[Coco] 512K/1M/2M512M CoCo 3 Upgrades - Some Work Towards ThatGoal

[Little John (GIMEchip.com)]

Okay, so I've finished wire-wrapping the contraption. I am able to get the 
normal startup screen using the 3-chip simms, but when I try to execute the 
memory test, the computer goes into outer-space. So - the equations need 
work. I'm headed back to the drawing board... It almost works... but...
-John
----- Original Message ----- 
From: "Little John (GIMEchip.com)" <sales at gimechip.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, July 10, 2010 1:02 AM
Subject: Re: [Coco] 512K/1M/2M512M CoCo 3 Upgrades - Some Work Towards 
ThatGoal


>I have just finished wire-wrapping a standard 30 pin simm upgrade for the
> CoCo 3 and am using the SIMMs from my recently acquired Cloud-9 512K 
> upgrade
> to test it with. So far it is passing all of the tests from the 
> Performance
> Peripherals 512K Memory Test program. I am using this memory test program
> because it has a test specifically targeted at testing the memory's 
> ability
> to retain refresh. As I am now satisfied that this standard wire-wrapped
> 512K simm upgrade functions properly, I am about to add the 16V8 GAL to 
> the
> wire-wrapped mess that I now have. This will allow me to test whether or 
> not
> my refresh equations within the GAL are actually functioning. I will 
> replace
> the simms with the 3-chip kind and some odd 2-chip ones that I've found. 
> If
> this test passes, then I'll be able to produce the 2-Meg upgrade. I'll 
> post
> the results in a half hour or so. -John
> ----- Original Message ----- 
> From: "Little John (GIMEchip.com)" <sales at gimechip.com>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Friday, July 09, 2010 6:55 PM
> Subject: [Coco] 512K/1M/2M512M CoCo 3 Upgrades - Some Work Towards That 
> Goal
>
>
>>I have posted some of this here:
>>
>> http://www.coco3.com/community/2010/07/more-on-coco-3-memory-upgrades-512k1m2m-from-gimechip-com
>>
>> I am hoping fellow list members may be able to spot potential problems
>> with this design. I hope to get a functional 2-Meg upgrade ready soon, 
>> but
>> I've got to test these equations first. - Thanks All - John
>>
>> This is my proposed method of allowing the use of DRAM requiring a
>> 512-Cycle refresh in a CoCo 3 512K/1M/2M RAM Upgrade. If I have gotten
>> this correct, then it should be possible to make a 5-chip 512K RAM 
>> Upgrade
>> (four 256Kx4 DRAMs plus the GAL 16V8), or to use Any 30-Pin or 72-Pin
>> SIMMs in a CoCo 3 SIMM Upgrade. The Equations below should tell the story
>> if you examine them, or preferably, download the WinCUPL file for better
>> formatted text. Simply unzip the download and load the ".pld" file into
>> WinCUPL or a text editor. Let me know if you spot anything that seems as
>> if it will not work. Getting these equations working properly (I have yet
>> to test them) is the key to my proposed 2-Meg and 512-Meg Upgrades. Once
>> the memory board has been worked out, the DAT Board is child's play - you
>> could simply Copy DISTO's DAT Board, but my design uses a SRAM and
>> Multiplexers, etc. and also allows the added DAT bits to be read back
>> (they are write only in DISTO's 2-Megger). I have generat
>> ed PCB Layouts for both a 5-chip 512K and a 30-Pin SIMM 512K Upgrade
>> intended to use the PAL generated from these equations, however all of
>> this needs to be tested before I decide to order any boards - I'm hoping
>> you guys can let me know if this looks feasioble and correct.
>>
>> Thanks All - John
>> 512KAnySIMM_PLUS_512K-44256_PLD-Equations(GIMEchip.com)
>>
>>
>>
>>
>>
>> http://www.coco3.com/community/2010/07/more-on-coco-3-memory-upgrades-512k1m2m-from-gimechip-com
>>
>> --
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>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco
>
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