KFA-4000ATX - design your own Amiga

[bebek]

One day I thought I will have to learn PCB design.As I know basics I thought I have to do something bigger. I have this stupid idea to make Amiga 4000 ATX. As I do not have much free time it took me a year to transfer the circuit diagram with some modifications to PCB design software and compile it. Actualy I have done it twice. First time I did it "free style" using components from available libraries but when I finished it was not very professional and messy so I have started again from a scratch. I learnt more about software and created my own libraries with Amiga components and foot prints (only a few foot prints to go) and I am very close to placing components on PCB.

Firstly I wanted to implement Prometheus PCI bridge on it but it would be used only for Voodoo card so do not think it makes a lot of sense (although have not scrapped this idea yet ).

How I see it:

- circuit diagram is based on A4000T, A4000CR and A4000B
- PCB full ATX size board - that may change,
- only pin headers for serial and parallel ports on mainboard,
- no Video Slot or ISA slots
- depending on space on PCB 3-4 Zorro slots but due to board sice restrictions I do not think I will be able to fit Zorro slots for full size cards,
- was thinking about implementing socket for 060 GBA1000 card instead of difficult to source CPU socket or implementing 3640 card on the mainboard with 060 modification
- PS2 or USB socket for mouse (not sure which one is the best and available as open source)
- 15-pin VGA type socket for RGB output
- no audio filter
- M6242 clock
- SIMM socket for 2MB chip and 1 or 2 SIMM sockets for FAST memory
- depending on the size it will be 4 or 6 layer board, aiming to have components on one, top side only but it may happen that on two.

As I do not have much time for surfing and looking for additional circuits I could add I would like to ask members for some help in this matter, ideas, directions, links etc.

I will also need somebody who can read circuit diagrams and understand how it works to help at some point to verify final circuit diagram. I do not want to pay loads of money to manufacture PCB that got errors on it.

What would you like to add to this board? (within reason ).

[BigFan]

USB, SATA, PCIe.

[bebek]

Originally Posted by BigFan

USB, SATA, PCIe.

You have missed: "within reason" .

[BigFan]

No, i didn't. But sorry for stressing you.

Where to attach hard disks?
GBA has Oktagon 2008 like IDE ports.
And i'm not interested in hardware that doesn't a minimum of connectivity. USB, NIC is somewhat mandatory.
Where do you get your custom chips from? AGA is smd only, nothing socketed.

Printer, mice, scanners, keyboards, all on USB today.

[bebek]

Originally Posted by BigFan

No, i didn't. But sorry for stressing you.

Where to attach hard disks?
GBA has Oktagon 2008 like IDE ports.
And i'm not interested in hardware that doesn't a minimum of connectivity. USB, NIC is somewhat mandatory.
Where do you get your custom chips from? AGA is smd only, nothing socketed.

Printer, mice, scanners, keyboards, all on USB today.

The IC's can be recovered from damaged beyond repair A4000/A1200 boards, no sockets is a plus - no intermittant problems.

I am not trying to build/design a new Amiga, the goal is to make A4000 Amiga like for ATX case without need of buing expensive processor cards, small additional devices as it will be all in one.

I am looking for help with finding best solutions for USB/PS2 mouse, some helpful ideas about what to include, what is not needed from original design. Maybe different PCB format for different case that is also more popular and cheaper that A4000 case.

It is not commercial project, something for fun really. Can not even promise that it will be finished but it is quite evolved and I have not gave up for over the year and still see it interesting.

USB, NIC can be added with Zorro cards - not everybody needs them to have fun.

Hard drive connection is same like in A4000.

[jezry]

Great project. I have been playing with something similar
but i have not been very succesful with it. Looks more like my kids been playing :-) One thought matx would be even better.

[bebek]

Originally Posted by jezry

Great project. I have been playing with something similar
but i have not been very succesful with it. Looks more like my kids been playing :-) One thought matx would be even better.

mATX would be better but there is a lot to fit on it . Not sure if even 6 layer board will be enough ...

[jack-3d]

I have just my A4000T on recap and I was just thinking it would be perfect instead of ISA slots to have PCI from Prometheus or Mediator. Because Mediator on A4000T is strange looking and Amiga deserves proper solution. Voodoo3 is still easy to find and cheap graphics card and who does not want it, he can go with classics. I never had Prometheus, but as far as I know it supports also FM801 and RTL8139 right?

[Locutus]

Not to sound bad but.

Do consider very well if you have the board layout skills for this, a naive relayout of the existing a4000 schematics with some extensions integrated is not exactly a trivial undertaking that will 'just work'.

Look at Amigadigital's A550 (or whatever it was numbered). As much as i commend his insistence, that never was going to fly.

[bebek]

Originally Posted by jack-3d

I have just my A4000T on recap and I was just thinking it would be perfect instead of ISA slots to have PCI from Prometheus or Mediator. Because Mediator on A4000T is strange looking and Amiga deserves proper solution. Voodoo3 is still easy to find and cheap graphics card and who does not want it, he can go with classics. I never had Prometheus, but as far as I know it supports also FM801 and RTL8139 right?

It would be useful only for voodoo really , shame cause it has a potential.

Originally Posted by Locutus

Not to sound bad but.

Do consider very well if you have the board layout skills for this, a naive relayout of the existing a4000 schematics with some extensions integrated is not exactly a trivial undertaking that will 'just work'.

Look at Amigadigital's A550 (or whatever it was numbered). As much as i commend his insistence, that never was going to fly.

I am fully aware of it. This is a part of my self training. If you are able to help in this matter and offer advice it would be most welcome.

[rikbliz]

(deleted)

[jezry]

Didnt mean to criticise. I love this kind of projects:-) And if you make an atx board thats awesome!

[Stedy]

Hi,

Good luck with your endeavour, it will be a long and tricky path. A quick rough estimate is about 500 hours effort to create a PCB and procure components and perhaps assemble a board. Ensure you have the time and commitment.

I like to encourage people to design electronics and learn along the way but with experience, you learn to sit down and plan and estimate a larger project. I made a mistake a few years back, put in over 1000 hours on a project, that did not make it. All I have left are some prototypes and an aversion to certain Amiga forums where I got seriously flamed.

Some good PCB design tips here:

http://alternatezone.com/electronics/pcbdesign.htm (writtedn by the guy behind the EEV blog).

Have you priced up PCBs yet?

A single 6 layer ATX PCB (305x244mm) would cost £670, a batch of 3 PCBs would be £800.

What CAD software are you using?

[bebek]

I have already learnt a lot with this project so even it will not work out it will not be wasted (providing I will gave up before spend money on useles PCB )
At the moment I have an access to fairly cheap PCB manufacturing but wait with a price when PCB format/size is set in stone.

Thanks for the link, very useful.

I am using Altium DXP.

Stedy, what was the project of yours?

Originally Posted by jezry

Didnt mean to criticise. I love this kind of projects:-) And if you make an atx board thats awesome!

Was that a criticism? I have not noticed .

[jezry]

No it wasnt :-)

[gulliver]

In my humble opinion, cost saving, and simplification features, will lead to an affordable and reasonable desiggn for evreryone to use and reuse.

Just to name a few features:
-1MB flash rom for kickstart use and customization
-No RTC just the A1200 clockport header (cost reduction and increased expansion possibilities)
-No keyboard, serial and parallel ports - Integrate a Thyclacine USB open source card for those
-No Zorro slots at all. But an expansion card edge connector for adding a zorro daughter card with buster chip if needed (huge cost saving feature)
-1 simm socket for fastmem (no need for more when you can use one 1MB - 128MB simm)
-No simm sockets for chipmem (just soldered chips, since you will be always needing chipmem to boot)
-68040/60 socket with jumpable power source selection (3.3v - 5v).
-Customizable cpu clock generator (25mhz - 110mhz)
-audio out with a stereo jack instead of two RCA connectors (cost saving feature)
-floppy disable jumper (with just a diode that disables the default floppy drive when not needed or present)

[bebek]

Clock itself is not cstly and does not take loads of space but I will include clock port anyway.

Thought about Thyclacine USB but it is quite slow and take some space, more thatn keyboard connector .

I think Buster IC is needed in AMiga 4000 architecture otherwise it will not boot ?

One FAST memory socket is possible but have not seen design for 128MB on it, is there any around?

CPU voltage will be switchable, ATX PSU will provide both 5V and 3.3V.

Got audio on stereo jack .

I want to keep SIMM socket for CHIP ram - easier to solder, takes less space and easier to replace when memory dies .

Good idea with floppy switch - completely forgot about it, thanks.

I thought about at least one Zorro socket for GBA picasso board but granted, more can be on additional daughter board.

[Mrs Beanbag]

i was only talking about something like this with Alex this week.

my thoughts so far:
* Micro ATX or even Flex ATX board size (A1200 board should fit easy on Micro ATX, it is quite wide but not very deep), possibly even a board that will fit in either mATX case OR an A1200 case (I will have to make a mockup of this on acryllic sheet or something but i'm convinced it is possible).
* Use a modern replacement flash ROM chip instead of the original Amiga ROM chips, perhaps even a custom ROM (maybe we could negate the need for a physical floppy drive switch in ROM)
* implement glue logic including CIAs in FPGA (this logic is very simple and should not require an expensive FPGA) could also implement new functions in here, such as turn off power by software. This way we can also scavenge A1200s with dead CIAs which i gather is very common. Get the Verilog code from Minimig project!
* PS2 mouse port (maybe not USB because it won't really be a USB port and there's something i find unsatisfactory about that for some reason)
* Hybrid A1200/A4000 design. Use IDE interface from A1200. Use 68060 modified 3640 schematic, integrated on board (no socket).

[pandy71]

I see no sense to recreate board with unresolved problems related to architecture (such as limited bandwidth for CHIP mem). Anyway good luck.

[Mrs Beanbag]

Originally Posted by pandy71

I see no sense to recreate board with unresolved problems related to architecture (such as limited bandwidth for CHIP mem). Anyway good luck.

hmm, maybe it IS possible to solve that, also perhaps break the 2Mb Chip RAM limit (8Mb should suffice - without Zorro expansion space we could use 0x000000 to 0x7FFFFF)