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TUSB2046 - not responding

Paweł Krzyżanowski
Prodigy 190 points
Other Parts Discussed in Thread: TUSB2046B

I have been trying to make TUSB2046 working, but yet no effects.

1st of all I read almost all threads about issues with this chip, modify my scheme even as ppl suggested and still not working.
I am using this chip on bigger scheme, but because it is not responding I am trying to build minimal scheme (minimal.pdf) in which TUSB2046 will be detected by PC.
I pull up all OVRCUR pins and pull down all DP/DM pins (except upstream). The power up sequence meet datasheet requirements (rst.bmp -> yellow power | white Reset | blue XTAL (6MHz if I zoom it). What's wrong still?

I can see that if I power this, after few try's of comunicate PC<->chip TUSB2046 go into suspended mode (pull it HI, and disable XTAL), but If I don't connect RESET to output from comparator it doesn't go into suspended mode and crystal is oscillating as long as I don't pull RESET HI. But no matter what I do I can't communicate with it.

Log when connected to PC:
[19600.068053] usb 7-1: new low-speed USB device number 15 using uhci_hcd
[19600.192048] usb 7-1: device descriptor read/64, error -71
[19600.416036] usb 7-1: device descriptor read/64, error -71
[19600.632045] usb 7-1: new low-speed USB device number 16 using uhci_hcd
[19600.752053] usb 7-1: device descriptor read/64, error -71
[19600.976048] usb 7-1: device descriptor read/64, error -71
[19601.192053] usb 7-1: new low-speed USB device number 17 using uhci_hcd
[19601.600029] usb 7-1: device not accepting address 17, error -71
[19601.712053] usb 7-1: new low-speed USB device number 18 using uhci_hcd
[19602.120028] usb 7-1: device not accepting address 18, error -71
[19602.120075] hub 7-0:1.0: unable to enumerate USB device on port 1




minimal.pdf

  • 0
    TI__Mastermind 18655 points

    Hello Paweł, 

    Was the Log taken with the pull-up resistor on the DM0 line instead of the DP0 line as in your schematics?

    According to the Log, the USB host is trying to enumerate the TUSB2046B as a low-speed USB device. 

    Full-speed and low-speed devices are differentiated by the position of the pull-up resistor:

    Full-speed devices are terminated with the pull-up resistor on the D+ line. 
    Low-speed devices are terminated with the pull-up resistor on the D- line.

    Could you check whether the DP0 and DM0 lines are connected correctly on the board?

    Regards,
    Joel

  • 0 in reply to Joel Jimenez0
    Prodigy 190 points

    I paste wrong log. As you said with low-speed, but if I connect as a full-speed there still same error

    [  232.696037] usb 8-1: new full-speed USB device number 2 using uhci_hcd

    [  232.816032] usb 8-1: device descriptor read/64, error -71

    [  233.040036] usb 8-1: device descriptor read/64, error -71

    [  233.256034] usb 8-1: new full-speed USB device number 3 using uhci_hcd

    [  233.376045] usb 8-1: device descriptor read/64, error -71

    [  233.600036] usb 8-1: device descriptor read/64, error -71

    [  233.816034] usb 8-1: new full-speed USB device number 4 using uhci_hcd

    [  234.224017] usb 8-1: device not accepting address 4, error -71

    [  234.336033] usb 8-1: new full-speed USB device number 5 using uhci_hcd

    [  234.744023] usb 8-1: device not accepting address 5, error -71

    [  234.744061] hub 8-0:1.0: unable to enumerate USB device on port 1


    With microscope I can see that both DP0 and DM0 lines are connected correctly and when I probe it with osciloscope I see that some communication is started:

  • 0 in reply to Paweł Krzyżanowski
    TI__Mastermind 18655 points

    Hello,

     It appears that it is related to the power-up sequence.

    1. The power rail should be 3.3v stable.

    2. The oscillator must be 100% stable when reset is de-asserted.

    3. Increase the power on reset pulse  to 1-3 ms.

    4.  Eliminate that glitch from the reset signal.

     


    Regards,
    Joel 

  • 0 in reply to Joel Jimenez0
    Prodigy 190 points

    1. Power is more stable now (2 new cap).
    2. Oscilator is 100% stable now.
    3. I tried with different reset pulse 0.1ms, 0.5ms,1ms,1.9ms,2.5ms. Same error.
    4. I can't eliminate glitch totally but now it is 0.5-0.8V.

    Now my chip start to behave diffrently. It doesn't go in suspended mode but "works" as a active (still get crystal and LOW on suspended). No matter of reset state, pulse and duration.
    To be honest I don't know what's still wrong, maybe I will try to replace my TUSB with another one.

    PS. Really glad to know that there is someone like Joel who do his best to help others. Thanks :)

  • 0
    Prodigy 50 points
    Hello Pawel,
    Conventional USB plug has following pinout: VCC, DM, DP, GND. Check twice that DP and DM in JP1 assigned correctly.