I have finished schematics, footprints, 3D models and placed the components and this starts to look good. The pictures below are exported directly from KiCAD. The Top layer contains the Ethernet module, MCU, crystals, leds and SWD. Only the 16Mhz crystal and some caps are under the Ethernet module. The bottom contains a USB-C connector,…
I decided to add place for bothy CAN-FD and RS485 as IPC on the module. The design seen from left is CAN at top, RS485 on bottom – switching the module to right we get the oposite. I have the extra space to do it and it allows me to build modules using UART’s only.…
This ends up as a prototype anyway because I lack components to optimize for production. I am using 4 layers this time because I want better isolation between signals. I can mosly route on a single layer, but I had some bad experience with signal integrity on 2 layers. This is the first time I…
KiCAD 6.0.8 is great. Many new improvements. But, also some issues as links to footprints and 3D images are broken. I opened XPortHub2 because I neeeded reference to a coil and found that the RJ45 is missing on the 3D View – easy to fix, but I have seen a few of these. You also…
As I can’t get hold of the components I want and this becomes a prototype that will change I can as well start using both sides of the board. The SOP8 CAN tranceiver get a bit squeezed on the top layer so I can put it at bottom – in which case I can add…
TI have made an excellent series of CAN-FD Tranceivers in SO23-8 format. All the rest is SOP8 and you can compare the two footprints below. The bugger is that I can get SOP8 versions, but I can not get any of the SO23-8 versions. So for now I have to accept added space here as…
The nice thing about KiCAD is that you find free 3D models for almost every package. Imported a Step file from GrabCAD, made my own footprint and voila. It is a bit space between the PCB’s as the header is not showing, but it gives a good impression of the result. If I want to…
The two first modules I will create is Ethernet and Serial (RS485 & RS232). I have several paths forward to create this, but the most obvious is to create two modules that can go back to back. To connect these two I use a small PCB connecting CAN on J2 – the four pins are…
My KiCAD skills are coming back – just a quick check on the Ethernet module. I reduced MCU to LQFP48 and used a W5500 module through headers. I moved drill holes to the corner. The J45 in the middle is just for show. This is a 25mm x 45mm module and I will have plenty…
Illustrating a possible PCB bus board 90mm x 150mm. I have also played around with alternative sizes, but I like the small 25mm x 45mm and the scalability I got here. The drawback is cost as each module will need a 12.- USD MCU at core.