Platform forum


besim321123 , 03-16-2019, 10:54 AM
Now as you know STM present their product(STM32MP1) which can run Linux. So I plan to design SOM which is included STM32MP1 then baseboard for SOM. I downloaded all documents of STM32MP1 but I have some kind of problem. I decided to ask these question and I would like to get advice from you for this project.

As I said you , STM published all document which are datasheet, Altium document etc. I have examined these document and I saw that ST made the board 4 layer and length matching is not good for some addres. Tollerance has to be at least 25 mil right ? Maybe there's something that I don't know. Also I can not see anything about DDR routing guide in datasheet. So I was suprised. I think it has to be at least 6 layer. if I make it 4 layer. may it be problem ? I wanted to ask your idea. I am not sure how many layer should I use.

What are your recommendations about this project to successfully complete? what should I pay attention?

Your advices are important for me!!

besim321123 , 03-19-2019, 06:25 AM
i am wondering why anybody dont help me
mairomaster , 03-20-2019, 02:55 AM
Routed length includes the tracks to the termination resistors. You need to setup xSignals between the processor and ram pads, so you can get a proper measurement of the signal length.
robertferanec , 03-21-2019, 06:45 AM
@mairomaster is right. You can not be looking at PCB Panel -> Nets -> Routed length (this will show you the total routed length - you need to see only the length between the chips). You need to be looking into PCB Panel -> xSignals and you need to create xSignals so you can see only the length between chips (you can use also xSignal Wizard). Maybe this video can help: https://www.fedevel.com/welldoneblog...useful-things/
besim321123 , 03-21-2019, 06:59 AM
Thanks for your answers! What do you think about layer ? What are the disadvantages of making 4 layer? How many layer should i do ? What are your recommendations ?
robertferanec , 03-21-2019, 07:20 AM
I have not seen the reference board from STM - I am not sure how they do the reference planes. From the picture it looks like only 1 memory chip is connected to the CPU, it may be possible to use 4 layers - if pinout of the CPU is correct.
Use our interactive Discord forum to reply or ask new questions.
Discord invite
Discord forum link (after invitation)

Didn't find what you were looking for?