CYUSB3035-BZXI USB detection fail

[shva_4703666]

Hi there,

I am using CYUSB3035-BZXI in USB mode. The USB detection is failing for few boards. Can you please let me know what might be the causes of USB detection failure.? PFA the pic of the USB connection details. 

[JayakrishnaT_76]

Hello,

1. As per my understanding, you are making use of a Type C plug for connecting the device to the host PC. Please let me know if my understanding is completely correct or not. Please correct me if my understanding is wrong.

2. Please share the snapshot of schematics showing how the USB lines are routed between the connector and FX3S so that we can understand more about this problem

[shva_4703666]

Hi Jayakrishna,

Sorry for the late reply.

Yes, I am using the Type-C connector. 

PFA the cropped schematic. Please let me know if this is sufficient. Adding to that, can you please verify on the SGND to DGND  connection. 

[JayakrishnaT_76]

Hello,

From the snapshot of the schematics shared, I find that the decoupling capacitors are not connected as that mentioned in Table 3 of AN70707. The link to the same is given below:

https://www.cypress.com/file/139936/download

I also found that ferrite beads are not connected on AVDD, U3TXVDD, U3RXVDD, and CVDD. Please refer to Figure 1 - EZ-USB FX3 Power Domains Diagram of AN70707 to understand how these connections are to be made. The same is applicable for FX3S also.

Please check this and let us know your comments on the same.

Also, please provide the following information for debugging the issue further:

1. From the schematics, it seems that the device is self powered. Please confirm if my understanding is correct or not. 

2. What percentage of the boards are not enumerating? Does the failing boards enumerate if the reset button is pressed after connecting the device to host?

3. Can you please check for shorts in the USB connector?

[shva_4703666]

Hi,

The Ferrite beads and decoupling capacitors are there in the schematics. I have checked the connector for short, and have replaced the connector as well. 

I am getting such issue on 4 boards out of 12. 

I am powering from the USB port from laptop. I've provided the power on reset option. The issue is observed as soon as I connect the board. I get the voltage on the board, but detection is not happening.

Please let me know if I need to check anything further. 

[JayakrishnaT_76]

Hello,

I still did not find the ferrite beads and decoupling capacitors as mentioned before in the snapshot of the schematics shared in your last response. For example, I did not find the ferrite beads near A2 and A7 of FX3S device. Please let me know if they are placed at a different place within the schematics.

Also, as per my understanding, 4 out of 12 boards does not enumerate as FX3 Bootloader device. Please correct me if my understanding is not correct. If this is the case, then please check the Hardware section of the following KBA:

https://community.cypress.com/t5/Knowledge-Base-Articles/Trouble-Shooting-Guide-for-the-FX3-FX3S-CX3...

Also, please let me know if  the failing boards enumerate correctly upon pressing the reset button.

[shva_4703666]

Hi, 

Yes, the Ferrite beads are at the another page. PFA. The other boards are working with the same connection. Your understanding is correct. I have replaced the Cypress device as well. 

As I told, I have provided the power on reset using RCD circuit, I do not have another provision to reset from hardware.

Sure I will check the link. 

Thanks 

[JayakrishnaT_76]

Hello,

Please let us know if the issue is fixed after referring to the KBA mentioned in my previous response.

[shva_4703666]

Hi Jayakrishna,

I could not debug further. I have checked the hardware part & firmware is not changed. 

[JayakrishnaT_76]

Hello,

As per my understanding, the device is not coming up as Bootloader device in the control center even after the design follows all the recommendations provided in Hardware section of the following KBA:

https://community.cypress.com/t5/Knowledge-Base-Articles/Trouble-Shooting-Guide-for-the-FX3-FX3S-CX3...

If this is correct, then considering the fact that 8 out of 12 PCBs enumerated correctly on the same PC, I suspect that any of the components on the failing PCBs may be defective. Can you please check this and let us know the results?

[JayakrishnaT_76]

Hello,

Please let me know if you could find any problems in the components used for the failing PCBs. Please let me know if the issue is resolved or not.