A600 8Mb fast expansion

[1NOM155]

nice work.

but one question, instead of welding the ram, cant be more easy use a SIMM sockets? if it possible.

[1NOM155]

sorry for double post.

alert:

the button "Cancel Post" doesn't work

[1NOM155]

by rkauer on 2007/12/20 22:27:03

Doing this you'll have more complexity in the board layout.

I simply prefer the SIMM header to solder any bank of memory I choose. Even if the SIMM fails, it's easy to swap for other bank (although it have to unsolder the bad first).

i agree

[1NOM155]

Crumb wrote:
@countzero

I wonder if it would be possible to hack card.resource to map this area instead of 200000-9FFFFF

that would be a good idea...



@thread

Do you remember 72c simm sockets are very hard to find now?... And desoldering a 72c socket is a huge job... IMHO it's easier to desolder the 4 chips of a simm than desoldering a 72c simm...

no way, in POR, you can find that in some stores.

[1NOM155]

lordv wrote:
Currently I'm fighting again with some long-term socket contact stability problems. DRAM chips seem to be OK since I've used nice "slow slew rate" option for altera outputs =)
 
The main problem besides socket contatability, from my point of view, is indeed pcmcia 4 Mb space. So now my plans are to redesign board. It will probably have epm3064 in tqfp100 with no extra MUXes and some jumpers to select none/4/8 Mb size. SIMM sockets are indeed very hard to find except for desoldeting them from old PCs (and more, they should be laying and not standing as in majority of PCs). I don't think this way is acceptable.

what about of U2J1/U3J1 sockets??

[1NOM155]

lordv wrote:
Currently I'm planning sell some fully assembled old version PCBs (only 3 of them) to start making new ones. Unfortunately old PCBs will be sold to local people who sent me a lot of SIMMs to desolder. =) Anyway, the unpopulated PCBs of this design itself can still be ordered for smth 8$ each (I won't order a huge bunch of them, but little quantities will be priced like that).

Next version will have TQFP100 epm3064 CPLD, jumper for 0-4-8 Mb selection and some elegant (imho little piece of PCB under main PCB containing SMD 68pin PLCC socket, hope this will solve contactibility problems =)

Oh, as well, I should put some info concerning this old design... probably within few days =)

PS: Happy Christmas for those of you, who сelebrated it yesterday =)))

why a jumper for 0 - memory? and can be possible to use SIMS or ram sockets?

[1NOM155]

lordv wrote:
The first run of 6 PCBs for old design is ordered, will arrive soon. Also 4 of new (2008 y) boards ordered, I'll assemble one as soon as they arrive.

PM sent

[1NOM155]

can this be apply to A500, with full 8mb?

[1NOM155]

rkauer wrote:

1NOM155 wrote:
can this be apply to A500, with full 8mb?

 Of course it can! But you have to modify the 68000 connector to use a DIL socket (wired, perhaps?).

 Or make a new designed board.

 But the schematics will not change a single bit.

and can i use the full 8mb ram, without lose anything? A500 don't have PCMCIA, but i wont to use a mod for IDE.

[1NOM155]

In the A500 and A600 uses a MC68K, on ACD32 uses an MC68EC020, the connections points aren't the same.

[1NOM155]

lordv wrote:
Colani1200:

Could you explain that a little further? How will the new version be connected?

The same way, but the board will be two level, so that no need to tilt the socket when soldering it, also better cooling of CPU and chipset beneath the board. It looks like this: http://dlcorp.ucoz.ru/_fr/1/3207130.jpg http://dlcorp.ucoz.ru/_fr/1/3208886.jpg


Regarding A500, it probably should work, but I haven't A500 to check. Probably new version would be easier to adapt for A500.

lordv, i have 3 A500, i can test on one

the new PCB, its great, because "on future" can be use on every Amigas with 68K CPU, just have to change CPU connector.

[1NOM155]

yes i know, lol i don't route correctly, eheh, when i said MC68K, i may say only the 68000 version.
This can be applied to A1000, 2000 & variants, 500, 600, CDTV?

Lordv, another thing, this expansion, can take any advantaged of the A600 trapdoor? Or the trapdoor can be only used for 1mb chip ram?

[1NOM155]

yssing wrote:
Probably a silly question, but could this be used with the MiniMig?

yssing, i don't fink your question silly, but reasonably, maybe LordV can put that working.

[1NOM155]

does anyone know the memory type its used in A500 512kb expansion ram?

see my expansion memory ram:



i know its bad, but clean it, i will put new photos soon, but i need some help to rebuild a new board and maybe make a new ones.