C-128 VDC RAM upgrade

[+OLD CS1]

No, it's long gone. At some point after getting the Amiga I was tight on cash and sold my 128, two 1571s and one 1581. I including all the 5 1/4" floppies as they wouldn't work for the Amiga, the 3 1/2" were reformatted for the Amiga. The cash was used for either tuition, rent, or food, don't recall. In the past few years I've replaced everything except the 1581.

 

Proceeds from that kind of sale would buy a LOT of Ramen. At least back then when it was seven to 10 cents a package, now it is in the quarter-per range.

[+SpiceWare]

The gameplay was smooth and fast, though using the minus key only slowed it down just a tiny bit and using the plus key didn't seem to make a difference (though I may not have noticed if there was a slight speed-up).

You have to hold down plus for a while to really see a speedup. In the vertical bar that's colored red/yellow/green is a thin black line that shows what the current speed is. Game's noticeably faster when you get the line into the red.

 

That's one of those things in hindsight that I should have implemented differently, such as by using the numbers across the top of the keyboard to change the speed (so 1 would be the slowest speed, 0 would be the fastest, 5 half way between slowest/fastest) rather than +/- which only change it one value at a time.

 

It ran fine from the uIEC SD. However, when we tried to transfer the program file to a floppy disk for another club member and then when we tried to run it... fail! The game would crash. We'll have to try another way to transfer it to floppy disk.

I think I transferred it to my current setup by loading it off the uIEC then immediately saving it to floppy.

 

I implemented the sound effects by embedding BASIC statement parameters within the assembly language. To trigger a sound effect I'd fake out the BASIC kernel to think it was running a BASIC program and that it had just encountered the SOUND command. It's probable that trick confused BASIC about the size of the program, which would cause problems if you tried to save it after running the game.

 

binary view of the program on my Mac, the SOUND parameters for all the sound effects are in the red box:

---

The flying saucer's sound effect is generated on voice 1 using:

SOUND 1,5000,2000,2,3000,500,1

---

while this "sound effect" silences any active sound effect that's playing on voice 1:

SOUND 1,0,0

[+SpiceWare]

Proceeds from that kind of sale would buy a LOT of Ramen. At least back then when it was seven to 10 cents a package, now it is in the quarter-per range.

Yep - I worked at KFC back then and would take home left over chicken and break it up into the ramen for the protein. Didn't eat chicken for a long time after getting out of college

[RobertB]

SpiceWare wrote:

 

> You have to hold down plus for a while to really see a speedup.

 

Oh, I was just tapping the key.

 

> I think I transferred it to my current setup by loading it off the uIEC then immediately saving it to floppy.

 

That's what I thought I did, too. However, in the heat of the moment, I could have been mistaken.

 

> I implemented the sound effects by embedding BASIC statement parameters within the assembly language.

 

Thanks for the interesting details!

 

Will try again on my C128DCR set-up,

Robert Bernardo

Fresno Commodore User Group

http://www.dickestel.com/fcug.htm

 

Edited September 24, 2015 by RobertB

[CatPix]

I have wondered about these cards. They look well made and I highly recommend the 64k RAM upgrade for anyone with the C128.

 

I have a C128D, so likely without the full 64Ko of RAM. what is the advantage of having them?

[7800fan]

advantage:

some games won't run on stock 16k RAM

disc copy software can copy more and faster

cheap

 

Disadvantage:

can't wave magic wand and make 16k turn into 64k. No other reason unless you wanted stock 128's

[+OLD CS1]

 

I have a C128D, so likely without the full 64Ko of RAM. what is the advantage of having them?

 

In a 128D you do not need the upgrade. The 64k means more memory which means better graphics ability (double-buffering, for instance,) and extra memory used by various utilities (disk copiers, etc.)

[CatPix]

I'll check out on mine then - some people says that the C128D have the expansion RAM, other says that only then C128Dcr have it. I'll check that out with the command given at the start of the thread.

 

Thanks anyway ^^ I got the C128D because I wanted the combo C64 + floppy drive, and this one I got was cheaper than a regular C64 alone. All the best!

Plus I read that the power supll is better regulated, and I get all the C128 functions that I hope to use (at least in games).

So yeah I was curious about getting this extra RAM if I need it - when it's ready-made like in his link, there is no reason to refuse it.

[+OLD CS1]

I may have misspoke... I have no idea about the 128D being here in the 'States we have the 128DCR.

[motrucker]

I may have misspoke... I have no idea about the 128D being here in the 'States we have the 128DCR.

IIRC the 128 Dcr (metal case) is the only machine with 64K VDC. The 128D (plastic case) and C-128 both have 16Kb VDC.

[+SpiceWare]

Apparently this guy thinks a little game written to experiment with the VDC chip, and released into the public domain, should have AAA production values

[RobertB]

I consider it to be a fun, action game for the C128's 80-column mode!

 

Can't think of another fun, action game for the C128 80-column mode,

Robert Bernardo

Fresno Commodore User Group

http://www.dickestel.com/fcug.htm

[carlsson]

Be honored that he spent 11 minutes on a 30+ year old public domain game of yours, worrying whether those people who shelled out big money for a C128 really would pay ... $0 extra to get a game to play on it.

 

Edit: Also you get credit for more or less the entire part of the games industry that supported the C128 back in the day, and you're even awarded with a big wet burp in the middle of it all! It immediately got me thinking of burpware as a way to distribute software but I don't know exactly how it should work out.

Edited November 7, 2017 by carlsson

[JamesD]

There was a Star Trek type game that worked using C128 graphics if I remember right.
I bought it but never got a chance to try it before it burned.

[RobertB]

There was a Star Trek type game that worked using C128 graphics if I remember right.

That sounds like Starship Battles 128 by Micro Designs.

 

It ran very slowly,

Robert Bernardo

Fresno Commodore User Group

http://www.dickestel.com/fcug.htm

Southern California Commodore & Amiga Network

http://www.portcommodore.com/sccan

[motrucker]

The only version (port?) of this game I could ever play for more than 30 seconds without getting bored to tears was Better Dead than Alien for the Amiiga.

 

 

 

[unebonnevie]

Hi,

 

By any chance if there is a schematic on how upgrade the video RAM? Even text description is good. Basically, I just need to know which traces to connect to the higher RAM chips.

 

Thanks!

[+OLD CS1]

The information can be found (I bet at Zimmers,) but I recall all I had to do was replace the 4x16k chips with 4x64chips (41464.)

[motrucker]

The information can be found (I bet at Zimmers,) but I recall all I had to do was replace the 4x16k chips with 4x64chips (41464.)

It's that simple. Just replace the 16K chips with the 64K chips There are only two chips to replace.

[hlide]

How is that simple? How is the machine instructed its VDC ram is 64KB instead of 16KB by just swapping them?

[+OLD CS1]

I am pretty certain the VDC does not care how big its RAM is, it just sends out the address and either it gets data back or not. There are no special configurations of the memory map for 64k.

[motrucker]

Right now I am using a C-128 that had 16Kb of video RAM, but has had the Chip Level Design board added, and it now has 64Kb according to all of the software I use with this computer. There is a cap on this board, that doesn't seem to be on the C-128 motherboard, but I am not 100% sure of that. I do know this board works. (The only chips on the board are two 41464 RAM chips.)

 

Best way to answer any question about this, would be to ask Bil Herd, on his site.

 

http://c128.com/

Edited January 2, 2018 by motrucker

[hlide]

Ok, I think people should really distinguish between KB and Kb. The first is mostly used to say KByte and the later to say Kbit. As far as I can see, there are only TWO chips used as a VRAM for the VDC chipset. So we are speaking about turning 2 x 16K x 4 bits into 2 x 64K x 4 bits.

Let see the pin layout of those chips:

PIN    16K x 4bit (4416?)    64K x 4bit (41464)
1      nOE                   nOE
2      DATA                  DATA
3      DATA                  DATA
4      nWE                   nWE
5      nRAS                  nRAS
6      ADDR                  ADDR
7      ADDR                  ADDR
8      ADDR                  ADDR
9      VCC                   VCC
10     ADDR                  ADDR
11     ADDR                  ADDR
12     ADDR                  ADDR
13     ADDR                  ADDR
14     ADDR                  ADDR
15     DATA                  DATA
16     nCAS                  nCAS
17     DATA                  DATA
18     GND                   GND

Their pins match (data and address order don't matter).

I suppose if you try to access beyond 16KB with a 16KB version, you may have a mirrored 16KB or random bytes.

 

Well, I guess it is safe to swap them indeed.

 

As for the solder-less plug-in, I'm not expecting it to be safe because I wonder how the plugin is shutting the original RAM chips and how it tries to reroute some data. As for the capacity on the plugin board, it may be needed between a pin of the VDC chip and a pin of the two new RAM chips.

Edited January 3, 2018 by hlide