Oh yes of course. SMI is just a secondary memory interface exposed on the RPI in ALT5 GPIO2-27

If you expose those default RPI GPIO2 to GPIO27 then you implicitly expose also the SMI. And that interface is great because it is a high-speed bus for bulk transfers.

see my project:

https://github.com/cariboulabs/cariboulite

did not write a full documentation on that yet but, its there...

So you got an amazing idea here with PicoBerry that exposes ComputeModule as if it was a RPI4 and I'm surprised Raspbery Pi didn't do it yet :)

Anyway, by taking into account the signal integrity in your board (proper grounding) you can proof it for these high speed applications.

I have not heard about this interface so far. Thanks!

I don't have the resources now to test SMI mode. Anyway sounds interested (high-speed interface).

Maybe PicoBerry requires to length match GPIO traces and correct impedance tracks (50Ohm?) and add extra 2 reference ground planes. This can be a future plan (I'm too busy up to the end of this year).

Thanks for your info!

Regarding the board - did you consider high speed interfaces like the SMI? in terms of impedance control, etc.?

SMI interface? Hmm... All the high-speed interfaces are connected to the second Hirose connector.

This is a simple carrier board with only exposed GPIO lines.

Can you explain about SMI?

This project is just amazing. I want to have one of those boards for CaribouLite over the RPI-CM... any way to get it?

Edit: Ok now I see its a two layer board. I would consider turning it into a 4 layer stack with two gnd planes in the middle. If you need help with it, just tell me. you can also route the power partial planes there so it will be much simpler. Then you get a really good power / signal integrity for those high speed lines

I use SMI, some other will use DPI (display parallel lines) to connect an external LCD. Both of which require a good grounding.

Anyway, if you need help, I'm here. David

The project can be modified to add extra reference planes for signal lines (GPIOs) and for power rails.

If you are interested to order 1pcs in the current version just let me know (DM).

There is no high-speed signals, they are located on the second Hirose connector.