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Old 29 March 2018, 12:05   #341
SukkoPera
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I think the guys did that way so that you don't need to solder any jumpers if the default settings are OK for you. Thus you save time and components. And money, like 2 cents, LOL .

Problem is that it's not yet clear to me what the default settings are for. I guess they are fine for the most common case, which I reckon is a 512 KB expansion for an A500, but in all other cases you will need to cut the bridges, which I plainly hate.

I will try to come up with the table I mentioned, as soon as I complete my tests.

Anyone can provide the floppy/B52 images?
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Old 03 April 2018, 01:11   #342
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Hi, is this still available please?
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Old 03 April 2018, 04:45   #343
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Hi, is this still available please?
Just see post #2 and order your own straight from China. It's cheap & easy.
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Old 04 April 2018, 23:12   #344
SukkoPera
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So, I have finally tested personally all the possible configurations of this expansion I knew about. All configurations work very well and with full stability. Here's a report of how I set the various jumpers to achieve reliability with the different configurations:

Code:
Target				# Chips		EXRAM		RASU1	RASU2	RASU3	RASU4	XCAS

512k Slow (A500)		1		Closed		RAS1				All Closed
1M Chip (A500+)			2		Open*		RAS1	RAS0*			All Closed
512k Chip + 1.0/1.5 Slow	3/4		Closed		RAS1	RAS1*	RAS1	RAS1	All Open (Gary Adapter needed)

* Not default position
Now I understand perfectly why most of the jumpers have hardwired links on the board: that's because those settings are practically universal, there's hardly any need to change them in *any* scenario. The only jumper that might need to be set differently depending on the desired configuration is RASU2, and I guess that's why it's the only one that is NOT hardwired to any setting. Also EXRAM might need to be opened, but only in a single scenario, so the default setting covers most situations.

I just wish this had been stated more clearly, but I must admit this is a really good job!

I have one more question though: to achieve 1 MB chip, is a particular model of Fat Agnus required? Will it work on a stock Rev.5 mainboard with an 8371?

Last edited by SukkoPera; 04 April 2018 at 23:22.
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Old 05 April 2018, 02:15   #345
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Originally Posted by SukkoPera View Post
I have one more question though: to achieve 1 MB chip, is a particular model of Fat Agnus required? Will it work on a stock Rev.5 mainboard with an 8371?

You need the 8372 Agnus to have more than 512k chip RAM.
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Old 05 April 2018, 07:54   #346
SukkoPera
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That's what I thought, too. Thanks!

Se finally here's a picture of my job:


Last edited by SukkoPera; 05 April 2018 at 08:05.
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Old 05 April 2018, 13:06   #347
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Also EXRAM might need to be opened, but only in a single scenario, so the default setting covers most situations.?
Even EXRAM is "don't care" on a A500+ because it's not connected on the motherboard!

I looked for the B52/floppy BMP files but couldn't find them. Maybe I'll check another computer later.

Nice to see photos of finished boards.
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Old 05 April 2018, 18:46   #348
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That's keirf's systest: https://github.com/keirf/Amiga-Stuff
You can download a bootable ADF there, it's good stuff for h/w testing.
Thanks a lot
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Old 06 April 2018, 11:22   #349
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Hey guys,

you got a nice project here!

I got some problems to get my board working with 6a Amiga.
So, first of all, can I use these:



And if yes, hol do I have to set the jumper?

For the moment I‘m a little bit confused and not sure where to look at.
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Old 06 April 2018, 11:35   #350
SukkoPera
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Just look at the table I posted a few days ago.

Nice soldering, BTW!
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Old 06 April 2018, 11:49   #351
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Ok, thank you but non of these positions had been working on my board.

I‘m afraid of using wrong memory on it.



By setting other jumper positions just getting white or green screen.
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Old 06 April 2018, 11:53   #352
SukkoPera
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I guess you're using the Gary adapter. Just link all RAS signals to RAS1 (did you remove the hardwired connections? I don't see them on your board), close EXRAM ENABLE and cut/open all the XCAS signals.

Also remember you have to cut JP2 on the mainboard and connect the center pad to the Gary adapter.

If it doesn't work, remove the Gary Adapter, solder JP2 center pad to bottom pad and test the expansion as a simple 512k.
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Old 06 April 2018, 11:57   #353
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Yes, I do use the Gary Adapter. Do I have to do something spezial on the expansion to use it as 512k? I soldered 4x RAM on it.
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Old 06 April 2018, 12:08   #354
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Not really, just link RASU1 to RAS1 and close EXRAM ENABLE. You can leave the other RASUx signals linked as well, if you don't have jumpers on them.

But make sure to remove the Gary Adapter, as the fault might lie in it.
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Old 06 April 2018, 18:10   #355
Clamshell
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Ok, thanks for your help. Now I checked that. It is the RAM!

Kicked them out


And soldered others onto the Board


But, every single one for its own is working too.


And now:


Working
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Old 06 April 2018, 21:25   #356
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Ah, nice work clamshell. I'm glad it's working now after some trouble
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Old 07 April 2018, 16:58   #357
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Yeah, thank you Katarakt, and thank you for the Parts!

Well, who guess that the RAMs do act like that.
I love that Project! How cheap and easy it is to get 1mb Chipram!

Thank you to all who made that possible!
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Old 25 April 2018, 21:25   #358
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Question: Is exram jumper and switch jumper the same ?
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Old 25 April 2018, 21:53   #359
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Yes.
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Old 25 April 2018, 22:42   #360
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Thanks!
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