vic-1110 8k ram cart upgrade (and other solutions)

[eslapion]

Did I interpreted it correctly?

Yup!
Just add a small 10k resistor between switch S1's pin 3 and VCC. It is preferable not to connec the !WE input of the SRAM chip directly to 5V.

I got the info from:
http://www.zimmers.net/anonftp/pub/cbm/ ... /32kB.html
perhaps there is an error…

There is more than one actually.

[Mike]

This is probably for compatibility with self modifying code cartridges but as demonstrated with the game Crazy Antics, you MUST place in read-only mode ALL the RAM for full compatibility with dumped cartridges.

I had to try this out.

With the NTSC dump on zimmers, I could successfully run K-razy Antiks only with BLK3 and BLK5 attached as ROMs (in RAM, it bombs out as you wrote), but at least I could fill BLK1, BLK2 and $0400..$0FFF with writable RAM without the game mucking up.

There are some games, notably Bug Crusher, which won't run alongside a +8K (or more) RAM expansion, as they don't initialise the screen correctly - they rely on the screen being at $1E00 but still execute that part of the KERNAL reset routine which ultimately puts the screen base at $1000 because of the RAM expansion present at BLK1.

My VFLI mod however leaves the screen base at $1E00 regardless when there's no other external RAM expansion attached, and I still have to see an example game cartridge which 'complains' about the extra RAM at $0400..$0FFF.

[eslapion]

This is probably for compatibility with self modifying code cartridges but as demonstrated with the game Crazy Antics, you MUST place in read-only mode ALL the RAM for full compatibility with dumped cartridges.

I had to try this out.

With the NTSC dump on zimmers, I could successfully run K-razy Antiks only with BLK3 and BLK5 attached as ROMs (in RAM, it bombs out as you wrote), but at least I could fill BLK1, BLK2 and $0400..$0FFF with writable RAM without the game mucking up.

My bad, I should have specified...

You MUST place in read-only mode ALL the RAM occupied by the game code.

However, since the game occupies BLK3 and BLK5, it will definitely crash if you put only BLK5 in read-only mode.

[lordbubsy]

Thanks eslapion and Mike
My "prototype" is working!

I'll just have to rebuild it a little neater and add some switches for controlling ON/OFF, READ-WRITE/READ-ONLY and RESET.

[DELETED]

DELETED

[craftsman1234]

A big thanks from me as well, works great, although doesn't look too professional, not that I care about that. Does look a lot better with the
cover attached of course. I superglued the 74ls08 to the pcb just in case
anyone was wondering. Only had a 1k resistor handy, I imagine that should be ok, but can change to a 4.7k or 10k later if that is better?

imperiousVIC,

I'm looking at doing this as well. Do you happen to have a parts list for everything you need. I would be good to have a diagram to show where all the wires are going to/from. I know that one switch is reset. What does the other do?

I believe you said that you used a Radar Rat Race cart.

Thanks

[Richardc64]

If you have a VIC-20cr, you can actually have the 32k x 8 installed inside your VIC by piggybacking it on top of one of the 2 2k x 8 SRAM chips and add the 74LS08 somewhere on top of the glue logic chips.

You'll get a VIC-20 with internal 32k ram expansion.

My mothballed VIC has 76.5K inside. http://www.sdiy.org/richardc64/vic20/vic01.html

[Mike]

Now how cool is this? I had no idea you had registered here on Denial! End of last year, I posted a link to your site in the thread 'What is happening here?'.

My mothballed VIC has 76.5K inside.

If you add in another 16Kx4 SRAM in place of the colour RAM, your VIC-20 would also be able to display VFLI pictures. See the thread 'Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!': you could simply connect the extra 4 address lines to the user port as I did, or you can use a readable latch register in your I/O expansion areas at $914X/$915X - this needs just a small adjustment in the display routine.

[Richardc64]

Now how cool is this? I had no idea you had registered here on Denial! End of last year, I posted a link to your site in the thread 'What is happening here?'.

My mothballed VIC has 76.5K inside.

I missed that.

I had to reactivate my account. I first registered when I saw that wimoos had incorporated my port of C64 SuperNumbers to Vic-20 into his WimBasic.

If you add in another 16Kx4 SRAM in place of the colour RAM, your VIC-20 would also be able to display VFLI pictures. See the thread 'Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!': you could simply connect the extra 4 address lines to the user port as I did, or you can use a readable latch register in your I/O expansion areas at $914X/$915X - this needs just a small adjustment in the display routine.

First I'd have to find my VIC-20. I know it's in a box marked "modified vic" but I don't know where the box is

[craftsman1234]

I did! Works great!

You even have one left IC footprint if you want to add the 3k RAM section or some ROM upgrade.

I did this back around 1994. Never had to modify or repair my boosted VIC-1110 since. I even added a small reset pushbutton.

There are hundreds of different brands of 8k x 8 static RAM which will do the job.

This is one of them:
http://www.ebay.ca/itm/LH5164A-80L-SHAR ... 3cbb3d5162

I finally picked up two 8k VIC-1110 boards and want to expand one to 16k or higher. Do I understand you correctly that you need to get two of these chips and then leave the other socket empty. The two additional chips will make it a total of 16k. What is the socket size needed?

[eslapion]

I finally picked up two 8k VIC-1110 boards and want to expand one to 16k or higher. Do I understand you correctly that you need to get two of these chips and then leave the other socket empty. The two additional chips will make it a total of 16k. What is the socket size needed?

Each extra chip adds 8k so adding 2 chips will make you 24k, not 16k.

No socket is needed at all. The 8k x 8 SRAM chips are mostly pin compatible with 2k x 8 SRAM chips and there are 3 unused footprints on the VIC-1110 board. Simply put the extra chips in the unused footprints and wire the extra leads manually using the smallest type of wire you can get. Usually 40 awg wire used for wire wrapping will do fine.

[craftsman1234]

I finally picked up two 8k VIC-1110 boards and want to expand one to 16k or higher. Do I understand you correctly that you need to get two of these chips and then leave the other socket empty. The two additional chips will make it a total of 16k. What is the socket size needed?

Each extra chip adds 8k so adding 2 chips will make you 24k, not 16k.

No socket is needed at all. The 8k x 8 SRAM chips are mostly pin compatible with 2k x 8 SRAM chips and there are 3 unused footprints on the VIC-1110 board. Simply put the extra chips in the unused footprints and wire the extra leads manually using the smallest type of wire you can get. Usually 40 awg wire used for wire wrapping will do fine.

eplspion are there any pictures of this wiring set up? I hate to say it but I do better with pictures. I'd like to use sockets as there are less chances of me damaging the memory chips.

[eslapion]

eplspion are there any pictures of this wiring set up? I hate to say it but I do better with pictures. I'd like to use sockets as there are less chances of me damaging the memory chips.

If you use sockets then there's a chance you won't be able to close the case anymore.

I don't see why you need pictures. The pinout for 2k x 8 SRAM chips vs 8k x 8 SRAM chips is pretty standard.

[eslapion]

I know... I took a loooong time for this one...

[eslapion]

Can somebody be kind enough to add the above photo this this Wiki page: http://sleepingelephant.com/denial/wiki ... _Cartridge