VIC-20 32K RAM Upgrade

[bluejay]

I thought of building a 32k upgrade for my VIC-20 since the ones that are for sale are ridiculously expensive and comes with other junk I don't need(COUGHCOUGHPENULTIMATECOUGHCOUGH).

While I was searching around, I came across this: http://www.zimmers.net/anonftp/pub/cbm/documents/projects/memory/vic20/32kB.html

 

I have a lot of questions.

First and foremost, isn't the 62256 a 32Kx8 256k SRAM chip? Can it be used as a normal 32k chip?

Also, the author mentions that he has it hooked up to a veroboard inside his VIC-20. That would require soldering the connections directly to the solder pads of the cartridge port, correct?

Lastly, would it be costly to have a PCB and a case made for this? Or is it easy enough to mount it internally?

[brain]

I question your statement that there are not 32K options at economical prices, but there's a few projects online to build your own:

 

https://github.com/dikdom/VIC-20-RAM-ROM-Expansion

 

I know there's a design that fits completely in the space between the edge connector and the edge of the case, but I can't find the list.

 

I know I also designed VICMem for some folks at ECCC/VCF-MS a few years back, and cna put the project files up.

 

[bluejay]

35 minutes ago, brain said:

I question your statement that there are not 32K options at economical prices, but there's a few projects online to build your own:

 

https://github.com/dikdom/VIC-20-RAM-ROM-Expansion

 

I know there's a design that fits completely in the space between the edge connector and the edge of the case, but I can't find the list.

 

I know I also designed VICMem for some folks at ECCC/VCF-MS a few years back, and cna put the project files up.

 

I mean, a small board that goes in the cartridge port would be rather inconvenient as the limited grip and the stiffness of the VIC-20's cart slot would combine into a mix of frustration and hate every time I want to play a cartridge game. But thanks for the project link!

[dragos]

You could get a port expander and switch it off when you don't want to use it.  Here is my project, if you change your mind:

 

http://blog.victwenty.org/2016/11/late-but-long-winded-product-update.html

 

I sell them for $30....

 

 

[bluejay]

Thanks for the replies, but I'm really not interested in preassembled stuff unless they're, like, super cheap. I'd like to put one together myself.

[bluejay]

Also, is it terribly complicated to modify a 32k expansion to accomodate 3k extra to make it 35k(I wanna play some DOOM!)

[dragos]

I'll sell you a pcb, bit you are on you are on your own for support...

[bluejay]

Quote

...but I'm really not interested in preassembled stuff unless they're, like, super cheap. I'd like to put one together myself.

...as in I'd like to have one made from the ground up by myself. It might be only slightly cheaper than your finished product, and maybe of lower quality, but I think it'll pre pretty fun. Besides, if I were to make it myself, I can customize it to however I want, such as putting actual switches instead of jumpers.(I'd have preferred switches over your "features"...)

Edited October 13, 2020 by bluejay

[carlsson]

Hm, it appears the supply for inexpensive VIC-20 RAM expansions has dried up in the last two years. Here are two from Italy, which unfortunately means some shipping costs on top of the price:

 

37K expansion at 20 Euros

35K expansion at 25 Euros

 

Sure, your DIY might be much cheaper than so, in particular if you get a PCB to work from and you know what you're doing.

[dragos]

No pleasing this guy... 

 

You should have clearly stated you wanted someone to handhold you through building your own, internal expansion.  Based on your questions, it seems you are probably not capable, but who knows.(or at this point in the thread, cares)

 

FYI, this is really not the place to post real C= questions, many much better options, clearly you have done your research ....

[bluejay]

1 minute ago, dragos said:

No pleasing this guy... 

 

You should have clearly stated you wanted someone to handhold you through building your own, internal expansion.  Based on your questions, it seems you are probably not capable, but who knows.(or at this point in the thread, cares)

 

FYI, this is really not the place to post real C= questions, many much better options, clearly you have done your research ....

That's why I'm trying to learn. I don't know much about the project I'm trying to do when I'm beginning; I learn more as I go. I'm looking through datasheets, and when I get to a part where I don't understand, I ask here, and most of the time people here with knowledge in the area responds and I continue with my project. I'm not asking anyone to guide me throughout the entire process.

 

I know there are better places to ask Commodore related questions, but I guess I just feel more comfortable asking here. Besides, I've yet to find a forum that has a better user interface than AtariAge.

 

I apologize if I'm annoying anyone here. I simply find that asking questions here helps me understand the stuff that I don't exactly get from datasheets and manuals. If you don't want to respond to whatever I'm asking, I won't hate you.