Tiny Raspberry Pi CM4 carrier board with full 40-pin GPIO header
To make the experience fit your profile, pick a username and tell us what interests you.
We found and based on your interests.
PicoBerry_v1.0_project_(CERN_OHL_v1.2_license).zipx-zip-compressed - 4.22 MB - 10/24/2022 at 01:26 |
|
|
PicoBerry_V1.0_Schematic_2022-01-22.pdfPicoBerry - full schematic fileAdobe Portable Document Format - 573.50 kB - 01/12/2022 at 09:05 |
|
|
Project published as Open Source Hardware (OSHW) under CERN OHL v1.2 (Open Hardware Licence).
Source files:
https://github.com/mfolejewski/PicoBerry
Here you can find full PDF schematic:
https://cdn.hackaday.io/files/1827477818647648/PicoBerry_V1.0_Schematic_2022-01-22.pdf
It's time to solder a few boards (missing components - colored pin header + USB-C connector)...
Done! Let's test these boards...
OK, #PicoBerry board is working!
Smallest CM4 carrier board with full 40-pin GPIO header port.
Sorry about the ugly video quality.
https://twitter.com/Mirek34416541/status/1463599187786874887
PicoBerry REV1 boards just arrived!
This time I reduced the PCB pad size for the Hirose connectors to improve soldering and component placement.
...against component floating during reflow soldering.
It should be better now.
Create an account to leave a comment. Already have an account? Log In.
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.
Become a member to follow this project and never miss any updates
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.