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php1260 32K x8 mod as sidecar or internal?


haxtor

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I purchaced a 32k x8 peb memory card today cheep with the intnet to mod it :)

 

My plan: build an adapter to use the card as a sidecar or mod the card to be installed inside the main system.

 

I have seen this done before with a disk card but never with a memory card.

 

http://www.avjd51.dsl.pipex.com/ti/images/disk_system.jpg

 

Has anyone attempted this before?

 

Looking at the schematic, this shouldn't be too hard should it?

 

http://www.mainbyte.com/ti99/schematic/mem_82_2.jpg

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It depends on your end goal. If you just want 32K in the console, I think a single modern memory chip with a simple programmable logic device (PAL or CPLD) would be the way to go. The use of a CPLD puts all the decoding and select logic into a single device, so you get a simple two-chip solution. However, if you want to keep the original "retro" look/feel of using original hardware, then hack away.

 

The external nature of the first picture you linked looks like a failure waiting to happen with the memory card propped up and such. If you are going to keep the bulk of the original RAM card plus full-height floppy drives, IMO just keep things inside the PEB. Moving to a "side car" does not give you anything unless you end up with a configuration smaller than the PEB.

Edited by matthew180
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I purchaced a 32k x8 peb memory card today cheep with the intnet to mod it :)

 

My plan: build an adapter to use the card as a sidecar or mod the card to be installed inside the main system.

 

I have seen this done before with a disk card but never with a memory card.

 

http://www.avjd51.ds...disk_system.jpg

 

Has anyone attempted this before?

 

Looking at the schematic, this shouldn't be too hard should it?

 

http://www.mainbyte....ic/mem_82_2.jpg

 

Richard Bell sells internal 32K RAM kits that sit on the 16bit bus, and provide at least a 30% speed boost to the console. It's a little tricky to install because some chips have to be removed from the motherboard, but it's definitely feasible. He can be contacted at swim4home@facebook.com

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Well for one issue, I don't own a peb yet.

 

Another issue is that I cant find the schematic for that 32K 16 bit bus upgrade.

 

I am really interested in learning how the various logic and bus chips work.

 

Maybe I can work out a nice way to test out peb cards and do some experiments with them, I just need a little guidance in the right dirrection.

 

I would have to say a goal I have is to be abble to use the peb ram card along with my speach sidecar.

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SAMS is really the only way any advanced programming can happen on the TI99/4A as 32K is really so small to do much of anything. I work in GPL but that also requires a expanded memory of GRAM.

Also RAMDISK is so much better then DISK for many reasons as an example is running a compiler is 6 times faster on a RAMDISK. 5 minutes vs 35 minutes for the same file to be compiled.

A dream system is SAMS, (GRAM CARD) PGRAM, 32K (High speed version), RAMDISK, HARD DRIVE CARD and 80 Column card.

When I had this set up there was really nothing my TI could not do much more quickly.

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If you don't mind not getting the 16-bit boost, you can put 32k inside the console with only 2 ICs - the 32k SRAM and an AND gate. This will be far more reliable and draw far less power than trying to get the PEB card to work. The PEB card uses DRAM and has additional power requirements. My document on this mod is here: http://www.harmlesslion.com/text/TI%2032k%20Mod.pdf

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Another possibility is to do the so-called "matchbox" expansion. This worked fine, though like Tursi's, it doesn't get the speed increase of the more complex 16 bit expansion. It uses 4-8K static ram chips piggybacked and plugged into a socket. The socket has a bunch of wires which connect to the back of the cartridge port. I imagine that it could be done with a single 32K static ram chip. Here's more info:

ftp://whtech.com/user%20groups/Brisbane%20Australia/TIBUG-1985-06.pdf

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