ATX4000 - an A4000 DIY Motherboard - Information needed -- pls help out :)
 

Hi all,

I'm doing my own A4000 Motherboard in an E-ATX format. I always wanted one and these things are terrible expensive. This will be open sourced :-)

It would be nice if some of you give me a little help in finding documents or giving tips about the A4000's architecture Schematics --> bugs/errors in them etc.

Donations are welcomed too.

Things I want to know:

Footprint of CPU Slot --> http://www.amigawiki.de/doku.php?id=...s:cpu_cardslot --> Pinout http://www.amigapcb.org/
Distances of CPU Board Holders in relation to CPU Slot?
Keylock mechanism obsolete --> 8 Parts cleared out of schematic

Which Jumpers are obsolete? :

J100 --> CLK90 Source --> needed --> Delay Line will be edited in future Rev. --> need better Oscilloscope, mine only has 20Mhz bandwidth....
J104 --> CPU Clock Source --> needed
J151 --> ROM Speed --> probably needed
J212 --> Select PAL/NTSC --> needed
J213 --> Chipmem Size Select --> doesn't work anyway --> obsolete
J214 --> Alice Chipmen 8M --> doesn't work --> obsolete
J351 --> Internal Floppy Jumper --> needed
J352 --> Redirect DF0: --> probably obsolete --> Will Add Floppy Header for internal Floppy 3-4
J500 --> Sync on Green --> does anyone need this?
J501 --> Lisa Sync --> probably needed
J502 --> Select DAC Sync --> same as J500 Sync on Green --> anyone needs this?
J850 --> Enable DSACK --> there is no 68020 Accelerator for A4000 --> probably obsolete
J852 --> Select RAM Size --> needed

PS/2 Keyboard and original A4000 Keyboard support --> selectable via Jumpers
Port 0 Mouse/Joystick Switcher

Zorro Slots --> will be there in classic version.
Video Slots --> will be there in classic version.
ISA --> will be there in in classic version.

Formfactor with Zorro has to be at least E-ATX

Future things to be done:

2 Versions of Board --> ATX4000C <--> ATX4000E --- ATX4000C will be classic with zorro and video slots, this is the version as you'll get it first. Later an ATX4000E version will be added.

ATX4000C:
E-ATX formfactor --> Zorro Slots
5 Zorro Slots
2 Video Slots
5 ISA Slots --> for toaster and bridgeboard people.
Maybe a version later with Included 68040/68060 onboard.
Will be replacing GAL's with CPLDs in a future version
64MB/112MB Hack possible
Maybe support for bigger Roms in the future

ATX4000E:
Including 68040/68060 onboard
Replacing GAL's with CPLDs
Scrapping Buster --> Allowing for normal ATX or smaller formfactor
Scrapping onboard RAM except Chipram
Trying to split the bus, to allow native 68060 Bus speed --> 50/66MHz --> the slower half to Chipset --> faster half to a FPGA for PCI/PCIe and to Fast RAM
Adding fast IDE/SATA
Some other onboard stuff, if the PCI/PCIe Bridge works
Maybe support for bigger Roms

So for now:

To Do: Transfering Schematics in KiCad and simultaneously creating Bill of Materials --> done
To Do: Add Latch for Soft Power on/off --> Done --> Thx @Daedalus
To Do: Check if Footprints are Correct --> done
To Do: Component Placement on PCB --> in work
To Do: Route Prototype
To Do: Build Prototype
To Do: Probably some minor changes
To Do: Release

As it's just too much for myself as a first project, I uploaded it on github


https://github.com/elenachenchen/A4000-ATX



Thank you in Advance

Elena

I am sure there would be plenty of interest. This should get you started.

http://www.amigapcb.org/

hi,

take alook here:
Amiga PCB Explorer
Amiga PCB Explorer - beta - more Amiga models
amigawiki.de - schematics

#1) Magic was a bit faster :spin

Good luck Elena! Seems like a fun project. But are the components needed readily available?

I suspect the interest would be massive. I'd certainly love something like that.

I know that the Alice chips are in short supply though.

Very interested. You'll probably have to go eATX to fit full length zorro cards.

How long are the full length Zorro cards?

The hardware reference manual covers the mechanical specifications of Zorro cards here (click the links for the various possible configurations). They're basically the same size as full-length AT cards, but the Zorro connector is at the front of the case, not the rear. Essentially, the motherboard needs to reach around 300mm from the case's back panel in order to accommodate the Zorro connectors.

Is there any interrest in using PCIe Cards with a classic Amiga? Or is PCI the highest "usefull" interface? I stumbled over Prometheus. The next step would be to get this to PCIe via PCI to PCIe bridge, but the question would be if cards would be used by the community at all?

So for short:

5 Zorro Slots?
2 Zorro and 3 PCI Slots? Or even 5 Zorro and replace the ISA with the PCI
2 Zorro, 2 PCI and 1 PCIe slot?
2 PCI, 3x PCIe?
and so on?
What would be viable?

I think if i would really do that project, then i would want to go further than just a Standard A4000 in a box.

So now, where to start, where to end.....

:D

One word:
DRIVERS

Does not matter what connectors you have, if there are no drivers there is no point.

If you are serious on a board see if bebek got anywhere http://www.amibay.com/showthread.php...our-own-Amiga-)

If you are really serious adapt the Prometheus directly to the 68060 socket and develop the software so we can interface to something modern other than a VooDoo 3.

The only reason for having ISA slots is for use with a PC bridgeboard. Without that requirement, they can be ditched and replaced with PCI. As for PCIe, the only advantage for classics would be availability of cards - PCI already delivers more bandwidth than any classic can use. PCI Radeon cards are available and useable with current drivers in Mediator busboards, and other cards like USB, audio, network etc. are all still easily found in PCI format as well. While PCIe might be doable by patching PCI drivers for the same hardware, it's probably a lot more effort than is currently available in the community. So I would say to stick with PCI.

The Mediator 4000 has both Zorro and PCI slots, which could serve as inspiration.

A "standard A4000" in ATX format would be extremely popular, you could always redesign it with more modern features later? I'd go with whatever has the widest classic hardware support to start with.

Do whatever keeps you interested and motivated enough to finish the project.

People have all sorts of wishes, but it's not up to you to fulfill them.

add a SPI port - most promising thing for those fancy gadgets. :)

If you're actually doing a new motherboard then I'd suggest dropping the riser card and putting the Z3 slots directly on the board. Erm... you kinda have to do that to fit a pc case? Do Zorro cards fit with pc case slots in width and height and general placement?

Now is the time to do this. tborro over at Amibay is practically selling the entire A4000 chipset as NOS but he won't have many chips for long.

You say that but as Apollo core evolves *IF* they can get enough HDL developer interest then the entire Amiga chipset will be replaced. The FPGA's they use for Apollo have PCIe Gen 2.1 integrated into them.

I don't see that in the store - do I need to contact him directly?

Apollo is the outright definition of 'Developer Hostile'.

tbtorro is on Amibay, not AmigaKit :) He has several threads with various chips listed.