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USB Superspeed Peripherals

SeungM_41
Employee

Hello

My customer has some question about drive strength for storage port (S0) with SD3 (CYUSB3025-BZXI).
Could you give me your comment for the question?

 

Question#1.
What is default drive strength for S0 port? (Half strength? or Three quarter strength?)

Question#2.
Can be the drive strength changed by USB host during system operating?

Question#3.
Can you please let us know how to change the IO drive strength in firmware?


Regards,
Jake

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Rashi_Vatsa
Moderator
Moderator

Hello Jake,

1) What does it mean default value 2 in S0DS[1:0]? (Half strength? or Three quarter strength?) 

>> Apologies for the confusion. You can follow the details mentioned latest FX3 TRM (rev *F) https://www.cypress.com/file/134661/download. The default IO Drive strength will be 2 - Half strength

2) As per FX3 TRM, the S-port I/O drive strength is programmable similar to any other I/O pin as discussed in 4.1.2 I/O Drive Strength on page 53.

what is file located for IO drive strength configuration? 

>> To change the drive strength of the S port you need to write to the register GCTL_DS. The project does not contain the API for doing that. You can use CyU3PWriteDeviceRegisters/CyU3PReadDeviceRegisters APIs  to write/read to the register. The register can be written with different drive strength in firmware

You can refer to the source of this CyU3PSetGpioDriveStrength API to get more details on writing to the register.  Similarly, you can set particular bits of the GCTL_DS register according to your application

Please let me know if you have any queries on this

Regards,
Rashi

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