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PostPosted: Thu Sep 03, 2009 7:20 pm 
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Bregalad wrote:
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It's actually really easy to save/load data over the controller port to an RS232 port. Besides ground, it only needs 1 input (controller data) and 1 output (controller strobe). I think some older computers often used 5V serial ports, so in that case it could be wired up directly with no voltage translator. Building one of those MAX202 circuits and getting XMODEM protocol working with NES was my 2nd hardware project (and the first one that I did mostly on my own).

Sounds cool, but it should have been hard to get the timing for exact asynchronous communication.

It's actually quite error-tolerant, since crystal speeds varied between computers, modems, and probably temperatures. A hardware UART checks the input I think at least 8 times per bit, and the value set for the longest time 'wins'. In software for receiving you just delay the time for 1.5 bits after start, so it's right near the 'center'. And if the timing is off a little (or even a lot, at lower baudrates), it only has to stay roughly in sync for 8 bits - so there's little time for any error to accumulate before it re-syncs for the next byte. It's much more forgiving than doing timed PPU tricks. blargg even got this to work while the DPCM channel was playing (and Bananmos got PPU tricks to work while DPCM channel was playing in "Years Behind", but that's a whole other impressive bit of hacking, heheh).

Timing formula if you're curious for NTSC is roughly 1789000 / baudrate. 93 NES cycles per bit at 19200 baud (what I used), and a whopping 745 NES cycles per bit at 2400 baud.

It really tempts me to pick up that idea again for general production, since more people are hacking with the hardware these days I think it'd make a fairly compelling little accessory if done with USB and sold cheaply enough to where it's hardly profitable (d'oh!).

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I don't know about you guys, but there are times when I'm feeling so lazy that I guess a few combinations of signs/values/whatever and compile to see what works in a particular logic block. Sometimes it's faster than actually doing the math or tracing the code in my head, if the options are limited.

Yeah usually I just try stuff and see what happens in FCEUX. If it would take hours to compile, never I could do this. And when doing raster effect, I add and remove a few cycles and try different things. If It'd take hours to compile, again I don't know what I'd do.


I remember watching kevtris working on his FPGA NES just a few years ago, when he made a change and compiled it, it really would take hours to complete..! Computers are a little faster now (dual and quad-core sure helps), but that still seems like an amazingly intensive modern-day compilation process.

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I'd imagine that the CHR RAM boards might have been cheaper because there wasn't a mask setup cost for the CHR ROM; 6264 SRAM was a common off-the-shelf part that could be used across all such titles. Was this the case?


May be cheaper to start up, but I'd imagine for a game like SMB3 or something where they knew they would sell tons of copies, MaskROM may have ended up being the same cost or cheaper in the long run. And RAM being a commodity, perhaps may have been subject to price fluctuations. Just my guesses.

Also regarding the cost to publishers, the impression I got from reading some interviews was that Nintendo actually made their publishers pay up-front to produce a pretty large minimum number of carts. So publishers were taking a risk, while Nintendo was set to make money even if the carts were scrapped. No wonder Nintendo was so successful, and Atari/Tengen was so eager to set out on their own making unlicensed carts.


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PostPosted: Fri Sep 04, 2009 12:38 am 
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Oh about the UART I guess as long as the baudrate is low it should be pretty tolerant.
And yeah that Years Behind demo is beyond awesome if someone could provide the sourcecode of it it would be great. Probably the best NES demoscene ever, altough High Hope is as good, and Sayonara is pretty cool either.
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Also regarding the cost to publishers, the impression I got from reading some interviews was that Nintendo actually made their publishers pay up-front to produce a pretty large minimum number of carts. So publishers were taking a risk, while Nintendo was set to make money even if the carts were scrapped. No wonder Nintendo was so successful, and Atari/Tengen was so eager to set out on their own making unlicensed carts.

Yeah there were taking a risk with Nintendo's complete badass policy, I wonder how some publishers like Activision who released only terrible games did to survive (and why Nintendo put their seal of quality on it). Also no wonder why most developpers moved to the Play Station when it was released :p

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PostPosted: Fri Sep 04, 2009 4:09 am 
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Memblers wrote:
Also regarding the cost to publishers, the impression I got from reading some interviews was that Nintendo actually made their publishers pay up-front to produce a pretty large minimum number of carts. So publishers were taking a risk, while Nintendo was set to make money even if the carts were scrapped. No wonder Nintendo was so successful, and Atari/Tengen was so eager to set out on their own making unlicensed carts.


Yep, spot on.


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PostPosted: Fri Sep 04, 2009 6:42 am 
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This is one tactic I didn't like from nintendo (buying a lot of carts). But now that the DS still "print money", I wouldn't be surprised that they're still using that tactic...

Another fact was that you had to make your game exclusive for the nes. Today, no publisher would bend backward for such a request.


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PostPosted: Fri Sep 04, 2009 7:46 am 
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Another fact was that you had to make your game exclusive for the nes.

Not at all (so many NES games were also released on MSX, C64, arcade or whathever). It was arround the N64 area that Nintendo did force developpers to make it exculsive for the N64, and that policy completely failed as all developpers moved to Sony, Sega or PC machines so few gamers bough N64, and it's at that time Nintendo got the reputation to childish stuff they still have today : All serious developpers doing more mature games moved to other systems. So Nintendo stopped that policy after a while I guess.

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PostPosted: Fri Sep 04, 2009 7:56 am 
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Bregalad wrote:
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Another fact was that you had to make your game exclusive for the nes.

Not at all (so many NES games were also released on MSX, C64, arcade or whathever).

But you didn't see a lot of NES+SMS releases or NES+TG16 releases.


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PostPosted: Fri Sep 04, 2009 8:52 am 
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And yeah that Years Behind demo is beyond awesome if someone could provide the sourcecode of it it would be great.


Ok, here goes. But keep in mind the source code was never designed for readability, and viewing it will obviously spoil all three easter eggs contained in it. :)

http://www.student.itn.liu.se/~miciw347/YEARSB.ZIP


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PostPosted: Fri Sep 04, 2009 10:06 am 
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Oh thanks. I guess I found 2 of them :p
Would never have a clue of them, clever references to NES games.

What amazes me the most is how the logo shows up in the intro and how the yellow letters in the "Credits" looks like mode 7 on the NES.

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PostPosted: Fri Sep 04, 2009 4:20 pm 
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Thanks for letting me know. I sure spent far too many late nights polishing those two visual effects. :)

Speaking of devkits, I don't think I ever would have been able to finish Years Behind had I not built my glitchy-but-lovely EPROM emulator together with a friend of mine. Shifting the timing of register writes would have taken ages if I would have had to use a programmer or a CF card every time I assembled the code.

But I think a formidable alternative for the Powerpak could be done with Membler's RS232 to joypad cable, along with a patched boot ROM.


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PostPosted: Fri Sep 04, 2009 6:28 pm 
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Bregalad wrote:
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Another fact was that you had to make your game exclusive for the nes.

Not at all (so many NES games were also released on MSX, C64, arcade or whathever). It was arround the N64 area that Nintendo did force developpers to make it exculsive for the N64, and that policy completely failed as all developpers moved to Sony, Sega or PC machines so few gamers bough N64, and it's at that time Nintendo got the reputation to childish stuff they still have today : All serious developpers doing more mature games moved to other systems. So Nintendo stopped that policy after a while I guess.


You're getting your facts a bit wrong. For one, game (arcade conversion, Tetris, etc.) licenses were negotiated separately between console and home computer (hence MSX, C64) versions, and often by different companies.

Second, Nintendo's licensing agreement dictated, as far as I have seen it written many times, that licenses could not release the same game on a competing system for at least 2 years after its NES release. Nintendo loosened this policy around the SNES era (1991 or so...)

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PostPosted: Sat Sep 05, 2009 1:34 am 
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Mmh that's weird I was sure they forced N64 games to be exclusive. Maybe they went back on that policy and cancelled it again ? Well it's weird anyways.


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Speaking of devkits, I don't think I ever would have been able to finish Years Behind had I not built my glitchy-but-lovely EPROM emulator together with a friend of mine. Shifting the timing of register writes would have taken ages if I would have had to use a programmer or a CF card every time I assembled the code.

Sure, so immagine how even slower it was to compile code under a really old PC before having to programm your EPROMs slowly and test it on real hardware.

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PostPosted: Sat Sep 05, 2009 12:07 pm 
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Bregalad wrote:
Mmh that's weird I was sure they forced N64 games to be exclusive.

Hardly. See Forsaken 64 vs. Forsaken for PlayStation. But I seem to remember console makers giving discounts for exclusive or timed-exclusive titles, though the standard timed-exclusive period is down to about six months.


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PostPosted: Sat Sep 05, 2009 2:29 pm 
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There are many other games that were released on both the N64 and the Playstation, even if the ones on the Nintendo console would have different names ending in "64".


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PostPosted: Sat Sep 05, 2009 5:12 pm 
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Look at the Sega Genesis/Megadrive for example, my friend had one when it came out and we'd rent games regularly. It seemed like for a long time there weren't any 3rd party games at all. Everything was by Sega, or EA (unlicensed). Until Street Fighter 2 and Mortal Kombat, it seemed like there were virtually no identical games for both systems that I could notice.

I bet Nintendo was quite fearful of the TG16/PCE, as it's so similar to the NES I bet that a lot of developers would've had a very easy time porting their stuff to it.


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PostPosted: Sat Sep 05, 2009 5:50 pm 
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Memblers wrote:
I bet Nintendo was quite fearful of the TG16/PCE, as it's so similar to the NES I bet that a lot of developers would've had a very easy time porting their stuff to it.


For a while, the PCE was more successful than the famicom (in japan). So my bet is they made sure that it would not happen in the US by the exclusivity thing.. They have been quite aggressive in the US for that.


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