TUSB2046B

We can not read the schematic in the post, can you please attach it rather than embed it.

I cant find a function to attach the file, can you give me your email, so that i can send the File?

To attach files, when you are on the inout screen, you need to click on the "Options" tab right above the post you are replying to:

from there, you should get the option to add a file:

If you would rather, please send to usb@ti.com

Remo,

If I read you schematic correctly, you need to tweak your reset circuitry.

From the data sheet pin decription:  "Generally, a reset with a pulse width between 100 μs and 1 ms is recommended after 3.3-V VCC reaches its 90%. Clock signal has to be active during the last 60μs of the reset window." 

Your RC network is 22 ohms and 1uF which is a reset pulse of ~ 22uS, well below the data sheet guidelines.

Oh, stupid mistake, i changed now the value of the resistor to 220 ohms, so i wil have a reset pulse of 220uS, but there is still the same Error.

Is maybe the TUSB2046B broken?

Regards

Remo

Theoretically it will give you 220us, but taking in mind the time for the power rails to become stable and the time for the clock source...the 220 ohm will be still low.

I recommend a 2.2KOhm resistor.

Regards.

There is still the same Error with the unknown device...

Regards

Remo

Could you take some scope captures of the Reset signal?

Regards.

I took a capture of the Vcc (yellow) and the Reset (green) Signal.

The Reset Signal reaches 90% of Vcc after 2.4ms.

I can't measure a clk on the pins XTAIL1 and XTAIL2, is the clock set up after the initializing?

Regards

Remo

Hello Remo,

You have to "wait" until Vcc reaches it's 90% before start counting the Reset pulse duration. Also, the clock signal must be valid a minimum of 60us before ~RST is deasserted.

The below image shows an example of a 1ms long reset pulse.

Regards.

Hy,

So is it possible to realize the reset pulse with a RC circuit as i have it in my schematics (2.2k Ohms and 1uF)?

I cant find the Value of the Hysteresis from the Reset input?

Regards 

Remo

Yes, it is possible.

The hysteresis value is in the Electrical Characteristics Table, page 6 of datasheet parameter Vhys.

Hos is your clock signal? You can also increase your reset pulse with a 10KOhm.

Regards.