descriptors (device descriptor as an example). I understand those settings except the BCD device release number. I read USB codes for several different projects. Their device release number are all different. What decides the device release number? is there a list?

const unsigned char usb_dev_desc[] = {
    18,
    0x01, // device descriptor
    0x00, 0x02, // USB 2.0
    0x02, // Class CDC
    0x00, // subclass
    0x00, // protocol   
    0x08, // max packet size
    0xd8, 0x04, // VID
    0x0a, 0x00, // PID
    0x00, 0x01, // device release number ????
    0x01, // manuf string
    0x02, // product string
    0x00, // serial number string
    0x01  // no. of configurations
};
Solution

  • I think the producer of the device decides what number this device should have.