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USB superspeed peripherals Forum Discussions

jayesh_joshi
Level 4
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Hi All,

I have been working with CYUSB3065. During board bring up I ran into an issue where the device is not visible in the control center. We have checked all the clock, and voltages and they are as expected. After further debugging we found that USB_IN_P is remaining high when it is connected to a PC. We have removed L2 from the attached image and still, we are getting 3.3V on USB_IN_P. 

 

jayesh_joshi_1-1659359091198.png

 

Please help me understand how this pin can be high. 

FYI in our older revision board, it is low. 

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1 Solution
jayesh_joshi
Level 4
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Level 4

@JayakrishnaT_76 

 

We have found an issue in the assembly. ESD diodes were not connected correctly or were damaged. We are investigating it. But after removing them we are able to detect USB2.0.

 

Thank you for your support.

View solution in original post

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

Please share the following details so that we can debug the issue further:

1. Complete schematics of the board

2. How many boards have you tested and how many of them show this failure? What is the failure rate?

3. When you say that L2 was removed and the voltage was probed on USB_IN_P, I understand that the pin is not connected to the corresponding pin in the receptacle. In this case, did your older board also show HIGH? Or did it show LOW?

4. Can you please let me know if both the older and newer boards made use of the same type of receptacle (type C/B) or are they different?

Best Regards,
Jayakrishna
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jayesh_joshi
Level 4
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Level 4

@JayakrishnaT_76 

Thank you for the response.

1. Please find the controller and receptacle section of the schematic. I can not share the whole schematic as it is proprietary. Let me know if you need to look at more sections.

jayesh_joshi_0-1659415381695.png

 

2. Two boards are showing this type of issue. It is a new batch and the failure rate is 100%.

3. We have not removed L2 on the older board. But with L2, USB_IN_P is showing Low on the older board.

4. We have two older boards. One has Type B and the other has Type C receptable. 

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

Please check if you have followed all the schematics checklists mentioned in the following link:
https://www.infineon.com/dgdl/Infineon-AN70707_EZ-USB_FX3_FX3S_SX3_hardware_design_guidelines_and_sc...

Specifically the clock and reset part of the schematics. 
In addition to this, is it possible to test more boards in the new batch and let me know the failure rate?

Also, please note that without L2, the USB_IN_P connected should obviously show 3.3V. But, with L2 connected, it should show LOW.

Best Regards,
Jayakrishna
jayesh_joshi
Level 4
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Level 4

@JayakrishnaT_76 

So as I understand correctly, USB_IN_P should be High by default, and when it is connected to the 2.0 port on the PC, the PC will drive this PIN to low. Is that correct understanding?

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JayakrishnaT_76
Moderator
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Moderator

Hello,

Yes, your understanding is correct.

Best Regards,
Jayakrishna
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jayesh_joshi
Level 4
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Level 4

@JayakrishnaT_76 

Thank you for confirming that.

Can you please help me understand what could be the reason why PC is unable to pull down this line? I have shared this with our hardware team as well. 

Also, they have confirmed that they have followed all the schematics checklists in the older boards as well as this board.  

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

At this point, we cannot conclude anything. It looks like FX3 is behaving properly by pulling the Dp line HIGH at start. This is the reason why I asked to check on multiple boards. It could be due to a component failure or possible issues in layout or even in manufacturing and assembly.

Can you also try shorting L2 and see if the issue exist with this change too?

Best Regards,
Jayakrishna
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jayesh_joshi
Level 4
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Level 4

@JayakrishnaT_76 

We have shorted L2 and after we are seeing 0.8V. 

We have checked 3 boards and all are behaving are same.

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

This behavior looks proper. So, the issue can be due to L2. Was the same L2 used for previous boards?

Best Regards,
Jayakrishna
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jayesh_joshi
Level 4
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Level 4

I thought it should be 0V because boards that are working (Detected in the control center and are older) it is showing 0V. In newer boards, it is showing 0.8V so I thought 0.8V is not expected. Am I missing something?

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

Please refer to the following link:

https://www.usbmadesimple.co.uk/ums_6.htm

Best Regards,
Jayakrishna
jayesh_joshi
Level 4
10 questions asked 25 sign-ins 10 sign-ins
Level 4

@JayakrishnaT_76 

 

We have found an issue in the assembly. ESD diodes were not connected correctly or were damaged. We are investigating it. But after removing them we are able to detect USB2.0.

 

Thank you for your support.

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JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

We are glad to hear that the issue is resolved!

Best Regards,
Jayakrishna
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