[coreboot] 486 Motherboard from scratch
rexoregan20 at yahoo.com.au
Fri Nov 23 13:26:55 CET 2012
Thanks for the input. I have only really done much software before too
so this is a big jump for me.
Those numbers (8042 - keyboard + extra bits
8253/8254 - Timer
8259 - Interrupt controller
8237 - Possibly you might need DMA controller if you want to use floppy etc)
are the identification numbers of the chips themselves right?
On Fri, 2012-11-23 at 10:57 +0100, Rudolf Marek wrote:
> > How hard would it be to design, source components and construct a
> > motherboard for something simple such as a 486DX from scratch?
> I'm the software guy but, I think you don't need the chipset, maybe 80386SX with
> static ram aka 62512 and some simple decoders would be good choice. For dynamic
> RAM you would need some controller. For the "legacy" PC i think you need to
> 8042 - keyboard + extra bits
> 8253/8254 - Timer
> 8259 - Interrupt controller
> 8237 - Possibly you might need DMA controller if you want to use floppy etc
> Maybe doing this in some CPLD/FPGA would also be an option.
> For the bus, I would choose ISA...
> 80386SX has 16bit bus so not so many wires. Sufficiently low clocks.
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