Memory upgrade for A1200

[fafler]

I just got a A1200 and it needs more memory. I don´t want to pay a lot of money for a accelerator board if i can avoid it. 020@14 is enough for occasionally playing WHDLoad games. Whats the easiest way to upgrade the memory? Piggyback 4 512 kb DRAM modules on the existing ones and program a PAL to map them as FastRAM? A PCMCIA card? Something else?

[swift240]

A cheap memory board from eBay will do it.

You will get 8meg of Fastram from one of those.
But make sure it dont conflict with the PCMCIA part.

Mike.

[meega]

A cheap memory board almost certainly will conflict with PCMCIA unless it has 4MB or less on it. On the plus side, even that will pretty much double the speed of your machine, no extra processor needed.

[swift240]

I used a memory board some years ago on the 1200 I got 8 meg of Fastram and this did not conflict with the PCMCIA port, for the life of me I cant remember the name of the board now.


Thinking.............

[swift240]

Finished thinking..........

Ahhhh yes I had a RAM 8 was it? something like that.... any way yes you are correct I got 4 meg Fast ram, it was the Apollo Lite that gave me 8 meg Fast ram.

Ahhhh yes my first every Amiga 1200 add on.



Mike.  :crazy:  :crazy:

[Xamiche]

I'm selling a Microbotics 8MB RAM board on eBay at the moment. Not sure where in the world you are though. It might be too far for you.

I believe there's a fix for the PCMCIA problem when using an expansion. I'll see if I can track down what needs to be done.

Edit: I didn't make this. It's from Aminet. I have never done this modification so I cannot tell you if it works, but I heard of others doing it. I believe AmiKit even has a product that will fix the PCMCIA reset issue with a socket that clips over the Gayle chip.

The A1200 (and A600?) PCMCIA-port has a bug which causes some PCMCIA-cards
(especially ethernet-cards) not to work after hardreset until you remove
the card and insert it again while power is on.

It seems as if the A1200 is not generating any reset-signal for the PCMCIA-
port. The problem is easily solved by soldering a 10uF capacitor between
CC_RESET and and Vcc. The CC_RESET is active high. The cathode (-) of the
capacitor should be at CC_RESET.

CC_RESET can be found on pin 5 of Gayle (U5) and Vcc on R715A (the end which
is near Gayle).

WARNING!
Although this is a very simple thing to solder please consult a professional
if you are not good at soldering. I take no responsibility for any damages
caused by doing anything described in this file.


Thanks to
---------
Filip Kopec   for making the A1200info series.

Author
------
Pontus Fuchs
email: pontus.fuchs@bluechoice.se
homepage: http://foo.birdnet.se/~pf/

[Lemmink]

I believe there's a fix for the PCMCIA problem when using an expansion. I'll see if I can track down what needs to be done.

You will only need to do a little redesign of the memboard of your choice by adding an own memmory controller.....
Seriously, the plain 8 MB FastRAM boards use the Amiga autoconfig to add the memory to the system. Autoconfig will place the RAM into the 8 MB ZorroII window. That is the reason why those boards are limited to 8 MB.

What you remember is the fix for the PCMCIA reset bug. Without that fix you will have to reinsert a PCMCIA networkcard after every reset to be recognized. There is a hardware and a software patch for this.

[meega]

The A1200 uses 4MB of 24-bit Autoconfig address space for PCMCIA, and 8MB expansion cards in the trapdoor overlap that space unless there is some extra logic somewhere to deal with the issue. Using 4MB on the card does not cause that conflict.

[Xamiche]

Ahh, I see.

I'm not sure if my Microbotics board conflicts in the way that you've mentioned. I had no trouble with it, but then I never used the PCMCIA slot.