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About pad scheme of i3c prototype on fpga

lambert_yu
Beginner
901 Views

Hi all,

   I want to build one i3c prototype on fpga, but I find that all pins can only used as one of the push-pull or open-drain, I don't find that one pin can switch drive mode between push-pull and open-drain, anyone can provide me some advice, thanks.

 

Best regards,

Lambert

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5 Replies
NurAiman_M_Intel
Employee
888 Views

Hi,


Thank you for contacting Intel community.


May i know what is the device number for the FPGA?


Thanks.


Regards,

Aiman


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lambert_yu
Beginner
884 Views

Hi airman,

  I have cyclone v, arria v, arria 10, cyclone 10 board, but I don’t find which one can fulfill my need, or can you provide some advice or fpga kind which can resolve my problem, thanks.

   Best Regards,

Lambert 

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ak6dn
Valued Contributor III
873 Views

You'll find in FPGAs the operating characteristics of a pin are not dynamically settable (ie, LVCMOS vs LVTTL vs LVDS, etc), dynamic pullups, bus hold, totem-pole vs open collector. They can be programmed at startup but are hard (but not necessarily impossible) to change dynamically.

A driver enable can enable/disable the driver function, but it is an all or none option.

Simplest is probably to assign two adjacent pins, an open collector driver with enable, and a totem-pole driver with enable. Then chose one to sample input on, and enable one driver or the other as needed.

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Lambert
New Contributor I
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Hi ak6dn
So maybe I can use this method currently, and will such pins appear in new FPGA models in the future?

B.R,
Lambert
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ak6dn
Valued Contributor III
864 Views

So maybe I can use this method currently, and will such pins appear in new FPGA models in the future?

Since I don't work for Intel/Altera, I can't make any comment on this other than 'not likely', in my opinion.

The usage scenario is quite small for this feature, and using two pins vs one is not a big deal in that case.

It is not like you are going to build a controller that needs hundreds of 'I3C' interfaces.

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