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USB Bus Reset - host or TUSB3410?

DHarmon
Genius 16430 points
Other Parts Discussed in Thread: TUSB3410

In the case where thefirmware is being of downloaded from the host PC to TUSB3410, does the host or the TUSB3410 raise USB bus reset in order to result in normal USB device enumeraiton after firmware downloading?

On page 9, section 3.2.2 of the TUSB3410 data manual, it says: "... the MCU causes a disconnect and reconnect by clearing and setting the CONT bit, ..."

However the comments in the source code device.c file in lines 1350-1368 seems to say the host PC resets the bus.

So which device (host PC or TUSB3410) raises the bus reset in order to result in normal USB device enumeraiton after firmware downloading?

 

 

  • 0
    TI__Intellectual 2995 points

    I think you are referring to two different scenarios.  A USB Device cannot cause a USB reset.  So the answer to your question is that the USB Host always initiates a USB reset.

    Section 3.2.2 refers to the 3410 wanting to use different microcode if there is not a storage device on the I2C to download firmware from.  The disconnect/reconnect is essentially the SW equivalent of pulling the USB cable to cause the Host to reset/re-enumerate the 3410 so that it uses the downloaded firmware after it has been previously loaded by the USB Host.

  • 0 in reply to Wes Ray
    Prodigy 115 points

    How does section 3.2.2 affect me if I have the header infomation - VID/PID/strings/sernum - in the EEPROM, but still want the actual FW to be downloaded from the host?

  • 0 in reply to PaladinSon53
    TI__Intellectual 2170 points

    It won't affect you at all. FW will be used by our VCP driver regardless of the information loaded in the EEPROM. Nevertheless, if you want to use an specific VID/PID, then you must add the proper information in the driver's INF file to get your TUSB3410 implementation installed using our VCP driver.