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DM8148 usb controller stops responding after any of USB certification test mode bit is set

waqas mazhar
Prodigy 10 points

Other Parts Discussed in Thread: TMS320DM8148

Hi TI E2E,

The structure of my workspace includes an RTOS over the custom BSP of TMS320DM8148. Both USB and Function of its OTG port are working fine in normal mode.

From section 18.5 of DM8148 Reference Manual (SPRUGZ8) , i have written a function that can be used to implement test modes of USB (for certification purposes). Using this function, when i switch the mode of USB controller, it gets hanged. Following is the explanation using an example.

USB Function device is converted into TEST_SE0_NAK mode by setting TEST_SE0_NAK bit in the TESTMODE register to 1. Device responds correctly by responding NAK to any valid IN token (section 18.5.1). After few moments, when I try to switch the mode of device to TEST_J or any other test, device controller does not reply i.e. no interrupt is received in ISR of the usb driver. I have to power cycle the device in order to make it operate properly.

So, my Question is Is there any special way to reset a usb controller after it is switched to test mode?

For usb transactional log see the attached images.

Normal usb device behaves as follows.

Thanks,

waqas

  • 0
    TI__Expert 7885 points

    Hi

    This is expected behavior, once musb controller enters into specific test mode, it will continue to be in that test mode till reset. The only way to switch to different test mode is to restart & reinit the controller completely.

    Regards

    Ravi B