If Technology is *this* Advanced...

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WJYkK
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If Technology is *this* Advanced...

Post by WJYkK » Fri Jan 21, 2011 11:46 pm

Here's something I've been thinking about recently. Now, I'm not an expert in making NES cartridges (not that I ever had one, physically), but I always wondered: if we're so far technologically advanced that yesterday's invention costs pennies, what stops us from inserting RAM sticks and SD cards into NES cartridges rather than using those chips found in a typical NES cartridge?

It may sound a bit like a dumb question, but if it just not possible to do, why not?

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Post by Memblers » Sat Jan 22, 2011 12:09 am

It's a good question. The short answer is compatibility. You could use DRAM or SD cards with NES, but not without some kind of memory controller. But the mapper will cost more than the 'usual' memory would.

NES is best suited for asynchronous SRAM and NOR Flash (SD cards use NAND flash). It's not exactly obsolete, but it is more expensive than DRAM and NAND (both synchronous).

I have a plan for a memory controller to make later on, that should be able to use an SD card in a really fast way.

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Post by koitsu » Sat Jan 22, 2011 1:01 am

I thought that's effectively what the PowerPak did?

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Post by WJYkK » Sat Jan 22, 2011 1:09 am

koitsu wrote:I thought that's effectively what the PowerPak did?
Except that not all of us can afford paying $135 for this product. I'm more referring to making a cartridge from parts rather than having it all ready for you. Plus, you wouldn't really want to redistribute this cart if you, for example, made a/n NES game and want to sell it, now would you? Because otherwise you'd have to sell it for over $135 and disable copying, and I'm not sure if anyone would like to pay so much for a cart.

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Post by koitsu » Sat Jan 22, 2011 5:40 am

WJYkK wrote:
koitsu wrote:I thought that's effectively what the PowerPak did?
Except that not all of us can afford paying $135 for this product. I'm more referring to making a cartridge from parts rather than having it all ready for you. Plus, you wouldn't really want to redistribute this cart if you, for example, made a/n NES game and want to sell it, now would you? Because otherwise you'd have to sell it for over $135 and disable copying, and I'm not sure if anyone would like to pay so much for a cart.
Who would make a commerical NES game that contained (used) SD cards or RAM sticks? Mask ROMs are significantly cheaper compared to either of those. So I guess I'm having trouble following the train of thought here with regards to your OP. :-)

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Post by WJYkK » Sat Jan 22, 2011 11:41 am

koitsu wrote:Who would make a commerical NES game that contained [...] RAM sticks?
Well, what if I need to have more memory for some reason? If I could, I would be able to buy a pack of cheap RAM sticks for $10 and stick one in the cart.
koitsu wrote:Mask ROMs are significantly cheaper compared to either of those.
There are a few problems though. First, the cost of writing to it is not that cheap, although I don't know how much it is exactly. Secondly, if you write to it incorrectly, you're screwed. And finally, where will you find these chips where you can buy these and how are you going to upload the data to the ROM?

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Post by 3gengames » Sat Jan 22, 2011 12:34 pm

$10 ram sticks in a cart would be far more expensive then $0.50 chips with a $75 payment for the programmer. Plus, there's no reason for more RAM in carts, 32K WRAM is more then enough with SXROM, even if you can exhaust the 8K WRAM in most other RAM games. If you need more, you should consider moving to another more advanced system or making more optimized use of the RAM. :)

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Post by Memblers » Sat Jan 22, 2011 1:21 pm

OTP EPROM is cheapest, but even with Flash it might only be $2 for 512kB. 32kB SRAM is under $1 if you go cheapest from unknown/various manufacturers. 512kB of SRAM is maybe $5? Price-wise it's going to be tough to beat that. Using a DDR-SDRAM like PC memories do would at least require a CPLD or FPGA, and using an SD card would require a microcontroller. Then you also need a crystal, capacitors, and a power supply. NES runs on 5V, while newer stuff runs on 3.3V, 1.8V, and even lower. You can get that from the 5V, but still it's just more stuff - the costs and complexity is piling up fast, compared to the single-chip solution.

I too am really interested in getting access to large amounts of memory for the NES. One of the first things I wanted to do (before I knew how to do PC stuff) was connect the NES to the PC for storage. I thought it would be hilarious to see the NES report "36.5 GB free" or something. Since then though I had been thinking it would be better to have a device that would be on the NES expansion port, or controller port, that would basically be an SD card reader. Or USB host, where you could use a USB memory stick. That way you could use the SD card with any NES cartridge. I guess you could even distribute the game as a memory card.

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Post by tepples » Sat Jan 22, 2011 3:45 pm

Mask ROM is a custom integrated circuit. Just as with CDs you have to make a glass master, with mask ROM you need to make a "mask", or pattern that is etched into the silicon. As I understand it, it becomes less expensive than flash after a few thousand (or hundred thousand?) copies, which homebrew is unlikely to sell especially if it doesn't run on NOAC-based clones.

One advantage of mask ROM is that you can theoretically put the mapper and PRG ROM circuitry in one package. But one advantage of flash, as long as the sectors aren't huge, is that you can reserve some of it for saving so that you don't need a battery on your PRG RAM.
Memblers wrote:OTP EPROM is cheapest, but even with Flash it might only be $2 for 512kB.
Like this SST39SF040?
NES runs on 5V, while newer stuff runs on 3.3V, 1.8V, and even lower.
But as I understand it, 5.0 V parts aren't going away any time soon because they're common in automotive computers.

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