[SOLVED] The inner workings of USB.

stf92 · 01-09-2014, 02:40 AM

Hi: I have a program which runs in a microcontroller which communicates with a PC compatible desktop computer via USB. I would like to know which of the data flow types it uses: bulk, interrupt or isochronous. Of course I have the sources. How could I do in order to know? If you need further information I'm ready to give it to you. NOTE: I forgot. Everything is implemented in software. The micro has no USB support builtin.

stf92 · 01-10-2014, 07:38 AM

It was very easy, after all. I plugged the device into one of the machine's USB jacks and ran 'lsusb -v'.

Code:

     Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               4

The answer is given under 'Transfer type'.