I'm trying to find some resources on designing motherboards, but there doesn't seem to be much out there. I'm also looking for information about interfacing with an Intel 80486. I mostly understand the datasheet of the Intel 80486, and I'm already familiar with x86 asm and the x86 architecture, but there isn't much out there (that I could find) in terms of a high level initialisation / execution overview. I'm also not sure whether a full-blown BIOS is a requirement, or whether I could cheat my way out of using one (i.e. replace it with an AVR microcontroller or similar).
My end goal is to build something that runs DSL. What I'm aiming for isn't a full extensible board with PCI/ISA slots and USB support, but rather a complete bare-bones board that will run the OS. I'd be going for the absolute minimum requirements - CPU, RAM, basic GPU, IDE controller, PS/2 interface.
I'm aware that this is a hugely ambitious project, and will probably end up taking me several years, but it's something I've got a lot of interest in.
Any good resources for this level of stuff? Surely the guys who design modern motherboards must learn it from somewhere!
I'm not trying to come across as conflictory here, but I just want to take a second to pre-empt the nay-sayers. I fully understand how complex and insane this project is. I get that I can't just breadboard this stuff up - it takes a lot of time and money to do it at all, let alone do it right. I know there are a multitude of issues that make this kind of circuitry difficult to deal with - high frequency, high current, low noise requirements, tight tollerance requirements, high pin/trace density, lack of datasheets, proprietary requirements, etc. I'm still dedicated/insane enough to give it a go. I'm not asking you to explain how to do it, I'm just asking for some links to websites or books that deal with this kind of thing. I'd be extremely grateful for any useful information I can get.