A4000 DIY Motherboard - Page 3

Chucky · 28 February 2018, 12:32

Serialport is important for DiagROM. (that will be very useful for debugging) but a db9 port. make it more modern.

external floppy. well I can handle without it. do as AmyITX, they have used unused pins of the internal 34pin floppyconnector to handle more drives. then people can do a connector by themselved for external. if they want to.

SnkBitten · 28 February 2018, 13:37

I'd definitely keep Zorro slots on the board, I'd love a new(er) A4000 motherboard for ATX cases but I also have a lot of Zorro II/III cards that I don't want to give up.

I'd want the A4000 experience.....Zorro boards, video slot, etc..

I agree with Chuck on changing as little as possible on your first design to make sure you have everything working, then start making your desired changes.

elenachen · 28 February 2018, 15:09

Yes i agree with changing as little as possible. But there are things that can be easily left out, because they aren't connected on Standard.

Does the A4000D need a Riser Board to work?

Zorro is neat yes. But won't be unhappy to let that work be in queue for next Revision. A running version would be nice first.

The 23 pin Video out is a pain in the ass too......

Which Pins aren't needed? I would opt for a D-Sub 15 instead if possible......but don't know if someone needs specific pins.

Any suggestions?

Bprepared · 28 February 2018, 15:13

Quote:

Originally Posted by elenachen

Yes i agree with changing as little as possible. But there are things that can be easily left out, because they aren't connected on Standard.

Does the A4000D need a Riser Board to work?

The 23 pin Video out is a pain in the ass too......

Which Pins aren't needed? I would opt for a D-Sub 15 instead if possible......but don't know if someone needs specific pins.

Any suggestions?

I would suggest configuring it like the Minimig scart as they seem to be becoming the defacto standard for modern expansions now. that way you can drop the RGBi and genlock pins. (unless anyone has particular wish to keep them in)

MigaTech · 28 February 2018, 15:15

Amigakit does an adapter that allows the 23 way RGB to be converted to suit 15 way VGA. OK so it doesn't allow all modes but it does work to a fashion. Perhaps you could get some info on what pins go where with that device?

SnkBitten · 28 February 2018, 15:30

Quote:

Originally Posted by elenachen

Yes i agree with changing as little as possible. But there are things that can be easily left out, because they aren't connected on Standard.

Does the A4000D need a Riser Board to work?

Zorro is neat yes. But won't be unhappy to let that work be in queue for next Revision. A running version would be nice first.

The 23 pin Video out is a pain in the ass too......

Which Pins aren't needed? I would opt for a D-Sub 15 instead if possible......but don't know if someone needs specific pins.

Any suggestions?

A riser "daughter board" is not required like the A4000T as the slots are on the motherboard. Video slot is good for Video Toaster, Scandoubler/flicker fixers, etc.. My Cybervision 64/3d with Scandoubler uses a video slot and Zorro slot and my Video Toasters use a Video slot (good thing the A4000T has two of those slots).

My thoughts are that if it's the A4000 you are duplicating, have the features an A4000 had in support of the boards available for the A4000 (Toaster 4000, Scandoubler/FlickerFixer's, etc..).

My A4000D is using Video (Toaster 4000) and Zorro (Picasso II).
My A4000T is using every slot available (both Video and all all accessible Zorro).

Just my opinion....

elenachen · 28 February 2018, 15:46

Quote:

Originally Posted by SnkBitten

A riser "daughter board" is not required like the A4000T as the slots are on the motherboard. Video slot is good for Video Toaster, Scandoubler/flicker fixers, etc.. My Cybervision 64/3d with Scandoubler uses a video slot and Zorro slot and my Video Toasters use a Video slot (good thing the A4000T has two of those slots).

My thoughts are that if it's the A4000 you are duplicating, have the features an A4000 had in support of the boards available for the A4000 (Toaster 4000, Scandoubler/FlickerFixer's, etc..).

My A4000D is using Video (Toaster 4000) and Zorro (Picasso II).
My A4000T is using every slot available (both Video and all all accessible Zorro).

Just my opinion....

Good thing to know, what's still needed in the Community. Thx!

Will most likely build a Prototype without that interfaces. And adding them after testing.

kolla · 28 February 2018, 18:42

Quote:

Originally Posted by Chucky

Serialport is important for DiagROM. (that will be very useful for debugging) but a db9 port. make it more modern.

I like those boards that come with built in rs232-usb chip, so just an "android cable" is needed to get serial console

elenachen · 28 February 2018, 19:06

Quote:

Originally Posted by MigaTech

Amigakit does an adapter that allows the 23 way RGB to be converted to suit 15 way VGA. OK so it doesn't allow all modes but it does work to a fashion. Perhaps you could get some info on what pins go where with that device?

Looked at the Pinout of that Adapter and the Standard VGA Pinout. I'll add a +5V line to it, to be sure old monitors work correctly and voila....^^

elenachen · 28 February 2018, 19:41

Hmm, on the Power Input Pins to the A4000D Boards is a _FAIL pin. Does the Power Supply hold that low till it's rails are stable? Or is there another reason for this, does the logic on the Board pull that low on failure? Maybe someone could measure that pin? Sry have no A4000 yet

MigaTech · 28 February 2018, 20:13

Quote:

Originally Posted by elenachen

Looked at the Pinout of that Adapter and the Standard VGA Pinout. I'll add a +5V line to it, to be sure old monitors work correctly and voila....^^

Ingenious !!

elenachen · 28 February 2018, 20:47

Quote:

Originally Posted by MigaTech

Ingenious !!

Well, at least if they're 15khz compatible. Scandoubler etc. is a thing for later. The minimig probably had no 5V rail to feed the 5V pin so they left it out.

elenachen · 01 March 2018, 10:42

So, the _FAIL line goes high if the PSU becomes stable. Are there any obsolete Jumpers? In which cases is sync on green used for example?

Ahh and of course it'll be open sourced ;-)

idrougge · 01 March 2018, 21:31

You should get a soldering iron, it might come in handy if you're going to build a computer.

Oh, and you need a motherboard and a processor as well.

elenachen · 01 March 2018, 21:49

A bit chaotic atm. Should be enough?

Building schematics in kicad for now. This'll take a while since it's a fun project and only spare time goes in there. Want to get as much information as possible about what's obsolete in the schematics --> like the 8M Chipram jumper in the schematics.... Don't want to implement such things later in PCB Layout.....

I'll give it my best!

MigaTech · 02 March 2018, 12:46

Some nice equipment there !!

Mick · 02 March 2018, 12:58

Best of luck and don't forget to keep us updated on progress!

NorthWay · 02 March 2018, 20:05

Why not have the connectors as internal headers with rows of pin pairs?
Then you attach a flat cable to a break-out connector in one of the back slots. AFAIK that is how Amiga tower designs have been.

elenachen · 02 March 2018, 20:12

Quote:

Originally Posted by NorthWay

Why not have the connectors as internal headers with rows of pin pairs?
Then you attach a flat cable to a break-out connector in one of the back slots. AFAIK that is how Amiga tower designs have been.

I want to use the ATX Shield if possible for that. Should be possible.

Still on first page.....this'll really take a while

MigaTech · 02 March 2018, 20:21

@elenachen, how big is this new board of yours going to be? I ask this as an idea of converting existing PC cases to suit your design.

28 February 2018, 19:41	#50
elenachen Registered User Join Date: Feb 2018 Location: Nürnberg Posts: 97	Hmm, on the Power Input Pins to the A4000D Boards is a _FAIL pin. Does the Power Supply hold that low till it's rails are stable? Or is there another reason for this, does the logic on the Board pull that low on failure? Maybe someone could measure that pin? Sry have no A4000 yet Last edited by elenachen; 28 February 2018 at 20:07.

01 March 2018, 10:42	#53
elenachen Registered User Join Date: Feb 2018 Location: Nürnberg Posts: 97	So, the _FAIL line goes high if the PSU becomes stable. Are there any obsolete Jumpers? In which cases is sync on green used for example? Ahh and of course it'll be open sourced ;-) Last edited by elenachen; 01 March 2018 at 14:19.

01 March 2018, 21:49	#55
elenachen Registered User Join Date: Feb 2018 Location: Nürnberg Posts: 97	A bit chaotic atm. Should be enough? Building schematics in kicad for now. This'll take a while since it's a fun project and only spare time goes in there. Want to get as much information as possible about what's obsolete in the schematics --> like the 8M Chipram jumper in the schematics.... Don't want to implement such things later in PCB Layout..... I'll give it my best! Attached Thumbnails

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28 February 2018, 12:32	#41
Chucky Registered User Join Date: Mar 2015 Location: Karlstad / Sweden Age: 52 Posts: 1,210	Serialport is important for DiagROM. (that will be very useful for debugging) but a db9 port. make it more modern. external floppy. well I can handle without it. do as AmyITX, they have used unused pins of the internal 34pin floppyconnector to handle more drives. then people can do a connector by themselved for external. if they want to.

28 February 2018, 13:37	#42
SnkBitten Amithlon Fanatic Join Date: Aug 2015 Location: Lexington, SC / US Posts: 781	I'd definitely keep Zorro slots on the board, I'd love a new(er) A4000 motherboard for ATX cases but I also have a lot of Zorro II/III cards that I don't want to give up. I'd want the A4000 experience.....Zorro boards, video slot, etc.. I agree with Chuck on changing as little as possible on your first design to make sure you have everything working, then start making your desired changes.

28 February 2018, 15:09	#43
elenachen Registered User Join Date: Feb 2018 Location: Nürnberg Posts: 97	Yes i agree with changing as little as possible. But there are things that can be easily left out, because they aren't connected on Standard. Does the A4000D need a Riser Board to work? Zorro is neat yes. But won't be unhappy to let that work be in queue for next Revision. A running version would be nice first. The 23 pin Video out is a pain in the ass too...... Which Pins aren't needed? I would opt for a D-Sub 15 instead if possible......but don't know if someone needs specific pins. Any suggestions?

28 February 2018, 15:15	#45
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	Amigakit does an adapter that allows the 23 way RGB to be converted to suit 15 way VGA. OK so it doesn't allow all modes but it does work to a fashion. Perhaps you could get some info on what pins go where with that device?

01 March 2018, 21:31	#54
idrougge Registered User Join Date: Sep 2007 Location: Stockholm Posts: 4,332	You should get a soldering iron, it might come in handy if you're going to build a computer. Oh, and you need a motherboard and a processor as well.

02 March 2018, 12:46	#56
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	Some nice equipment there !!

02 March 2018, 12:58	#57
Mick Registered User Join Date: Jan 2004 Location: Yorkshire Posts: 710	Best of luck and don't forget to keep us updated on progress!

02 March 2018, 20:05	#58
NorthWay Registered User Join Date: May 2013 Location: Grimstad / Norway Posts: 839	Why not have the connectors as internal headers with rows of pin pairs? Then you attach a flat cable to a break-out connector in one of the back slots. AFAIK that is how Amiga tower designs have been.

02 March 2018, 20:21	#60
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	@elenachen, how big is this new board of yours going to be? I ask this as an idea of converting existing PC cases to suit your design.

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