*SOLD OUT* 32k RAM expansions for the VIC-20 - 25$ each

eslapion · Post by **eslapion** » Tue Mar 26, 2013 5:26 am

sjgray wrote:Well, most VIC and C64 cartridges use masked 8K roms which are definitely NOT pin compatible with most 8K EPROMS.

The 2364 series of ROM used in Commodore 8 bit computers are 100% pin compatible with the Motorola series MCM68766 and MCM68764 EPROMs but that remains irrelevant since the UE was designed for 16k and 32k (EP)ROMs.

So these are fairly large compared to normal carts. I was assuming perhaps one 8K ROM or EPROM would fit there.

The point of having this type of (EP)ROMs on the UE is that you can have multiple carts (up to 8 ) in a single expander along with the extra RAM.

eslapion wrote:If you know how the VIC memory map works, no documentation should be necessary.
Like I said.. I don't really.

Then you would have a very hard time using these switches even if somebody else added them for you on your expander.

This pdf explains how it works:
http://retroinformatica.altervista.org/vic20memory.pdf

A look at the VIC-20 Programmer's reference guide is strongly suggested.

The switches toggle Block 3 and block 5 between RAM and ROM. For example, Programmer'S Aid was originally designed for Block 3, Super Expander only works in Block 5. VICMON uses the upper half of Block 3 and can be combined with Programmer's Aid. Basic V4 uses the lower half of Block 5 and can be combined with a special Block 5 ($B000 ) version of VICMON.

eslapion wrote:The board was specifically designed to accept a 28 pin DIP 0.6" wide socket. A socket is recommended if you eventually want to change the content of your (EP)ROM without the need to desolder.
Sure, a socket is nice. I was thinking more of clearance... The board is really tight to the case.

If you're worried the height of the socket might cause a conflict with the space available in your casing then low profile can be used. They are a bit more expensive (about 2$) but they occupy virtually no space.

sjgray · Post by **sjgray** » Tue Mar 26, 2013 8:11 am

I was hoping for a manual for the UE. Perhaps now that your run is finished you could also publish the schematics?

Don't get me wrong, I like the UE and the rom option seems very handy and more flexible than I thought it would be. Without documentation those features are un-accessable. You can't assume you or Denial will be around forever...

Steve

eslapion · Post by **eslapion** » Tue Mar 26, 2013 1:54 pm

sjgray wrote:I was hoping for a manual for the UE.

There is a manual for the Ultimate Expander. It used to be online but there is a pdf version. Just PM me your e-mail addres and I will send it to you.

Perhaps now that your run is finished you could also publish the schematics?

Perhaps I was a bit naive but since there is no programmable logic such as PALs, GALs or CPLDs on the UE, you can just follow the traces and there you have it.

Don't get me wrong, I like the UE and the rom option seems very handy and more flexible than I thought it would be. Without documentation those features are un-accessable. You can't assume you or Denial will be around forever...

I did not assume I or Denial would be around forever. What I did assume, perhaps with a bit of wishful thinking, is that anyone enclined to study the pinouts of standard (EP)ROMs along with a bit of knowledge of how the VIC addresses external memory would be able to figure it out by themselves.

Example:
Take a look at pin 27 of the (EP)ROM footprint. Where does it go? It leads to the center pin of the rightmost switch. Itself, is tied to the ground on the left pin and to the 5V source via a resistor on the right. Pin 27 on a 27256 is A14 which means the switch toggles between the lower and upper half of the content of a 27256.

On a 27128, the same pin is !P so if you install a 27128 on the UE, instead of putting a switch, you just permanently tie this line to 5V with a jumper.

If you follow the BLK3 line from the VIC cart port you'll see it ends up to one of the DPDT switch and its output either leads to the RAM decode LS08 or to pin 26 of the (EP)ROM footprint. This means if you use a 27128 then the lower half will be presented to Block 3 when ROM is selected for that VIC's memory area. The upper half is available to Block 5 when the corresponding DPDT switch is set to ROM.

If you use a 27256 then imagine it divided in 4 sections of 8k. The odd areas will be available to Block 3 when selected and the even areas will be available to Block 5. The lower ones available when the rightmost switch is set to the left, the upper ones available when the same switch is set to the right.

Alan · Post by **Alan** » Wed Mar 27, 2013 6:47 pm

Hi there. I've posted the original instruction sheet for the Ultimate Expander on my blog at CommodoreServer.com.

Read it HERE

Post by **joshuadenmark** » Thu Mar 28, 2013 1:51 am

Alan wrote:Hi there. I've posted the original instruction sheet for the Ultimate Expander on my blog at CommodoreServer.com.

Read it HERE

Link error

Alan · Post by **Alan** » Thu Mar 28, 2013 7:53 am

Oops

Working now.

eslapion · Post by **eslapion** » Thu Mar 28, 2013 10:34 am

Alan wrote:Hi there. I've posted the original instruction sheet for the Ultimate Expander on my blog at CommodoreServer.com.

Read it HERE

Great work Alan.

Thanks again for this nice work.

akator · Post by **akator** » Sat Apr 06, 2013 3:12 pm

Thank you so much for the excellent Ultimate Expander.

I recently acquired a Cardboard 3s (with DIP settings for each of the 3 slots). Is it possible to have both the 3K Super Expander and the Ultimate Expander plugged in and usable at the same time, or do I need to keep swapping them out when I want to run 3K programs?

buzbard · Post by **buzbard** » Sat Apr 06, 2013 7:28 pm

The Ultimate Expander fills all 4 of the 8k blocks with RAM.

The 3k Super Expander fills the 3 1k RAM blocks that the UE doesn't cover but it also adds a ROM in block 5($A000) which conflicts with the block 5 RAM that the UE supplies.

You'll need a way to either disable the Super Expander's ROM or a way to "switch off" the Ultimate Expander's block 5 RAM.

akator · Post by **akator** » Sat Apr 06, 2013 9:30 pm

buzbard wrote:The Ultimate Expander fills all 4 of the 8k blocks with RAM.

The 3k Super Expander fills the 3 1k RAM blocks that the UE doesn't cover but it also adds a ROM in block 5($A000) which conflicts with the block 5 RAM that the UE supplies.

You'll need a way to either disable the Super Expander's ROM or a way to "switch off" the Ultimate Expander's block 5 RAM.

Thanks for the response, I suspected that was the case

vicist · Post by **vicist** » Sun Apr 07, 2013 4:03 pm

You can switch off the rom part of the Super Expander with SYS 64850.

Turn it back on with SYS 41031.

Mike · Post by **Mike** » Sun Apr 07, 2013 4:47 pm

vicist wrote:You can switch off the rom part of the Super Expander with SYS 64850.

If anything, that SYS will just disable the BASIC extension of Super Expander by calling (part of) the standard reset routine in the KERNAL. The ROM of SE *still* remains mapped into BLK5 and will clash with expansion RAM that occupies the same range.

vicist · Post by **vicist** » Sun Apr 07, 2013 4:59 pm

Thanks for that info Mike.

A valuable technical detail from you as always

eslapion · Post by **eslapion** » Mon Apr 08, 2013 4:16 pm

akator wrote:Thank you so much for the excellent Ultimate Expander.

I recently acquired a Cardboard 3s (with DIP settings for each of the 3 slots). Is it possible to have both the 3K Super Expander and the Ultimate Expander plugged in and usable at the same time, or do I need to keep swapping them out when I want to run 3K programs?

Use the DIP settings to disable BLK5 on the Ultimate expander and you'll have a super expander with 28k of RAM.

The Super Expander DOES support 8k or more of ram expansion.

Mike · Post by **Mike** » Tue Apr 09, 2013 12:31 pm

eslapion wrote:The Super Expander DOES support 8k or more of ram expansion.

Yes indeed it does - just for general info: when a graphics screen is activated the first time, SE normally 'lowers the roof' available for the BASIC program and variables down to $0FFF (minus some extra for function key definitions). With +8K RAM or more, the BASIC start is set to $2001 instead, and the program is copied to the higher address, clearing all variables underway.

However, from what I gathered, akator seemed to be especially interested in RAM in BLK5 for softloading cartridge images - but as BLK5 is already occupied with the SE ROM, this is not possible ... unless you open the Super Expander and remove the ROM, thus reverting the cartridge to a standard +3K RAM expansion, but I think this is somehow wasteful. One could still softload the original ROM though, when RAM was available in BLK5.

A standard +3K RAM expansion surely is found on eBay for 5$ or less.