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-   -   GVP 64 pin RAM (http://eab.abime.net/showthread.php?t=35729)

skote 28 March 2008 18:24

GVP 64 pin RAM
So... I've recently (re)bought myself and A1200 and have tricked it up. I am very pleased with it, and also Bloodwych's Workbench installer :great. I've picked up a GVP 1230+ accelerator with with an 030 onboard running at 40MHz. I wanted something that would take 72 pin SIMMs and had an RTC, but got sick of waiting for one to turn up on FleaBay and go for silly money. I've been trawling the InterWebNetDotCom for some GVP style RAM but I have found absolutely none...... My questions to you wise people are therefore:

1) Will RAM made for a Mac IIFX (also 64 pin) slot into the board and work OK?
2) Does anybody make a 64 to 72 pin SIMM adapter so I can use more common RAM?
3) Why the hell did GVP decide on a rare RAM configuration anyway?


coze 28 March 2008 18:30

2)you have to make one yourself
3)to be able to sell them at stupid prices without competition from cheap imitators ?

skote 12 April 2008 23:50

Thanks for the reply. I just got back from being away. Are you sure that the 64-pin Mac RAM does not work....? I mean.... the chips will have been made by a third party and will therefore be some "standard" voltage, so why wouldn't a 64-pin Mac SIMM work? :confused Has anybody tried it?

coze 13 April 2008 06:33

I tried it. It doesn't work because probably pinout is completely different. There's no standard on 64 pin SIMMs, so GVP and apple adopting the same pinout would be a really small probability anyway.

Zetr0 13 April 2008 13:56


I looked into building a Adapter board, but the memory controllers for both type are differnet, so its not just differently arranged signals, there are different signals to boot.

The linkie Coze has provided, is the only realy method at the moment for said hackery, infact i was going to make and Adapter board that went from gvp64 to standard 72pin edo/fpm

there were a few of problems
  • It would need to be manufactured due to the pcb size required (not cheap)
  • It would show compatibility issues with some 8MB (depending on how there matrix was arranged)
  • 16MB / 32MB SIMMS would not work at all.
  • The biggest problem would be that the Adapter would not fit insidea a basic A1200 case.

I even thought well hey, just build a controller for the missing circuit, but GVP have what can only be considered archaic in memory controll

so yes,.... get hacking....

coze 13 April 2008 16:00

I think instead of an adapter board, building the GVP 64pin SIMM board PCB would be more trouble free. You'ld then need to desolder chips on a 16 mb SIMM and solder on the new board.

Of course this would require lots of time and money, cause you probably wouldn't get the PCB in the right form factor in the first prototypes ...

Zetr0 13 April 2008 17:05


would you have a proper pinout for the GVP 8MB sticks ? or some nice hi-res photo's back and front ?

coze 13 April 2008 17:30

I have some pinouts I made myself but they're a mess (and you may already have them :)) Also, there are no 8mb GVP sticks. They only come in flavours of 4 and 16. Almost all GVP stuff I had had jumpers to set 4 and 16 mb sticks, so you can't mix-match them and there's no auto recognition, so it shouldn't be too complex really. Also the GVP hack at Aminet is only re-routing of signals (no logic involved) so it should be possible. There was only one issue of OE or something to be solved, and the guy had to connect it to Parity line or something, can't remember right now ...

skote 22 April 2008 20:43

Softhut are selling 4MB SIMMS at the moment.....:bowdown

Zetr0 22 April 2008 21:26

dare i ask how much, and if they actually respond LOL.

rkauer 23 April 2008 05:37


Originally Posted by Zetr0 (Post 409329)
dare i ask how much, and if they actually respond LOL.

A leg and an internal organ, I dare to bet.:sad

The problem on the aminet hack is only the special SIMM socket (lacks in any serious PCB program). But I think it is only a matter of making a 4-layer mini-board and solder (yes, solder!) the regular 72-pin SIMM on it to achieve a nice GVP SIMM "emulator"...:crazy

skote 29 April 2008 19:34

Well... I got a single 4MB SIMM for £21 including delivery from Softhut this morning. It took one week after I paid with PayPal for it to arrive. It was well packed and I've been offered a $5 discount off a future purchase. Now I have a whopping 8MB of FastRAM. Je suis le Papa? :lol Of course I would have liked to get a pair of 16MB SIMMs, but they guy said he couldn't get me any, and in any case I suspect they would have been mega money. A good experience I reckon.

Zetr0 29 April 2008 20:46

well played Skote,

i am truly pleased for you!

alas i have never had any luck with Software Hut...

..... so Skote...... whats your lottery numbers ;) :great

skote 29 April 2008 23:26

Um.. it's the same as my PIN... 1,2,3,4,...... ;)

Zetr0 29 April 2008 23:58


Originally Posted by skote (Post 410670)
Um.. it's the same as my PIN... 1,2,3,4,...... ;)

hmmm :blased i sense a ruse.......

skote 04 May 2008 16:13

I have noticed something now that I have 10MB in total on the 1200. The boot time is MUCH reduced. Is this because the Kickstart is now being loaded into FastRAM when I boot? The reason I ask is that there is a command to do this in my startup sequence and I used to get an error message saying that there wasn't enough RAM when I only had 6MB...?

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