FEDEVEL
Platform forum

MustafaE , 08-27-2019, 07:29 AM

Hi everyone
My question will be more general one. I know how to use altium designer and feel comfortable while designing any pcb. I also know there are lots of things I should learn.
We buy boards with different processors, communication type and memory elements. But my confusion comes from this point. I want to be the one to select the processor and specific memory components that work with the selected processor and output specific data with desired interface. How should I decide on these components? Is there any article, tutorial you can advise? If there are any resource that will boost my knowledge; at least at introduction level I am ready to thank you.
Thanks

Paul van Avesaath , 08-28-2019, 05:15 AM

Hi mustafa,

most of the time it is done through recommendations and reference designs. so if you know your key components (like CPU or FPGA) you look at reference designs and see what they use.. also you have to read datasheets really well to determin what type of memory can be used.. also depending on you project and data throughput you have to look at what interfaces you need. so x8 or x16 or x32 bit configurations. experience comes from just asking manufacturing and people in the field what they would do.. also reading your question it seems you want to go the step towards an system architect.. that is something that you cannot learn in that sense.. that happens because you have made multiple designs and seeying what worked and what did not..

from my own experience i recommend looking at current desings and trying to understand why some components are chosen.. and if you cant figure oout why that is.. ask the person who made it..

before you know it you will have an idea for your self and start from that with making a block schematic on paper to determine the main parts.. like cpu, mem, IO, Power, etc.. and then starting from the beginning by asking yourself questions like: if i use this cpu.. what power do i need.. how much IO do i need and can the cpu supply this.. how much memory does this interface need.. etc etc.. and it will snowball from there.. as soons as you hit a bump in the road and you become stuck .. ask other designers for help.. and thus you learn.. maybe they will say something like.. hmm maybe an FPGA would be better in this case.. and you start all over again..

trust me when i say that if you stay humble there is no engineer that will not help you if they can.. i have worked with many desingers and architects.. they are all geeks at hart and they love being asked for advice..

i hope this helps you in a very small way.. and maybe robert has some good advice other than try and fail over and over again.

robertferanec , 08-28-2019, 06:55 AM

I would like to add to @Paul van Avesaath's answer.

Main problems with memory chips are register settings. There is number of parameters what has to be set correctly in registers based on specific memory chips what you use (especially different timings). So generally we use the same memory chip types from same manufacturer as used in the reference designs. Otherwise some tweaking and heavy testing may be required to be sure that the board is working perfectly reliably.

Main problem about the other chips is software. Once you go to OS running boards, you need to be sure you have drivers for everything what you use - and it is not easy to write drivers (sometimes impossible). Also, occasionally happen, that some chips do not work together even if they should. So again, go with the chips what are used in reference boards - you know they work and you know there is software for it.

Paul van Avesaath , 08-28-2019, 07:55 AM

also in your question you say that some one else is choosing the main components, so why do you not ask him or her?

MustafaE , 08-28-2019, 08:03 AM

Thanks for your responses. I meant some other people chose boards and processors on more general concepts such as clock frequency, ram size, etc.

Paul van Avesaath , 08-28-2019, 11:52 PM

Hi I understand, but are those not the people you want to learn from? can you ask them why they chose these specific parts.. let them know it is so you can learn from them...or is that not an option

MarylinPurtill , 11-20-2019, 08:09 AM

That's really helpful. As a beginner in PCB, I will also get the benefit from it. But it would be great if you share some online channels where soldering reflow oven is being taught.