memory maker 64k

leof · Post by **leof** » Mon Feb 13, 2012 4:04 pm

It's here: http://vic20.de/html/64k_karten.html.
The lower one.

tokra · Post by **tokra** » Mon Feb 13, 2012 4:24 pm

Well, I recently found the manual for the 32K-version, which shows already that things are rather complicated with the dip switches (off means RAM on for some areas...). Anyway, this could be a starting point. Would love to find the manual for the 64K-version as well

http://www.tokra.de/vic/memmaker32k.png

leof · Post by **leof** » Tue Feb 14, 2012 1:18 am

Thanks a lot for this manual. Now we have to hunt for the 64k version.

leof · Post by **leof** » Tue Feb 14, 2012 2:07 am

On the internet I can find two 64k RAM expansions for the VIC-20:
from Century and from APS.
According to this snippet out of a Transactor magazine it is not the APS we are looking for:

nbla000 · Post by **nbla000** » Tue Feb 14, 2012 11:39 am

tokra wrote:Well, I recently found the manual for the 32K-version, which shows already that things are rather complicated with the dip switches (off means RAM on for some areas...). Anyway, this could be a starting point. Would love to find the manual for the 64K-version as well

http://www.tokra.de/vic/memmaker32k.png

Wow, thank you, it could be very useful but someone may translate it in English ?

leof · Post by **leof** » Tue Feb 14, 2012 2:08 pm

In English (the table on the right is self explanatory):
Installation:
-----------------
Connect the 32k RAM module to the expansion port of the VIC-20 (right side). Set switch S2, S3, S5 and S6 to “ON

tokra · Post by **tokra** » Tue Feb 14, 2012 3:06 pm

leof wrote:If S4=OFF, S5=OFF and S6=ON then 0400-0FFF will have the same data as the memory area A400-AFFF.

I believe this to be a typo in the original manual since S6 control $2000-$3fff. It probably should read:

If S4=OFF, S5=OFF and S1=ON then 0400-0FFF will have the same data as the memory area A400-AFFF.

This would make a lot more sense, since it was common for those 32K expansions to double-use the 3K-RAM area with an 8K-block. Sadly this way you cannot get a true 35K-expansion like you need for VIC-DOOM. You still need a FinalExpansion3 or MegaCart for that (or if you're oldskool a slot expander with an extra 3K-expansion...)

nbla000 · Post by **nbla000** » Wed Feb 15, 2012 11:13 am

Thank you very much for your translation.

tokra wrote:Sadly this way you cannot get a true 35K-expansion like you need for VIC-DOOM. You still need a FinalExpansion3 or MegaCart for that (or if you're oldskool a slot expander with an extra 3K-expansion...)

I agree btw I have all the items you have suggested just to be safe

I bought this 32K memory Pack 5/6 years ago when I never thought to develop in the future a firmware for an item called Mega-Cart

leof · Post by **leof** » Thu Feb 16, 2012 5:03 am

The 64k version of the Memory Maker Pack also has a 2k EPROM. Is it possible to investigate what's in there? If so, how?

From http://virtualmagic.blogspot.com/2006/0 ... ic-20.html:
"The VIC-20's RAM was expandable with plug-in cartridges using the same expansion port as programs. RAM cartridges were available in several sizes: 3K (with or without an included BASIC extension ROM), 8K, 16K, 32K and 64K, the latter two only from third-party vendors. The internal memory map was reorganised with the addition of each size cartridge, leading to the situation that some programs would only work if the right amount of memory was present (to cater for this, the 32K cartridges had switches, and the 64K cartridges had software setups, allowing the RAM to be enabled in user-selected sections)."

Mike · Post by **Mike** » Thu Feb 16, 2012 3:03 pm

leof wrote:From http://virtualmagic.blogspot.com/2006/0 ... ic-20.html: [...]

I made a similar elaboration here in another thread: (link).

The 64k version of the Memory Maker Pack also has a 2k EPROM. Is it possible to investigate what's in there? If so, how?

That 2K EPROM probably maps into the address range $9800 to $9FFF. You could try to enter and run the following program, it will result in a file named "64K EXPANSION" being written to disk:

Code: Select all

1 SYS57809"64K EXPANSION",8,1:POKE193,0:POKE194,152
2 POKE780,193:POKE781,0:POKE782,160:SYS65496

Then please make that file available for download.

Greetings,

Michael

leof · Post by **leof** » Thu Feb 16, 2012 3:24 pm

Thanks for helping me with this cart Michael!
I looked into the area you mentioned with VICMON. There's no logic there. Do you still want the saved program?
Leo

Mike · Post by **Mike** » Thu Feb 16, 2012 4:48 pm

leof wrote:I looked into the area you mentioned with VICMON. There's no logic there.

You could also check the range of $0400 .. $0FFF with S1=off. Maybe the EPROM data hides there.

BTW, a RAM expansion in BLK1 takes precedence over the 3K one in $0400 .. $0FFF. In that case, screen memory is moved down to $1000, so the RAM for BASIC is contiguous from $1201 to $3FFF (and beyond), blocking the range of $0400 .. $0FFF from BASIC use. The VIC chip cannot access external memory, which means the screen memory cannot be placed at the very bottom, at $0400.

In that sense, the "11K", "19K", and "27K" settings make that RAM available, but it is only usable for ML programs.

leof · Post by **leof** » Fri Feb 17, 2012 5:32 am

Mike wrote:You could also check the range of $0400 .. $0FFF with S1=off. Maybe the EPROM data hides there.

Unfortunately there's nothing there either. I will now look into the entire ranges $1201-$7FFF and $A000-$BFFF.

leof · Post by **leof** » Fri Feb 17, 2012 6:52 am

I found something at $A800. So I saved $A800-$AFFF from VICMON. You can download it here: http://dl.dropbox.com/u/9954627/64KEXPANSION.PRG
I hope nothing did go wrong on copying it from VIC-20 to Amiga 4000 to Windows7 to Dropbox.

leof · Post by **leof** » Fri Feb 17, 2012 12:47 pm

leof wrote:I will now look into the entire ranges $1201-$7FFF and $A000-$BFFF.

With dipswitch #1 OFF and the rest ON I found a Ramtest program at $AD00.