Please help me design a motherboard

[Mikemk]

This isn't exactly about OS development, more about hardware devlopment...

I am building my own laptop, and found out that the motherboard for a laptop has to be designed based on the case. So, I am designing my own motherboard. The thing is, I have no idea how a motherboard works. (I know about transistors, diodes, resistors, capacitors, etc.) My question is, 1) How do I interface everything together (The cpu, graphics cards, ram chips, etc.), 2) What FREE software would you reccomend for designing it (I'm currently using DesignSpark), and 3) What manufacturer would you recommend for getting a quantity of one built at a fairly cheap price?

[bluemoon]

So, I am designing my own motherboard. The thing is, I have no idea how a motherboard works

People cannot tell you how it work by a few line of text, just as nobody can teach you how to build a rocket in a forum.
You can't build a motherboard with none knowledge and do it in one step, there are much to learn.

[Mikemk]

there are much to learn.

Then, where can I go to learn?

[Combuster]

If you have never built something around an arduino or, even better, manually wired up an Atmel chip, building a motherboard is like playing the sorceror's apprentice: it will make us have a good comedy night and end you up with frustration.

The previous newbie asked this: http://forum.osdev.org/viewtopic.php?f=11&t=25106 You'll find some pointers in there.

[rdos]

The simple answer is that you no longer build motherboards yourself. This is partly because the chipsets in modern computers are too complex, and partly because these chips require professional PCBs that costs many times more to manufacture in small series than a ready-made PCB with components mounted costs. Additionally, chances are your construction won't work the first few times either, multiplying the costs. Some of the required components are also hard-to-get, and few, if any, companies have them available for sale. Even if they have them, they will cost you multiple times more than a motherboard manufacturer pays.

Edit: Just to give you an idea of the cost of small-series PCB manufacturing, the solar panel PCB I discussed in the other thread, which is considerably smaller than a motherboard-PCB, costs me about $500 for 5 pcs. If I instead had ordered 10 pcs, it might have costed $550. The initial cost for doing a PCB is often higher than the cost for a motherboard, and then you also need the components and mounting them.

[Yoda]

m12, are you joking??
The design of a modern mainboard is the task for a team of professional hardware engineers for at least a year of full day work. Even designing a new extention card takes me up to half a year.

[VolTeK]

If you have never built something around an arduino or, even better, manually wired up an Atmel chip, building a motherboard is like playing the sorceror's apprentice: it will make us have a good comedy night and end you up with frustration.

The previous newbie asked this: viewtopic.php?f=11&t=25106 You'll find some pointers in there.

People cannot tell you how it work by a few line of text, just as nobody can teach you how to build a rocket in a forum.
You can't build a motherboard with none knowledge and do it in one step, there are much to learn.

Are your answers.

[rdos]

It could even argued that without having done an OS that uses a considerable amount of typical mother-board ICs, you wouldn't have the expertise required in order to complete the task. Therefore, the prefered way of doing it is to first write an OS for a standard PC, and then start thinking about doing your own motherboard. Of course, once you understood the complexities of modern processors and chipsets, you might decide that building your own motherboard might not be such a good idea after all.

Another factor is that a modern motherboard is an extremely high-frequency device, which means that wire routing and such could make a big difference. It would not be enough to construct a correct schematic of the project, but rather you would also need to consider wire routing, power and ground planes and such.

[Mikemk]

I have programmed an OS.

[Rudster816]

You can't design a motherboard for a modern computer, you'll never be able to get your hands on the proper documentation to be able to get anywhere. Chip manufactures don't just publish the full spec's for their chips on the internet for anyone to look at. They also won't pay any attention as a customer because you have no money, and the quantity of chip's you'd be asking for would be laughable.

As a frame of reference, it took over a year to get the final Raspberry Pi PCB laid out. A full on x86 motherboard is wildly more complex.

If you want to design your own laptop, find a motherboard on Ebay (or some other place) and design a case for it. That's your only option. Even doing that requires considerable skill, and getting a physical product will cost quite a bit.

[miker00lz]

as has been said already, it's basically impossible to build a modern motherboard. if you're really interested in designing something that you can call a "PC motherboard" though, get some components from old dead 8088 motherboards. desolder parts. then read hundreds upon hundreds of pages of datasheets and other documentation. design an 8088 motherboard circuit. build it.

even that is a hell of a job, and that's late 1970's technology. i don't think you understand how complicated this stuff really is.

you might want to look into designing something like a 6502-based SBC, though. that is very reasonable. in fact, i've done it. i made a sort of "parallel port" out of 74LS373 chips on it too, and i used an old 486 laptop as a terminal into it. i had it working in a couple weeks.

check out www.6502.org for tech specs and ideas.

[ACcurrent]

Get hold of a beagle bone and load some linux distro onto it.
Creating a full scale x86 motherboard is crazy particularly if you do not have the know how and man power.
Another option could be to use an FPGA board. Build your own CPU and graphics card. Then build an assembler for it.

As to teach people how to build a rocket, there is this project frednet that has no funding but says they are going to win the Google Lunar X prize (relying on opensource lol).

[Firestryke31]

Damn it's been a while since I last posted here!

Anyway, if you're just looking to build a computer to say "I built a computer from scratch, and I mean seriously" you might want to check out this little project. While it's based around a Motorola 6502, it shouldn't be too hard to use the basic concepts for a Z80 or early Intel CPU. From there, it's mostly just adding support circuitry. A true bare bones MoBo is probably just a North Bridge, South Bridge, RAM and CPU, with almost everything else being addon PCI stuff (albeit a lot gets integrated into one of the bridges, and is where a lot of the complexity comes from).

Finding a pinout for even the Intel i7 (see pages 37-51) isn't hard (that example was almost literally "Google and click the first link"), and the startup sequence for x86/x64 is pretty well documented, so a lot of your problems (read: almost all of them) are going to be deciphering product documentation, support circuitry, and board design and layout. And the risk of burning up a $300+ piece of equipment.

[visio]

Don't jump from one place to another place. First you have to understand the in and out. Do you know low level programming?

[ACcurrent]

Well one could alwys take a peek at open compute's PCB cad files to see the mother boards facebook uses.