TUSB8041: can not recognize the USB disk

user4030839

Prodigy 160 points

Part Number: TUSB8041

After power up ,the CPU can recognize the TUSB8041,but can not recognize the USB disk.

Here is my power up timing,figure 1 is 3.3V ande 1.1V,figure 2 is 1.1V and GRSTZT.

Figure 1

Figure 2

Here is the log:

root@localhost:~# lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 0451:80ff Texas Instruments, Inc.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I doubt if there is a problem with the driver?

over 4 years ago

0 Brian Zhou over 4 years ago

TI__Guru*** 127605 points

it could be, can we look at your schematic?

0 Malik Barton57 over 4 years ago

TI__Guru 64326 points

Hi,

Which channel is 1.1V and 3.3V in figure 1?. TUSB8041 should have 1.1V rial be stable before 3.3V rial when using a passive reset (Single 1 uF cap on GRTz).

0 user4030839 over 4 years ago in reply to Brian Zhou

Prodigy 160 points

Here is my schematic:

TUSB8041原理图.pdf

0 user4030839 over 4 years ago in reply to Malik Barton57

Prodigy 160 points

Hi，

Yellow is 3.3V and blue is 1.1V in figure 1,yellow is GRSTz and blue is 1.1V in figure 2。

In the datasheet,timing requirements is

In my design, 3.3V rial is stable before 1.1V rial,and there is an active reset which meet the 3ms power up delay counting from both power supplies being stable to the de-assertion of GRSTz.

So,I want to know why it doesn't work .

0 Malik Barton57 over 4 years ago in reply to user4030839

TI__Guru 64326 points

Hi,

I agree your power up sequence looks good. It seems you have reconfigured your device in SMBUS mode. Please see the quote from the datasheet:

"The TUSB8041 will wait indefinitely for configuration by the SMBus host and will not connect on the upstream port until the SMBUS host indicates configuration is complete by clearing the CFG_ACTIVE bit." - 8.4.3 SMBus Slave Operation in datasheet.

Are you modifying the CFG_ACTIVE bit via SMBUS? If you are not using SMBUS please place TUSB8041 in I2C mode by pulling pin 39 high (pulled low in you schematic). This should allow TUSB8041 to function normally.

0 user4030839 over 4 years ago in reply to Malik Barton57

Prodigy 160 points

I have tried left Pin 39 float,but it still doesn't work .

0 user4030839 over 4 years ago in reply to Malik Barton57

Prodigy 160 points

After power up,if I reset the TUSB8041 manually(short the GRSTzpin and GND for 3s ),the CPU can recognize the USB disk.

If the TUSB8041 is in SMBUS mode,how to explain the reset thing?

0 Malik Barton57 over 4 years ago in reply to user4030839

TI__Guru 64326 points

Hi,

This is strange behavior indeed. Can you confirm that there is a good ground connection on the thermal pad of TUSB8041? Strange behavior like this can show up when there is not a good connection on the thermal pad. You may consider re-flowing the part as well.

If this does not help I believe that USB_Vbus goes high before the USB Host is ready to communicate. This can cause downstream devices to not appear to the OS and can be solved by resetting TUSB8041.

0 user4030839 over 4 years ago in reply to Malik Barton57

Prodigy 160 points

Hi，

I make the USB_VBUS goes high after the USB host is ready ,it can work now.

Thank you so much!

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TUSB8041: can not recognize the USB disk