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USB Superspeed Peripherals

KeWa_2323766
New Contributor II

FX3 GPIO46 is used as PWM output.  I refer to excel document attached to the thread

https://community.cypress.com/t5/USB-Superspeed-Peripherals/IO-Drive-Strength-configuration-for-P-po...

But in this document, with same IO VDD, IOH, Drive strength, different Forced VDD will result in different drive current for GPIO46. 

1.  What does " forced VDD" mean in the excel file?

2.  What is default GPIO drive strength when no CyU3PSetGpioDriveStrength( ) called to set drive strength, 1/4,2/4,3/4 or 1?

3. Is there difference between simple GPIO and complex GPIO in term of drive strength?

Thank you.

Kelly

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1 Solution
Rashi_Vatsa
Moderator
Moderator

Hello Kelly,

Apologies for the confusion

Please check the table 9  in the latest FX3 datasheet https://www.cypress.com/file/140296/download

As per the FX3 TRM, the default drive strength will be Half strength as the default value of GCTL_DS register  is 2

 0 Quarter strength
1 Three quarter strength
2 Half strength
3 Full strength

Regards,
Rashi

View solution in original post

4 Replies
Rashi_Vatsa
Moderator
Moderator

Hello Kelly,

Please find my comment below

You can refer to table 9 of the FX3 datasheet for the current values for different drive levels

2.  What is default GPIO drive strength when no CyU3PSetGpioDriveStrength( ) called to set drive strength, 1/4,2/4,3/4 or 1?

>> Please refer to section 10.4.4 of  FX3 TRM. It mentions about the GCTL_DS register. You can also refer to this thread Solved: what is the default state of CyU3PDriveStrengthSta... - Cypress Developer Community

I will  get back to you after confirming for the other questions

Regards,
Rashi
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KeWa_2323766
New Contributor II

Rashi,

Thanks.

I am not able to find GPIO current values in data sheet Table 9 . Table 9 is for GPIF ii timing.  Please see the screen shot below.

KeWa_2323766_0-1613961079324.png

If you help me  explain the forced VDD, it would help me a lot .

Regards,

Kelly

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Rashi_Vatsa
Moderator
Moderator

Hello,

Please check the table 9  in the latest FX3 datasheet https://www.cypress.com/file/140296/download

The drive strength of all the GPIO by default will be Three-Quarters

Regards,
Rashi
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Rashi_Vatsa
Moderator
Moderator

Hello Kelly,

Apologies for the confusion

Please check the table 9  in the latest FX3 datasheet https://www.cypress.com/file/140296/download

As per the FX3 TRM, the default drive strength will be Half strength as the default value of GCTL_DS register  is 2

 0 Quarter strength
1 Three quarter strength
2 Half strength
3 Full strength

Regards,
Rashi

View solution in original post