A1200 DKB 1202 Question

TheCorfiot

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Having recently aquired a DKB1202 from our good friend arnljot, I have a queestion for those who may be quite familiar with the card.

My question stems from the fact that I do not have any suitable single sided 4MB 72pin SIMMS.
Our good friend Zetr0 has sent me some SIMMS but alas they are double sided 4MB modules and as you will all be aware these cannot be fitted due to the proximity of the SIMM sockets interfering with the RAM chips on the backside of the SIMMS (same as A4000 FastRAM sockets).

Sooooooo, in desparation I plugged in a solitary 8MB module into the top socket & set the jumpers to 8MB & lo & behold it seems to work & provide 8MB of FASTRAM using just the single socket.

Now this is the head scratching bit.. I thought these sockets could only map a max of 4MB each......

WHDLoad Games Seem to load & work fine & I watch the memcounter go down....

Can anyone help explain this for me, my thoughts are that this "ghostly" 4MB of RAM is not really there but the A1200 thinks it is writing to the RAM because the card's FPGA has configured it as being present supposedly....

Cheers all

TC :)
 

Zetr0

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My friend Tiago from Classic Amiga, had this card.

It has some problems as it couldn't boot, after some diagnosing it turned out to be a dead FPU holding up boot.

in the process I tested the Ram etc, and the memory is added by software NOT tested and added by the hardware -

The memory will go down as expected however when it falls below the 4MB (from 8MB) thats when it start over-writing itself again.

I have sent you another parcel my friend, in it is a whole bunch of 4MB sims, both single and double sided.

=D
 

TheCorfiot

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Cheers for the info Zeets (y)

So it's a bit like the ole 4GB IDE limitation in that it returns to the beginning & overwrites itself..:LOL:

Thanks for the extra SIMMS my friend :bowdown:
It wouldn't hold me back from testing Juvvy's Mobo as it can function with just chipRAM installed anyway...
Speaking of which the battery corrosion is quite nasty under a magnifying Glass :blink:

I'll give you a bell tomorrow mate (y)

TC :D
 

Zetr0

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@TC


I have to admit it certianly wasn't pretty my friend, although I did manage to buzz out all the effected tracks and their still viable.... well.... they were...
 

TheCorfiot

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@TC


I have to admit it certianly wasn't pretty my friend, although I did manage to buzz out all the effected tracks and their still viable.... well.... they were...


Cheers mate

If they test good for you, then they test good for me...
I'll leave that area for last then... (y)

PS... Got the 030 & SIMMS today...
And they are all single sided...........:arms
I'll post the others back to you soon, hopefully with some hardware too ;)

Best Wishes
TC :)
 
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