TUSB2077A No data?

Jim Papay

Intellectual 330 points

Other Parts Discussed in Thread: TUSB2077A

Hello,

I am Implementing a TUSB2077A and am not getting any data coming across.

First of all let me say:

The #BUSPWR is set to 3.3 v

The P4 Type A plug has no voltage wired to it.

The P5 Type A plug does have voltage wired to it. (With nothing plugged in, I read 0.22 volts on the Out1 of the power distribution switch).

The un-used ports, #OVRCUR5 is floating,

DP5 is floating,

DM5 is floating.

and same for Port 6 and Port 7.

Is there any-thing here that seems would be causing an issue?

Any troubleshooting suggestions?

Sincerely,

Jim

over 9 years ago

0 Joel Jimenez0 over 9 years ago

TI__Mastermind 18655 points

Hello Jim,

The DP and DM signals of the unused port should be tied to ground with 15K resistors like the pull-downs used on the active ports.

The OVRCUR/ input of the unused port can be left tied to the other OVRCUR/ inputs if the hub is configured as GANGED.

Here is our TUSB2077A reference design:

TUSB2036 and TUSB2077A EVM User's Guide.pdf

Regards

0 Jim Papay over 9 years ago in reply to Joel Jimenez0

Intellectual 330 points

Thank-you Joel, I will certainly do that.

I also want to check with you on the mode and crystal set up we have.
Mode pin is set to Gnd.

#extmem is set to 3.3 v
xtal/clk48 is set to one side of our 6.0 MHz crystal
Xtal2 is set to the other side of our 6.0 MHz crystal.

Does this sound like it is correct?

Sincerely,
Jim

0 Joel Jimenez0 over 9 years ago in reply to Jim Papay

TI__Mastermind 18655 points

Jim,

That is correct. Please provide your schematics, I can help to review them.

0 Jim Papay over 9 years ago in reply to Joel Jimenez0

Intellectual 330 points

OK, let me see how I can do it.....

Ok, here is the schematic for the USB Hub.

0 Joel Jimenez0 over 9 years ago in reply to Jim Papay

TI__Mastermind 18655 points

Hello Jim,

The DP and DM signals of the unused port should be tied to ground with 15K resistors like the pull-downs used on the active ports.

The OVRCUR/ input of the unused port can be left tied to the other OVRCUR/ inputs if the hub is configured as GANGED.

The reset signal at power-up must be 1ms to 3ms long after the power supplies reached its 90%.

The link below contains some frequent asked questions:

0 Jim Papay over 9 years ago in reply to Joel Jimenez0

Intellectual 330 points

Thank-you for the help.......it turned out to be resistor values on the DM, DP inputs.

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TUSB2077A No data?