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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:

How would i be able to design the motherboard (in an app), and what would be my ways of producing one for myself.

I would like a link to a good and (fairly) easy to understand tutorial too please.

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Him
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    If you don't know how a MB works you can't design one. Better go do something else. – stevenvh Apr 15 '12 at 15:18
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    One will probably cost you twice as much as two. NRE is the same. – Federico Russo Apr 15 '12 at 15:19
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    An MB brings a few aspects of electronics with it that you probably never heard of before. How are you going to debug it? Start with something simpler. – jippie Apr 15 '12 at 15:21
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    I am going to debug it on a breadboard, and I have made calculators, etc. before @jippie – Him Apr 15 '12 at 15:25
  • Ah ok, save yourself 4 - 500 $ and see if you can make it work on a breadboard first. What clock frequency do you have in mind? – jippie Apr 15 '12 at 15:28
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    A PC motherboard on a breadboard! No, don't close this question, this is gonna be fun! – stevenvh Apr 15 '12 at 15:31
  • 4.0 Ghz. And, to make the computer, I will need to pay for one. My main question is, how to place the parts, or the ports, on the schematics and the pcb design. – Him Apr 15 '12 at 15:34
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    You're two weeks late for this question. – avakar Apr 15 '12 at 15:35
  • explain @avakar – Him Apr 15 '12 at 15:36
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    It's so obvious that you don't have a clue of what you're talking about. Nobody can make a digital design with the complexity of a MB work at 4GHz on a breadboard. Nobody. – stevenvh Apr 15 '12 at 15:36
  • I'm aware that the breadboard ersion won't be as powerful as the final product. Could someone, please answer this question? – Him Apr 15 '12 at 15:38
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    Hey, no probs mate. Here's a schematic. Should make your life much easier: http://repair-notebook.com/download/schematic/Toshiba/Toshiba_a200_la_3661.pdf :D – Armandas Apr 15 '12 at 15:50
  • @Armandas - So far for confidential information... :-) – stevenvh Apr 15 '12 at 15:55
  • Armandas' schematic is interesting. Especially for breadboarding. None of the components is 0.1" PTH... – Federico Russo Apr 15 '12 at 16:02
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    You have to admire OP's optimism :D – m.Alin Apr 15 '12 at 16:03
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    @m.Alin: I'm not sure. I have visions of straitjackets... – Federico Russo Apr 15 '12 at 16:14
  • "I am building my own laptop" Oh no, you don't! – m.Alin Apr 15 '12 at 16:49
  • So are you in talks with Intel/AMD? You do know that the full documentation for their chipsets is under NDA, right? Also, do you have the (many) thousands of dollars required to purchase the full spec documents for the various busses you intend to use? – Connor Wolf Apr 15 '12 at 17:03
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    So, what about the companies that can be hired to design it for me? are they any good? – Him Apr 15 '12 at 17:32
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    @Him - Some will be better than others. Ask references. Be prepared to pay tens of thousands of dollars, maybe a hundred. – stevenvh Apr 15 '12 at 17:48
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    Actually, I think a motherboard design would be 100s of 1000s of dollars. There is a lot to get right, test, etc. Now that I think about it, it doubt a design house could to this for under 1 M$, if they even knew how. The only chance for less is if it's a modification of a previous design, but that is one reason companies that have such designs guard them so carefully. If someone came to me to design a motherboard from scratch, I'd most likely turn down the job. – Olin Lathrop Apr 15 '12 at 17:52
  • @Olin - yes, When I thought about it I realized it's a bit cheap, but then you already replied. I remember paying >10k for a 6cmx6cm 500MHz design. And that's just the layout. – stevenvh Apr 15 '12 at 17:56
  • The thermal sensor part doesn't look too complicated? – jippie Apr 15 '12 at 20:10
  • Someone upvoted this! – stevenvh Apr 15 '12 at 21:01
  • @stevenvh I didn't up vote it, but I was tempted to. – Rocketmagnet Apr 16 '12 at 11:43
  • @Rocketmagnet - Why? Do you see any sense of reality in it? Dreaming is OK, but this really goes far! – stevenvh Apr 16 '12 at 11:46
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    @stevenvh I actually can't remember now. I think it's because It's still a useful question+answers for other people to read if they are considering making something like this. – Rocketmagnet Apr 16 '12 at 12:08
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    Ok, so I'm in a hospital and I see a guy getting wheeled by on a gurney, blood spurting out of his neck. Now I'm not a surgeon but I figure I'll go investigate, so I head in there and grab some tweezers... – MickLH Jan 03 '16 at 20:07
  • @stevenvh Someone apparently did manage to build a computer using a breadboard: https://eater.net/6502 – Adrian Jun 30 '21 at 18:22

4 Answers4

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I hate nay-sayers more than anyone, and I'm all for undertaking difficult projects.

BUT

Designing and building a motherboard is Extremely difficult. Even if you already had great EDA software, and even if you already knew how to wire up the chips, the designing, building and testing process is about as hard as it gets.

It's a bit like asking: "I'm trying to do my own moon mission. How do I make gunpowder?"

Rocketmagnet
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You should learn what's realistic and what's not, and know your limitations.

You come up with a price of 400 - 500 dollar for a couple of PCB's, but you don't seem to realize that these are just the PCBs, without any components, and without the cost of the design (which you are going to do). That's what an 8 to 12 layer PCB the size of a motherboard costs. You don't know that.

You don't know what components or subsystems a motherboard contains, you only know its mechanical dimensions (fit inside your DIY laptop). You have no clue about design tools: DesignSpark doesn't even get you started. You don't know why that is.

You don't know how to start a high-speed design, and what kind of pitfalls you'll encounter. I mentioned impedance matching, you don't know what that is and why it's important. You don' know what a transmission line is.

You want to breadboard the design, but you don't realize that you can't even make the system work that way, not even at 100MHz, let alone 4GHz. If you would be able to make a digital design at 100kHz you don't know how to scale it to 4GHz.

You don't know that none of the components and subsystems is fit for breadboarding. (Do you know what an LGA is?)

Do I need to go on?

stevenvh
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If your goal is to design a modern PC, forget it really.

Modern chips interface with busses like PCI express or high-speed differential busses. You can't breadboard this up, no way. Frequencies are from 100MHz up to several GHz. A breadboard will probably 'fall apart' at a couple of MHz (I can't even get my serial port to work at 3MBaud on the heavily used breadboard I got). Even routing boards with these speeds requires a lot of knowledge and know-how.

Other than that, the exact pin-outs of some chips are hard to get. Where are you going to find the pin-out of a chipset? How are you going to prototype this? Your question of an one-off motherboard an fairly cheaply is a contradiction itself. A one-off is not cheap, never will.

The DesignSpark toolkit is hilarious for any PCB more than 2 or 4 layers. You know modern computer motherboards use atleast 8 layers? There are some figures of like 12 or 16 I believe. You also know they are designed with multi-million EDA tools to verify signal integrity, PCB design, etc.? You also know that they are not designed by one person? As a one-off these costs not hundreds to produce, probably thousands each (may even be underestimated). Only in production where ten of thousands are produced, they become affordable.

Anyway, if you intend to learn about the workings of a motherboard you probably should look the theory up of high-speed PCB design such as differential routing pairs and multi-layer routing, multi-phase switch-mode power supplies, phase locked loops, BGA's, power supply decoupling, seperate/local ground planes, and a bunch of other stuff. Most of this what I called can just be applied to PCB design. Th schematic is just figuring out what the pinouts are, how chips should be interfaces, power supply requirements and practical production requirements. As I said, pin-outs of some chips or the workings can be proprietary (however I do know you can find the Intel CPU's pin-outs on the internet).

Look, if we all could do this you would see projects all over the internet with people 'hey, that guy stuck a Celeron on his line follower robot!'.

stevenvh
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Hans
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    Can you suggest a program to use, then if DesignSpark isn't very good? – Him Apr 15 '12 at 15:45
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    I am not saying DesignSpark is any good, I am just saying it's not good for the purpose of designing complex boards which a high-speed design requires. It will probably fit the bill for hobbyist use, just like Eagle, TinyCad, KiCad and a bunch others do. 'Proffesional tools' would be like Altium designer, Mentor graphics or Cadance Allegro.. but they are very hard to use and very very expensive. – Hans Apr 15 '12 at 15:46
  • What about AutoCad electronics? – Him Apr 15 '12 at 15:48
  • AutoCad is for mechanical engineering, so I figure the electronics edition is for wiring up machines and industrial installations (relays, PLC's and big stuff). – Hans Apr 15 '12 at 15:49
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    What do corporations like Intel use to design motherboards? – Him Apr 15 '12 at 15:50
  • @Him - Autocad?! This is getting worse by the minute. Listen pal, two words: "impedance matching". Just to name one of the problems you'll encounter, and of which you don't have a clue. The EDA packages Hans mentions can handle that, Autocad probably can't, and you most certainly not! – stevenvh Apr 15 '12 at 16:26
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    @Him: I think what everyone is trying to get at (and what you should have picked up on by now) is that the tool you use doesn't matter when you don't understand, more importantly, what you are actually trying to do. Building a MB is much more difficult than using discrete components and choosing the right software package. – Chris Laplante Apr 15 '12 at 17:43
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    @Him I think the thing which you want to discover is http://en.wikipedia.org/wiki/Gerber_format

    http://en.wikipedia.org/wiki/Photolithography

    build your own pcb http://books.google.co.in/books?id=SoA4koYHRxsC&pg=PA130&redir_esc=y#v=onepage&q&f=false

    pcb design tutorial http://www.pcbexpress.com/technical/tutorial.php

    pcb design tutorial http://www.4pcb.com/free-pcb-layout-software/index.html and last but not the least watch a video here https://www.facebook.com/photo.php?v=10150163043113418&set=o.143393599022309&type=2&theater this should give you an idea of what you want to understand

     – Registered User Jan 01 '13 at 07:07
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This might help you a little bit. It will give you some idea of how much work goes into laying out a motherboard type PCB. But remember that this guy already knows all about high speed design, impedance matching, power supply distribution for high speed ICs, etc.

YouTube: Extreme PCB layout - DDR3 Interface

Rocketmagnet
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