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TUSB212: DC Boost for cable

Shu-Cheng LIN
Guru 11785 points
Part Number: TUSB212
Other Parts Discussed in Thread: TUSB215, TUSB211

Hi Sirs,

Sorry to bother you.

Our question is when we load mp3 from USB Flash Drive, there will delay 10s then start to play music.

The default is mid DC Boost. The long cable will happened but short cable didn't.

But if set to high DC Boost, both cable will happen lag phenomenon.
When we set to low DC Boost, both cable are passed.

Actually we have test eye pattern on mid DC Boost setting, it's passed.

So we would like to know why mid DC Boost will meet lag phenomenon even the  eye pattern passed?

Thanks!!

  • 0
    TI__Mastermind 19720 points
    I have not seen this happen before. Is the TUSB212 in the host or the cable or the device? how long are there cables? What EQ settings are you using? what is the HOST? So the lag only happens on the long cable with mid DC boost and both the short and long cables on High DC boost?
  • 0 in reply to Michael.Walker
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply, please refer update red word as below

    Is the TUSB212 in the host or the cable or the device?

    In the host.

    how long are there cables?

    140cm

    30cm

    What EQ settings are you using?

    what is the HOST?

    Renesas R-CAR M2-W

    So the lag only happens on the long cable with mid DC boost and both the short and long cables on High DC boost?

    Yes!!

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 19720 points
    Could you change the EQ resistor to about 1.7K and then try both cables at MID DC boost and see if there is still lag then?
  • 0 in reply to Michael.Walker
    Guru 11785 points

    HI Sirs,

    Thanks for your reply

    EQ resistor to about 1.7K try both cables at MID DC boost, still lag 10s.

    Only low DC Boost are OK.

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 19720 points
    Can you give better details about this lag? how are you timing this lag? is it lag when loading files from the USB flash drive? Is there a lag when interacting with the file management system? is there only lag when playing music from the flash drive? Have you tried other flash drives or USB devices such as mouses or keyboards and seen this symptom?
  • 0 in reply to Michael.Walker
    Guru 11785 points

    Hi Sirs,

    Please refer red word

     

    How are you timing this lag?

    Please refer video, link as below

    https://drive.google.com/open?id=1RLhRHSUwdryqCUkBtJXvlwuVIj3y6P4v

     

    Is it lag when loading files from the USB flash drive?

    Yes

    Is there a lag when interacting with the file management system?

    Yes

    Is there only lag when playing music from the flash drive?

    60 mV mid DC Boost

    long cable --> 12Mbps  USB 1.1  
    The speed will down to USB 1.1, To play music and movie will lag

     

    Have you tried other flash drives or USB devices such as mouses or keyboards and seen this symptom?

    For now, we only found one devices got this problem. 

    The device detail  please refer as below

    Fullscreen USB device info.txt Download 
    SP�s�o U05 8G
Description: [E:]USB Mass Storage Device(USB DISK 2.0)
Device Type:�@�@Mass Storage Device

Protocal Version: USB 2.00
Current Speed: High Speed
Max Current: 200mA

USB Device ID: VID = 13FE PID = 4200
Serial Number: 0701768B2E8F5282

Device Name: USB DISK 2.0
Device Revision: 0100

Product Model: USB DISK 2.0
Product Revision: PMAP

Controller Vendor: Phison
Controller Part-Number: PS2251-68(PS2268) - F/W 01.08.30 [2017-03-30]
Flash ID code: 983A9493 - Toshiba [MLC]

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 19720 points
    What seems to be happening is that there is data corruption caused by to high of DC boost setting. I recommend that you just keep the DC boost at the lowest setting. Does it pass eye diagram compliance with DC boost in the lowest setting?
  • 0 in reply to Michael.Walker
    TI__Expert 4795 points

    Hi Michael,

    Here is the current test result. 

    1. AC Boost= Level2 : Eye diagram compliance is pass, even if we set the lowest DC boost. But USB pen drive was still lag. 

    2. AC Boost=Level 0 : USB pen drive work normally. But Iphone only got 12Mbps data rate. 

    3. We tried to pull RST of TUSB212 low. Then we found that both USB pen drive and Iphone work normally.

    But eye diagram compliance is failed.

    And if we put one TUSB215 EVM in the middle, we can reproduce the same issue again.

    So my questions are:

    1. Is it possible that TUSB212 DC boost broke the USB handshake between the host and Iphone? So that it only get USB1.x spec data rate?

    2. Are we able to disable DC boost? We are trying to get some TUSB211 sample for test now.

    3. Do you have any other suggestion?

    Please advice.

  • 0 in reply to Jim CHEN
    TI__Mastermind 19720 points
    Oh, is this a Carplay application?
  • 0 in reply to Michael.Walker
    TI__Expert 4795 points
    It's a similar thing, but it's not exactly the same as Carplay. It's a car machine application.
    Have you met this issue before?
  • 0 in reply to Jim CHEN
    TI__Prodigy 160 points

    1. Is it possible that TUSB212 DC boost broke the USB handshake between the host and Iphone? So that it only get USB1.x spec data rate?

    No, our redriver wouldn't broke the procedure of negotiation. But higher DC boost would leads to High Speed disconnection. I consider the dc level is very close to  disconnect threshold, so sometimes the handshake would fail, and host reset, then reconnect... 

    2. Are we able to disable DC boost? We are trying to get some TUSB211 sample for test now.

    Yes, You could disable DC boost if you could use I2C access the register of 212.

    3. Do you have any other suggestion?

    EQ and DC boost would help you pass compliance test, but we don't think higher DC& EQ are good for you. So I advice that you could choose the smallest value from all settings that can be passed the eye diagram.

  • 0 in reply to Jim CHEN
    TI__Expert 3655 points

    Solution is DC boost low and eq 1.