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PostPosted: Tue Apr 26, 2005 7:30 pm 
Hello. I am completely new to this all, but have recently become very intested in the NES scene. I have been using google a lot to find what I know thus far, but so far I found a lot of information on dumping, but little on writing. What I have found, is very dense. Does anyone know one place I can go that can really just boil it all down a bit for me? Keep in mind, I am completely new to this all. Thanks in advanced.


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PostPosted: Wed Jun 01, 2005 8:50 am 
You'll need an EPROM burner.

Also, check out this link:

http://www.zyx.com/chrisc/solarwarscart.html


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PostPosted: Wed Jun 01, 2005 1:18 pm 
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Depends on what you want to rewrite it for. Developing, or running older games? If you want to reuse the older carts, you'll need one for each needed mapper type (and most of them need rewiring) and a chip programmer.

I've developed an NES flash cart I call Squeedo. It can be re-written while it's running in the NES, and it connects to a PC's serial port. I'll be building a batch of them pretty soon. It's good for development, but not as useful for running older stuff. It can run Solar Wars though, heh.


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PostPosted: Wed Jun 01, 2005 1:25 pm 
Memblers wrote:
Depends on what you want to rewrite it for. Developing, or running older games? If you want to reuse the older carts, you'll need one for each needed mapper type (and most of them need rewiring) and a chip programmer.

I've developed an NES flash cart I call Squeedo. It can be re-written while it's running in the NES, and it connects to a PC's serial port. I'll be building a batch of them pretty soon. It's good for development, but not as useful for running older stuff. It can run Solar Wars though, heh.


Is this flash cart project available online or is it private domain? :? Also, why it isn't "useful" for older games? Can you go a little further of maybe point to another thread?

Thanks in advance! :D


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PostPosted: Wed Jun 01, 2005 6:52 pm 
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I haven't made a website for it yet, I still need to do that. And write some docs.

The main reason it won't work with older games is because the mirroring. The cart disables the NES's 2kB internal VRAM, and replaces it with a full 4kB VRAM (usually called 4-screen mode). This screws up the scrolling if a game relied on the RAM being mirrored.

Also, the bankswitching is pretty coarse and simple. PRG-ROM uses 32kB banks, and CHR and WRAM are both 8kB pages.

More info is here:
http://nesdev.com/bbs/viewtopic.php?t=15

I'll post new pics in that thread tonight.


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PostPosted: Wed Jun 01, 2005 7:54 pm 
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Memblers,

Would it be possible to write a small ROM for squeedo that could be used to dump a game cart's SRAM and ROMs by swapping between Squeedo and the game cart to be dumped over and over again? Each time the game cart is inserted, the running program copies a little more of the ROM into the NES's RAM, and once the RAM is filled, Squeedo is inserted to copy that data to Squeedo. Repeat until fully dumped. Sure it is a total hack, but it would be an interesting trick. Of course, a different version of the small NES program would have to be written for each mapper... like the CopyNES plugins.


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PostPosted: Thu Jun 02, 2005 5:05 am 
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Jagasian wrote:
Would it be possible to write a small ROM for squeedo that could be used to dump a game cart's SRAM and ROMs by swapping between Squeedo and the game cart to be dumped over and over again?


Yeah, it may be possible. Sounds like a lot of work to dump like that, though. NES only has 2kB of RAM, so even dumping the smallest (24kB) NES cart this way would require swapping carts over 12 times. A much better solution would be if I make more NES controller port versions of my serial adapters (I suppose I could, if people actually want to use them - I offered them before), that way you only need to swap carts once, since the COM port would always be available.


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PostPosted: Thu Jun 02, 2005 5:17 am 
Memblers wrote:
I haven't made a website for it yet, I still need to do that. And write some docs.

The main reason it won't work with older games is because the mirroring. The cart disables the NES's 2kB internal VRAM, and replaces it with a full 4kB VRAM (usually called 4-screen mode). This screws up the scrolling if a game relied on the RAM being mirrored.

Also, the bankswitching is pretty coarse and simple. PRG-ROM uses 32kB banks, and CHR and WRAM are both 8kB pages.

More info is here:
http://nesdev.com/bbs/viewtopic.php?t=15

I'll post new pics in that thread tonight.


Thank you very much for your care. This is an awesome community! :D

I'll check this link ASAP


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PostPosted: Thu Jun 02, 2005 6:49 am 
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Memblers wrote:
Jagasian wrote:
Would it be possible to write a small ROM for squeedo that could be used to dump a game cart's SRAM and ROMs by swapping between Squeedo and the game cart to be dumped over and over again?


Yeah, it may be possible. Sounds like a lot of work to dump like that, though. NES only has 2kB of RAM, so even dumping the smallest (24kB) NES cart this way would require swapping carts over 12 times. A much better solution would be if I make more NES controller port versions of my serial adapters (I suppose I could, if people actually want to use them - I offered them before), that way you only need to swap carts once, since the COM port would always be available.


I must have missed the offer. Got a link, or can you repost the offer? I think that it would be a worthwhile official extension to Squeedo: package it with a controller port cable and NES program plugins for dumping/writing cart ROMs, SRAM, and GAR SRAM. Though that would put your Squeedo in direct competition with the CopyNES :)

Did you ever try making a NES to NES controller port cable, so that two NES's could talk?


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PostPosted: Thu Jun 02, 2005 8:10 am 
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It was on the old forum, and since I don't have a website for it either I guess not many have seen it, heheh.
http://nesdev.com/cgi-bin/wwwthreads/showpost.pl?Board=hardware&Number=617&page=&view=&mode=threaded&sb=#Post617
I'd sell one I suppose for not more than $15. But also it needs a dev cart to function anyways.

It don't think it can compete with CopyNES though. I certainly wouldn't advise hot-swapping game action replay prototypes and stuff like that, heheh. It's seems pretty likely that SRAM data on games too could be corrupted (the "hold reset when shutting down" type of thing). And getting bad dumps would be annoying, but maybe not as bad on a top-loader.

Jagasian wrote:
Did you ever try making a NES to NES controller port cable, so that two NES's could talk?


That would work, I believe Codemasters did something similar to that when they were testing Micro Machines. Even simply using 2 plugs cross-wired would work, but poses problems for the software (since they'd need to be sycned or always polling the port). I haven't tried it myself, but now that I got a 2nd NES I should give it a shot sometime.

What'd be even better is 2 NES's with 2 Squeedo carts. Since it uses the PIC's hardware UART, it takes up none of the NES's cpu time. And it should be able to work over the internet. :D


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PostPosted: Thu Jun 02, 2005 8:43 am 
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Memblers wrote:
What'd be even better is 2 NES's with 2 Squeedo carts. Since it uses the PIC's hardware UART, it takes up none of the NES's cpu time. And it should be able to work over the internet. :D


I was just thinking about a local setup, with two NES systems networked. Imagine a new Contra where one player didn't kill his buddy when he jumped up to the next platform too quickly (like the 3rd level in the original Contra). Of course, if two NES's can network locally via a Squeedo to Squeedo link, and the game wasn't extremely latency sensitive, then I guess you are right in that you could proxy the data over the internet. The key thing will be getting all home-brewers to use Squeedo as their development cart.

I guess I will wait until I can buy the controller-port serial cable along with a Squeedo. Have you finilized the Squeedo design yet? I saw that you changed to a much smaller PCB. Also, I thought that some PICs had native USB support (those Retropad USB NES controller adapters use a PIC as the main and only IC). Since you are using one of the more capable PICs, why not just go with a USB interface on the Squeedo?

Also, how are all of those Atari hardware homebrewers getting plastic cart cases made so inexpensively, such as the Krokcart? Will Squeedo have a plastic case with a non-hacky hole for its serial interface?


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PostPosted: Thu Jun 02, 2005 10:17 am 
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I went with RS232 instead of USB because it's a lot simpler, no special drivers or software is needed. Just a standard terminal program with XMODEM, at the very least. It'd be possible to make a USB adapter for the rev1 Squeedo with the current PIC, but the USB transceiver chip itself costs $5 or so, and it needs more components still.

Any 5V circuit can hook up to the rev1 Squeedo, it supplies 4 I/Os plus VCC/GND. The rev2 (smaller) Squeedo I/Os are RS232-level off the board instead of 5V, that's the main difference. I also need to do testing with the address latch on the rev2 design. But the rev1 design is stable and finalized.

I posted new pics in the hardware forum.

For the Atari carts, most of them are just using recycled cases. The newer cases aren't too cheap. Someone either payed big bucks, or did a lot of work creating a mold for them. That's the big cost with making cases.

I've designed my cart in way that I can produce as many of them as needed, but there are no plans for custom cases.


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PostPosted: Thu Jun 02, 2005 10:49 am 
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Given the Rare-style bankswitching, I'm not so sure about Squeedo's compatibility with DMC sounds in a game larger than 32 KB.


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PostPosted: Thu Jun 02, 2005 2:42 pm 
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tepples wrote:
Given the Rare-style bankswitching, I'm not so sure about Squeedo's compatibility with DMC sounds in a game larger than 32 KB.


The $C000-$FFFF region can be mirrored by the loader program (in the cart BIOS). I'll have it do that automatically depending on the iNES header, I suppose for mapper #2. That way you'd be able to bankswitch up to 224kB PRG with a fixed bank for DPCM samples.

Since there's 32kB of RAM, one thing I plan on doing in my game is storing only compressed data in most banks. So that would mean no sample playing during loading. But I could always use $4011 instead, heheh.


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PostPosted: Wed Jun 08, 2005 10:34 pm 
memblers Hello!
I havea question to you

would you be able to sell me a cartridge that plays rom from pc to the real nintendo??

is it complicated to do & to put a rom inside the cart?
i wanna play megaman & other games.

how much does this Squeedo Sell for??$$$
tell me

thanks my friend!!!


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