Better Donkey Kong?

[Better Donkey Kong?]

First, I ADORE the CV version of Donkey Kong. But there are missing pieces from the arcade.

 

I'm aware of the SGM version but I don't have one of those.

 

So I was wondering if there was a homebrew 32k version perhaps?

[Schematics for ADAM module 3]

Awesome thanks!

[How do CV carts work?]

Ah I missed that. So does that mean 32k is the max cart size? How do the four extra lines work?

Thanks.

[How do CV carts work?]

Ok, stupid question here. lol. Anyway, I'm really trying to learn the internal workings of the CV.

 

When I look at he cartridge port, I see what appears to be A0-A13 which gives 16k. Ok, next I see EN8/A/C/E. So, when power on how does the CV use those 4 lines compared to the 16k? And how were 24 or 32k carts made?

 

Thanks for any detailed info.

[Schematics for ADAM module 3]

I've looked and looked but cannot find the schematics for the ADAM module for the CV.

 

Any idea where I can get that?

 

Thanks.

[What could be wrong with my new ColecoVision?]

I have an ADAM. Love it. But the damn thing takes up half my office. Lol.

 

My dream is to build my own "CV1.2" like console. It would be driven by a propeller for video and other things with a real Z80. Just need to get off my butt and build it. Lol

[What could be wrong with my new ColecoVision?]

I only have one power supply. But it's confirmed working.

 

Anyone know of any SRAM replacement mods?

[What could be wrong with my new ColecoVision?]

Yeah, I was afraid of that. I might look into possibly replacing with SRAM. Of course that would be a major mod.

[What could be wrong with my new ColecoVision?]

So I bought two CV's off eBay for <$20 each. Both were reported not working.

 

I managed to clean and mod the first one and it works like a champ.

 

However, my second one isn't working correctly. My suspicion is bad memory. The unit powers up, the audio sounds fine but the screen is all messed up.

 

But, it's messed up in a "bad data" type of way. For example, instead of saying "GET READY PLAYER 1" it says "GEP REAWY PCAYER 1". The game select screen says "PPRQQ @UTTML ML IEYPAD"...etc.

 

(screen shots attached).

 

So, what are your thoughts? I've cleaned it up physically. In fact, this was one of the cleanest units I've ever seen. Looks almost mint besides a little dust.

 

All of the electrolytic capacitors are fine. Well, they aren't bulging and there is no leakage.

 

I didn't take the RF unit apart to see if anything was leaking under it but I don't think that is the issue anyway since it isn't a bad picture for RF. Just looks like the letters have been replaced, colors swapped, etc.

 

Thanks.

[7800Basic Horizontal Scrolling]

This is insanely great. So who's going to do Zelda?

[Could an AVR be used as a cart rom?]

Ah good point. BitBanging at that speed would be an issue for an AVR.

[Could an AVR be used as a cart rom?]

So, say I find an AVR with a high pin count and lots of FLASH. Could that be used as a ROM for a cart?

 

Or would you need glue logic in between like a PLD?

[Any SD homebrew carts out there?]

I was wondering if there is a cart for the CV that takes SD cards and runs binary files? Like a multicart of sorts.

 

One reason I ask is that I would like to transfer my own programs over for testing.

 

Thanks.

[Montezuma's Revenge so expensive!]

Sorry, wrong place. How can I move this to the right place?

[Montezuma's Revenge so expensive!]

More eBay gouging. I saw a couple copies for $20ish but several for over $50.

 

Ugh that ticks me off.

 

Anyone know of a better deal?

[Coleco pause button]

Sweet. thanks.

[Coleco pause button]

I saw a YouTube video of a CV mod that had s pause switch. When paused, the CV stopped completely.

 

How was this done?

 

I'm not that familiar with the Z80.

[Questions about Coleco graphics capacity?]

Thinking about this a little more....I think it's more accurate to say that instead of "320 pixel bandwidth" to say "active display bandwidth" from the 63.55uS NTSC scan line.

 

So, to draw 40 chars at 6 pixels leaves no more bandwidth left for sprites.

 

Either way, the active display area is the same in all modes but at 256 pixels there is barely enough time left to deal with sprites.

 

Again, amazing for 70's technology.

[Questions about Coleco graphics capacity?]

You sure? It may be 6 pixel fonts but 256/6 != 40.

It may be shifting the chars over 2 pixels to get 6 pixel fonts but the bandwidth should still be 320.

 

But I could be wrong.

[Super Game Module Schematics]

I did a while back. From what I read he is MIA.

[Questions about Coleco graphics capacity?]

I've read most of this thread and found it really entertaining.

 

One theme I saw a few times was about the 4 sprite per horizontal line limitation. Some even called it stupid.

 

It's understandable, not stupid. First, the TMS99x8 was designed in the 70's. Second, it's easy to understand why the limit was there. Bandwidth. So in text mode, we have 40 characters which equals 320 pixels of bandwidth. But no sprites. In mode 1/2, we have a resolution of 256. 320-256=64. 64/16 pixels (max sprite width) = 4. Bam. 4 sprites.

 

Now, why can't we have 8 sprites at 8 pixels? My guess is because there is overhead in changing sprite pointers, colors, etc. and that tiny bit of overhead wouldn't fit in the 320 pixel bandwidth.

 

Anyway, just my $0.02.

[Super Game Module Schematics]

I would love to aquire one. But I don't think they are made any more are they?

 

Another reason I would like the schematics is that I would like to build some modules myself. Not unlike the SGM but not like it either. I'd like to experiment with putting a SID chip on there using the SIDCog running on a propeller.

[Super Game Module Schematics]

Is that basically what it is? More RAM and another SN76488 (or clone)? Not that isn't great. :-)

[Super Game Module Schematics]

Ah, didn't know it use CPLD. Either way, would be nice to have schematics, code, etc so others could build. Seems like a great project.

[ColecoVision 1.2 - replacement PCB, added features]

Ah. I read that but missed the posted date.

 

Cool. Hopefully this will become a real product this year.

 

On a side note, this project is very close to what I've wanted to do. For a while now, I've dreamed of designing a Coleco "compatible" computer. I know there is ADAM and MSX but have you priced those lately? Lol

 

Anyway, my idea was to use new parts only and perhaps try to get audio and video through a Parallax Propeller.

 

Oh well, if/when I get beyond the breadboard with my design I will let people know.