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PostPosted: Fri Nov 11, 2016 5:37 am 
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Joined: Mon May 27, 2013 9:40 am
Posts: 351
I was going to use a pattern compression scheme based on LZSS by tokumaru which works nice and is fast enough. I don't care leaving the user sit for a couple of seconds between scenes. [*]

Memblers wrote:
If you do want to consider a newer (but cheap/simple) mapper with 512kB, one of them is my own GTROM aka Cheapocabra. It has bankswitched CHR-RAM, and bankswitched nametables. It doesn't have WRAM, but it does have extra PPU memory at $3000-$3EFF that can be used without affecting any graphics. It does have some emulator support in FCEUX.
http://forums.nesdev.com/viewtopic.php?f=4&t=12716


I will check that out too, thanks.

[*] BTW, the original compression routine by tokumaru was coded using WSH and was kind of slow. I ported it to freebasic, in case somebody is interested. A tad faster, and portable.

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PostPosted: Fri Nov 11, 2016 9:26 am 
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Joined: Tue Oct 06, 2015 10:16 am
Posts: 558
lidnariq wrote:
So ... given that na_th_an explicitly is trying for something cheaper than MMC3 ... and that adding PRG RAM will increase the cost to manufacture by at least 33% ... you're advocate using zlib rather than a compression format that's actually designed for the paucity of RAM in the NES because ... you don't like by told you're wrong??

Zlib is explicitly a bad match for the NES. There already exist solutions that are good matches that don't compress tremendously worse.


The cost difference between MMC3 and simpler mappers is far greater than the cost of WRAM, again according to INL. I have quoted my sources, you have not. According to what numbers is 1.35$ an increase of 33%? If that were true, you could get a board without RAM made for 4$, including the mapper and soldering work.

zlib has superior compression to any other compressor available on the NES, according to benchmarks I made and posted here. Using a less efficient one to save money is just fine, but you have not shown it would be a significant difference.

I do like being told I'm wrong, but I'm right in this case ;) Unless you can show me where I can get MMC1-level boards made for 4$.

edit: Corrected the cost, it's 4$.


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PostPosted: Fri Nov 11, 2016 10:42 am 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 6287
Location: Seattle
Cost of a SST39SF010 FLASH ROM in qty 100: $1.02
Cost of a IS62C256 5V SRAM in qty 100: $1.25
Cost of a 74HC161 in qty 100: $0.25
Cost of a 74HC20 in qty 100: $0.20
Cost of at ATTiny13 in qty 100: $0.90 (avrciczz)
Cost of a PCB made the cheapest way: $0.50/ , give or take, by panelizing three boards onto one 10x10cm producing thirty boards using one of the "ten 10x10cm boards for $10+shipping" deals

Cost of the now-deprecated XC9536XL: $1.54 per, now, but it's all new-old-stock, will run out before too much longer, and there's no volume discounts anymore. (MMC1 class)
Cost of the now-deprecated XC9572XL: ≈$3 per, same caveats. (two make MMC3 class)
Cost of a voltage clamp and 3V CPLD MAX3000A: ≈$3 per

Cost of hard gold plating on the card edge: $2 per (q.v. memblers)

You can do the math. I stand by $4 as a good proxy for a discrete logic boards that lacks PRG RAM.


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PostPosted: Fri Nov 11, 2016 11:33 am 
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Joined: Tue Oct 06, 2015 10:16 am
Posts: 558
Thanks. Soldering everything yourself, for more than a couple boards is not something I'd do at least.

4$ vs 5.35$, on a board sold for 30-60$? The difference is insignificant to me, but you're right about the 33% increase.

FWIW, Aliexpress lists that SRAM, qty 100, for 0.64$.


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