New classic mainboard

A1000 replacement

Georg Braun (gb97816) released an updated version of his selfmade A1000 mainboard.
The latest version includes an extra adressline on the PLD for further 32 bit memory-expansions.
There is internal connector to feed in a vga-signal from a "undone" internal graphiccard.

Other (allready known) features:
68030/68EC030 @ 50 MHz support
68881/68882 @ 50 MHz support
(successful tested with up to 60MHz !!)
8MB 32 bit fastmem / 0 waitstaits
ECS-Agnus with 2MB ChipMem
ECS-Denise
Amber-FlickerFixer
realtime-clock
1MB flashmemory for drivers and addons
internal ZorroII connector
IDE-connector

For more details:
www.amiga.org
www.a1k.org (german)

@Ratte

She's a beauty :)

@Ratte

Cool stuff, not all that hot in terms of performance, but cool anyway.

@Ratte

Looks really nice, where professional assembled.

If you?re able to assemble and design a computer like that you most be able to design some thing more powerful things :D
Please design me a CELL computer whit 2Gbytes RAM, PCI slots and SATA controller :D

@LiveForIt

Quote:

If I may reply on this quote, electronic hobbyist with some knowledge as I am :)

The main problem with designing something fast and modern is not the logic, how to get all the signals correctly connected between all chips and stuff. I'm sure this guy can logically design what you propose (CELL, 2GB RAM etc.). I might as well be able to do it.

The main problem is to get the electrical characteristics correct. At one GHz and above it is for example absolutely crusial that all wires from the memory controller to the actual RAM chips have exactly the same length (which must also not exceed some maximum of a few centimeters). How do you solve that with 64 wires of data, 32 wires for address, and a few others??
You must also have a compatible impedance for both the controller and the RAM chips, otherwise you get either a too weak signal, or signal reflection, with memory errors as a result. The impedance depends on lane width and how close it is to earth planes etc. (Do we know about a computer which has trouble with this..? Yes we do, it's called AmigaOne, and its RAM only runs at 133MHz.. ).

At these frequencies all signals emit quite a high level of radio noise as well resulting in cross-talk and bad signals. This must be taken into the equation too about where you can route the signals on the board, how many earth planes you need to cancel out noise etc. etc.

You need a very advanced autorouting PCB tool to accomplish this unless you're extremely good at it.

Take a look at a modern motherboard (the AmigaOne will do) and you see that a lot of signals, expecially around the RAM and CPU, are routed in zig-zag for no apparent reason. Well, the reason for this is to keep all lanes at an equal length. And, as I said, that's just one aspect.

@orgin


Georg build the fastest 030-Amiga i have ever seen ...

This picture is from the 60Mhz testrun (sysinfo untruly reports 66MHz)

@Ratte

If you have an old A1000 that is dead or dying, and you REALLY, REALLY need to keep it going, this is a neat solution.

With an '030, you could even upgrade to OS3.5/3.9.