Building a mother board

[shine]

Does any one know where I can go to find out the exact name and number of chips, capacitors, resistors and other electronic part I would to build a motherboard from scratch. Or if anyone has done it in the past could you give me advise on the project.
I am just doing the project to learn more about the inner workings of a computer. I will be doing it with a group of friends and we have all assembled computers before and have basic knowledge of electronic circuits.

[Paul V]

I was actually talking to a group of people on this before. The big problem is running all the traces on the board. It would take many many many hours to do by hand, so unless you have an automated way of doing it, you'd have problems.

The best way, if you wanted to proceed, would be to simply copy an existing board. You can trace out all the traces, from that you can do a schematic if need be.

Board design by hand is rough stuff. if you want to proceed do keep me posted by email -- I've done my share of assembly and HW design, so I can probably help you to some degree.

If you want a custom system, then you need to completely design a computer architecture from the ground up. How many CPUs do you want? You will probably not want the overbloated x86 type CPUs, but will want something that uses a RISC architecture.

Then you need to figure out how you want to handle the MB architecture. You will need to program a BIOS for yourself, and you will need to implement PCI 2.1 and ISA buses, and AGP if you can do it. Overall this could take a long time to do.

As to how many resistors, caps, etc. you need -- the question is how many DO you need? However many you have to put on your board to make it work, however many you need in your schematics. There's no right or wrong way (although there are smart and not-so-smart ways)

This probably is not the right forum for this post though?

[This message has been edited by Paul V (edited 02-08-2000).]

[socalgal]

Beaming over to Motherboard Forum...

[800XL]

I've had some exposure to circuit board design, and it is not something you can really duplicate in your garage. Modern motherboards require very controlled signal quality and timing. Connecting wires to a breadboard just cannot duplicate what is done in your average motherboard with a multilayer PCB. Trace lengths affect timing, placement of traces in different layers affects signal noise, etc. Unless you want to design a board, spend a lot of $$$$$$s to get even just one built, then spend that cash again when you discover a problem with the board layout, buy many $$$$s of test equipment, etc, etc.. I suggest you tackle something a little lower on the scale. Home brew electronics just can't build a motherboard to compare with anything put out in the last two decades.
I've seen people come up with this idea every so often, and I like the initiative it shows. However, you can generally figure that if you have to ask, you are not prepared to take the plunge. Start researching parts vendors, reading datasheets, learning some CAD, and build some Blinky Light Computers (simple circuits to blink LEDs in cool and annoying ways) instead of going head on at building a motherboard. The needed tools alone would buy you a house, or ten.

Some good reading:
developer.intel.com

Look especially at the data sheets and design guides in the chipset and processor sections. That should give you an idea of what you are up against.

[chc]

All though the advice you have gotten on this topic is excellent, if you are looking for a good and fun, do-able, and relatively inexpensive way to home-built a motherboard, it can be done, at least if the components are still available.

For several hundred dollars, you can wire-wrap a slow-speed motherboard (less than 4 MHZ). You are not going to build a DOS or PC-compatible system this way, so if that is what you are looking for, forget it. If the chip is still available, you can build a Z80 based single board microcomputer, and design it to do some specific task. You will need an EEPROM burner or at least access to one, and half a boatload of discrete components. You will need to learn Z80 assembly language, and find a cross-assembler (ie, a piece of software that runs on a PC but assembles code specific to your microprocessor). Also helpful to have a logic probe (can get at Radio Shack probably) and a half-decent oscilliscope (the logic probe is required, the O-scope is just helpful).
Many of our current-day computer gurus have little stomach for the detail and design involved in a project like this, but you can't beat it as a learning experience.
I have done this (successfully) before, and I am not an EE, nor even truly qualified as an electronic technician - but I do read alot and am self-taught in most of what I know. I say all that to say that if you are motivated - you can do it too!
Anyway, I can give you more details if you are still interested, including some sources of parts. Just email me at ccobb@wts.edu

[Banti]

Use Altera and Xilinx chips to make the major componets. The graphical design with these packages are the exact same that real designers use in the workforce.


Banti

[alondra]

800XL and chc gave some good advice here. years ago before solid state I built some simple circuit boards, draw lines with acid resist, acid remove the rest of the copper and then remove the acid resist,drill holes for the wire thru components. I gave up ham radio when components were no longer available. take a close look at a circuit board today,(with a magnifing glass). those traces are verry small and close, and most of the components are surface mount, my son is CEO of a company that mfg. boards, and the surface mount mach. is as long as my living room and cost as much as my house.the placement of each component is placed by a comp.program. and all robotic, a human could not do it. If you could get wire thru components the board would be as big as your dining room table. remember some of those tiny chips contain many components.