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FX3 8b/10b decoder errors | Cypress Semiconductor

FX3 8b/10b decoder errors

Summary: 1 Reply, Latest post by Madhu Sudhan on 19 May 2016 01:43 PM PDT
Verified Answers: 0
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hamidk_1515226's picture
2 posts


I am designing a USB device based on CYUSB3011-BZXC. Besides transferring data through a bulk endpoint, device also reports low-level errors occurring on the bus. This is done by calling CyU3PUsbGetErrorCounts and also reading LNK_ERROR_STATUS and LNK_PHY_ERROR_STATUS registers to see what type of errors occurred. My problem is that the device always reports some 8b/10b encoding errors (4~7 errors out of 32KBytes of data).

Is there any special reason that these errors are happening?

how these errors are resolved? 

Thank you,



mady's picture
Cypress Employee
955 posts


There is a possibility of noise when you interface an external chip with FX which results in PHY/Link Errors on USB. 

This issue will not occur if all our schematics and layout guidelines have been followed in your board. If this was the case, some ways to minimise the effect of PHY / Link Errors are:

Either re-work the board layout. Get it reviewed by Cypress Tech Support.


(i) Reduce the VIO power domain voltage levels

(ii) Use Clock instead of crystal

(iii) Change the voltage Swing using the SetTxSwing API (Enter Tx swing values by trial and error and find out which one has least effect of noise). Refer to API guide on how to use this API


- Madhu Sudhan

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