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PSoC™ 5, 3 & 1 Forum Discussions

user_294846
Level 3
Level 3
First like received

Hi,

I want to add some logic wrapped to the CAN component for FD tolerant operation as mentioned in https://can-newsletter.org/uploads/media/raw/35a48f1d88ddf2a198638c0a5be51761.pdf .

The design is mostly done,

Tx output switching is OK with a tristate output pin (thanks to the transceiver pull-up)

but I have a problem with rx input switching. The error message is;

Error: mpr.M0074: The RX port on CAN block "\CAN:CanIP\" must be directly connected to an IO pin. (App=cydsfit)

psoc_creator_DIKwGGQtWA.png

It's working with the following way, but it wastes a pin;

psoc_creator_0d0NbhfoD0.png

Do you have any idea to do it without any wasted pin? Is there any way to remove the rx pin constraint of CAN component?

( same issue : CAN-BUS: 2 controllers in 1 chip => 1 transceiver, how to do it? )

Thanks, Regards.

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1 Solution
user_294846
Level 3
Level 3
First like received

Hi,

I have finished the design. It works in my case and everything looks like OK. Further improvements may be done but I will not be able to spend more time. Further tests should be done also. I'm uploading the design here as a workspace. Anyone can use it for any purpose with their own responsibility.

psoc_creator_VP20rCVd9f.png

Any test result, bug report/fix, improvement is welcome.

Maybe Cypress guys add this to the CAN component as a checkbox like "Enable FD Tolerant Operation" with cleaner method.

If CAN IP have other IOs that we can't see, further improvements could be done. For example;

If it have bus idle, bit clock or stuff bit signals accesssible then these are reusable and some resurces can be saved.

And it would be good if Cypress adds to a "non - pin constrained" version for the CAN component or primitive.

Regards.

View solution in original post

6 Replies
Len_CONSULTRON
Level 9
Level 9
500 solutions authored 1000 replies posted 750 replies posted

Hi,

This is a design limitation imposed by the author of the CAN component.

Submit your idea for making the CAN component CAN-FD tolerant to Cypress.  They may be interested.

A more complicated way is to import the CAN component into your design.

pastedImage_0.png

Next modify the code that requires it to be directly connected to a pin.

Or ...

Modify the CAN_v3_0.cysch file to include the "AND" gate and a new input "FD_frame".  This should get around the "must be attached to a pin" requirement.

pastedImage_1.png

Just some thoughts.

Len

Len
"Engineering is an Art. The Art of Compromise."
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Hi Len,

Thanks for your reply.

Adding "AND" in the component symbol didn't solve the problem.

The restriction comes from inside of the "cy_psoc3_can_v1_0" primitive.

Directly instantiating the primitive in the top schematic also gives the same result.

psoc_creator_kBIJHnMtVP.png

I couldn't find any related parameter in the primitive symbol/pin properties.

Thanks, Regards.

0 Likes

Thanks for the feedback.

I imported the cy_psoc3_can.  There appears to be no control of this component primitive for the user.  Sorry I couldn't be of more help.

Len

Len
"Engineering is an Art. The Art of Compromise."
0 Likes
user_294846
Level 3
Level 3
First like received

Hi,

I have finished the design. It works in my case and everything looks like OK. Further improvements may be done but I will not be able to spend more time. Further tests should be done also. I'm uploading the design here as a workspace. Anyone can use it for any purpose with their own responsibility.

psoc_creator_VP20rCVd9f.png

Any test result, bug report/fix, improvement is welcome.

Maybe Cypress guys add this to the CAN component as a checkbox like "Enable FD Tolerant Operation" with cleaner method.

If CAN IP have other IOs that we can't see, further improvements could be done. For example;

If it have bus idle, bit clock or stuff bit signals accesssible then these are reusable and some resurces can be saved.

And it would be good if Cypress adds to a "non - pin constrained" version for the CAN component or primitive.

Regards.

I appreciate your hard work and for sharing your insights on how the CAN component might be updated for CAN-FD.

Len

Len
"Engineering is an Art. The Art of Compromise."
0 Likes

Hi user_294846​,

We really appreciate your commitment to post your solution to our community.

Since PSoC 5 is a old device, we might not be able to provide  upgrades (hardware/ software) in the near future.

We highly recommend you to use our latest PSoC 6 device that supports CAN- FD in hardware. Please feel free to evaluate our PSoC 6 device for your application.

https://www.cypress.com/file/151476/download

Thanks for your valuable contribution to our community.

Regards,

Bragadeesh

Regards,
Bragadeesh
0 Likes