Hi Alin, That is basically the idea.
We will have a SODIMM in the baseboard that will accept different CPU/MCU modules. The baseboard will have some basic components (most common in many NuttX boards and low cost) and connectors to let people to test different devices. We are not planning to create a stackable "skyscrap" board, just the CPU/MCU module in the top, and the baseboard in the bottom with connector options to add other devices. Since we are planning to include the Ethernet in the CPU/MCU Module (because many MCUs don't have Ethernet and adding Ethernet to the baseboard means we are testing a single PHY all the time), maybe we could consider adding the Ethernet as a connector. We could adopt the same Ethernet connector used on Viewtool STM32107 (Ficus STM32F107 Development Board) that NuttX already supports, the advantage of this connector is because it is a common 0.1" pin header. These are ideas that we could explore, but I suggest we don't make it too complicated, otherwise we will not meet our goal (have a simple board to test different MCUs and make automated tests easier to do). BR, Alan On Tue, Sep 9, 2025 at 5:05 AM Alin Jerpelea <jerpe...@gmail.com> wrote: > Sorry for my slow replay > > I propose that we create a bare carrier board with connectors for different > SOC modules and different peripherals/storage > > This approach would maximize the combinations that can be tested using a > single base board > > I would propose that we create the boards stackable with distributed power > and data lines to facilitate the testing farm application > > Best regards > Alin > > > On Mon, Sep 8, 2025 at 3:01 PM Alan C. Assis <acas...@gmail.com> wrote: > > > Hi Tomek, > > > > Thank you for attending the event. > > > > We will mix the two possibilities: we will have basic and most chips (and > > low cost) soldered on the board and we will have connectors available to > > people to test other modules. > > > > This way the board will be useful for testing purposes (to quickly and > > eventually automatically tests) to detect issues and also for pragmatic > > applications. > > > > BR, > > > > Alan > > > > > > On Mon, Sep 8, 2025 at 9:49 AM Tomek CEDRO <to...@cedro.info> wrote: > > > > > Thank you Alan for leading this great initiative and everyone > > > paritcipating :-) > > > > > > Sorry I was on the trip yesterday, could only for a moment on a train > > > station, then I lost connectivity :-( > > > > > > This DIMM DDR2 SO-DIMM connector is nice for the CPU board aka > > > "compute module" using similar connectors :-) The only problem I see > > > here is radio antenna connectivity this is always pain in the butt :-P > > > I can see Sebastien commented about 1mm thickness of the PCB but this > > > is not a problem this is standard thickness easy to manufature at home > > > too :-) I use often 0.5mm 1.0m 1.5mm :-) Factories now can make 10 > > > layers, flexible, translucent, all sorts of magic :-) > > > > > > Then the mainboard can be easily extended / replaced / upgraded for > > > what is needed. For a long time (since ~1997) I am using this modular > > > approach for various initial prototypes, where each chip has its own > > > board and connectors that can be then connected with other boards > > > breadboards etc. Its very popular nowadays :-) > > > > > > One question - do we want to solder chips on the mainboard or just > > > provide conenctors for the chip-board? Having everything as module > > > would make mainboard cheaper to manufacture, faster to solder, also > > > chip cpecific boards will be faster and cheaper to manufacture, and > > > most of all we would easily reconfigure / upgrade mainboard > > > peripherals when needed even without soldering - we can then replace > > > just one small board when needed. One disadvatage is signal integrity > > > for high speed bus.. but it would be better than loose wires anyways > > > :-) > > > > > > It would be nice if all boards are designed in a way they can be > > > manufactured at home :-) I have pretty good LPKF cnc for pcb so I can > > > test two layer/side designs. But also pcb making with laser printer > > > toner transfer should be possible. Thus some DRC rules would be nice > > > to define such as minimum track width 0.5mm etc :-) Probably for CPU > > > board these will be smaller due to quite dense connector? > > > > > > We could then produce gerber / drill / cut files for the boards, pack > > > them up on a single layout, and send to factory to get a bundle like > > > 5x for low cost and then solder things up at home? Maybe ordering > > > already soldered boards can be cheap too. It would be good to provide > > > cos simulation from various places when things are ready :-) > > > > > > Thanks again! :-) > > > Tomek > > > > > > > > > > > > On Sun, Sep 7, 2025 at 10:06 PM Alan C. Assis <acas...@gmail.com> > wrote: > > > > > > > > Hi Everyone, > > > > > > > > Thank all participants of the meeting about the NuttX Standard Board. > > > > > > > > For those who were unable to attend, the video is available on > YouTube: > > > > https://www.youtube.com/watch?v=keZAZ8GiYzI > > > > > > > > Just a summary of our meeting today: > > > > > > > > - It was defined that we should use the DIMM DDR2 SO-DIMM. > > > > Pros: It has 200 positions (pins); Low Cost; Easy to solder manually; > > The > > > > CPU/MCU Modules don't require a connector. > > > > Cons: the CPU/MCU module needs to use ENIG ( > > > > https://en.wikipedia.org/wiki/Electroless_nickel_immersion_gold) > that > > > is a > > > > little bit more expensive than simple PCBs > > > > > > > > - In order to simplify the base board routing and avoid complexity > some > > > > high speed interfaces (LCD, Ethernet) will be in the CPU/MCU Module. > > (but > > > > the signals will be available in the connector (TBD)) > > > > Pros: Simplify the board design; Avoid rigid rule of have only a > single > > > > Ethernet's PHY or LCD module tested all the time; > > > > Cons: The CPU/MCU Module will end-up becoming more expensive because > > > these > > > > extra components > > > > > > > > - The Mainboard/Baseboard will have the most common > sensors/peripheral > > > > soldereds in the board and an expansion connectors (i.e. MicroBUS, > > P-MOD, > > > > MicroMOD, etc) to let users/developers test other devices. > > > > Pros: Reduce final cost; Brings more flexibility > > > > Cons: Increase the board size to support these expansion connectors. > > > > > > > > We should have a new meeting next week (Sunday) to decide which > devices > > > we > > > > will include in the board, if you have suggestions to improve our > > board, > > > > please participate. > > > > > > > > BR, > > > > > > > > Alan > > > > > > > > On Sun, Sep 7, 2025 at 9:14 AM Alan C. Assis <acas...@gmail.com> > > wrote: > > > > > > > > > Hi Everyone, > > > > > > > > > > For those who will participate in the design phase, please join in > > the > > > > > Jitsi, we will start in 45min: > > > > > > > > > > https://meet.jit.si/Developing_NuttX_Standard_Board > > > > > > > > > > BR, > > > > > > > > > > Alan > > > > > > > > > > On Sat, Sep 6, 2025 at 11:57 AM Alan C. Assis <acas...@gmail.com> > > > wrote: > > > > > > > > > >> Hi Everyone, > > > > >> > > > > >> We will have tomorrow morning (afternoon/evening for merians A to > M) > > > our > > > > >> first meeting about the NuttX Standard Board: > > > > >> > > > > >> https://www.youtube.com/live/keZAZ8GiYzI > > > > >> > > > > >> New to this subject? Ref: > > > > >> > > > > > > https://github.com/NuttX/nuttx_hardware/blob/main/Documentation/standard/index.rst > > > > >> > > > > >> Please join us to define which features we need to have in this > > board. > > > > >> > > > > >> BR, > > > > >> > > > > >> Alan > > > > >> > > > > > > > > > > > > > > > > > -- > > > CeDeROM, SQ7MHZ, http://www.tomek.cedro.info > > > > > >
