It is currently Wed Jun 28, 2017 10:42 pm

All times are UTC - 7 hours



Forum rules


Related:



Post new topic Reply to topic  [ 54 posts ]  Go to page Previous  1, 2, 3, 4  Next
Author Message
PostPosted: Sun May 07, 2017 3:56 am 
Offline

Joined: Tue Feb 07, 2017 2:03 am
Posts: 180
Sure but can you get a CD "Cart" with an ARM-CortexM[something] and a cheap external USB based DVD drive + some RAM and the BIOS + SRAM is in the EEPROM/FLASH of the ARM? (Side note could maybe also be reworked as a new 1541 and a new FDS type system...hmmm )

Having MSU-1 as a platform is also nice, going "Sonic and Knuckles"/"Action Replay 3" with it would help with costs as it could also host the CIC, but you still have a Expensive Cart to put on top for the hardware users and then a download ROM for the emulators.

I will wager that the majority of users these days, the great unwashed as it were, as using Emulators, to which they put the CD into the tray and boot the emulator. Or add a USB DVD drive to their Retro Pi set-up et al. If the adapter above is feasible, then you have a cheap physical product that both Emulator and Hardware user can use. At the moment you have expensive carts for the users with hardware and "oh well its just another ROM, I will download it with the other 2000" emulator users.


Top
 Profile  
 
PostPosted: Sun May 07, 2017 10:49 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 5850
Location: Seattle
The problem with the notion of aping the SNES CDROM unit is that: even though it technically already exists, it exists in such small numbers that it's effectively a creation from scratch. It'd be a complete recapitulation of the SegaCD market fragmentation without the benefit of being commercially relevant. And in terms of engineering effort, translating between any modern bus (SATA, USB, whatever) and the SNES's parallel bus is going to make it expensive and stupidly designed.

As a design, it's awful; the PCEngine CD and SegaCD both provide dramatically more RAM, helping compensate for the abysmal load rate of a 1xCDROM , while the prototype here provides such a minuscule amount that there's basically no good way to do background loading. Any game designed for this is going to feel like an awkward multicart separated with lots of redbook audio.

You're never going to get anything like the current market for homebrew SegaCD games on the SNES. It's just too rarefied to be relevant.


Top
 Profile  
 
PostPosted: Sun May 07, 2017 11:25 am 
Offline
User avatar

Joined: Mon Sep 15, 2014 4:35 pm
Posts: 3016
Location: Nacogdoches, Texas
lidnariq wrote:
As a design, it's awful; the PCEngine CD and SegaCD both provide dramatically more RAM, helping compensate for the abysmal load rate of a 1xCDROM , while the prototype here provides such a minuscule amount that there's basically no good way to do background loading.

Even if the RAM were megabytes or the transfer rate was FastROM, what's the point? The Sega CD and PCEngine CD actually exist (one unit available to almost no one really doesn't count) and in the case of the Sega CD, actually provide a benefit outside of storage. This is just like setting arbitrary limits for yourself.

With that kind of storage, it makes me wonder if games were meant to be primarily cartridge-based but have the CD for audio and maybe some other data like title screen graphics. I don't really see the point there though; CDs are meant to be a cost effective measure, but that wouldn't matter if you had to have a cartridge anyway (although the cartridges could be smaller).


Top
 Profile  
 
PostPosted: Sun May 07, 2017 11:57 am 
Offline
Formerly WheelInventor

Joined: Thu Apr 14, 2016 2:55 am
Posts: 530
Location: Gothenburg, Sweden
RPG:s and the like could've benefited from having lots of recorded dialogues and phrases.

_________________
http://www.frankengraphics.com - personal NES blog


Top
 Profile  
 
PostPosted: Sun May 07, 2017 12:44 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 5850
Location: Seattle
Audio CDs only support a seek precision of 1 second and a 1x drive takes about a second to do the seek. So you really want to cache the audio in order to have any finer-grained control of when things play. But with only 256 (cart)+(128+64+64) total KiB of RAM in the entire system you can't really spare any significant amount of RAM for this.

In fact, that seek latency, combined with the tiny amount of RAM, makes it even worse; at 1x CDROM speeds you can fill the entire cart RAM in just 2.5 seconds. But it never gets much faster: for any size of load it's always going to be around 1.5-2 seconds.

As presented it'd be good for things you can stream from disc without pausing, e.g. soundtracks and cinematics (including yes, voice acting, but not anything that is responsive to the player), and that's really about it.


Top
 Profile  
 
PostPosted: Sun May 07, 2017 3:55 pm 
Offline

Joined: Wed Nov 30, 2016 9:59 pm
Posts: 52
byuu wrote:

Quote:
The "right" thing to do with todays technology would be to build a FPGA SNES.


Why? Every person who's tried won't release their source.

And even if they did, how many people have FPGA boards and the knowledge to flash FPGA code onto them?


If the Analogue NT Mini can be made and support all the Famicom, NES accessories, a SNES version is not a stretch. jwdonal's at least half way there with VeriSNES. The SNES is a far more enticing target to reengineer, particularly since the SNES-CD represents a more capable version of the hardware that works with the existing cartridges. The problem is the cost.

What I'm getting at, is that if a FPGA SNES does show up at some point, having the MSU-1 and/or CD-ROM functionality built in makes the requirement to have an additional $250 accessory (another $35 FPGA) unnecessary.

Oziphantom wrote:
Sure but can you get a CD "Cart" with an ARM-CortexM[something] and a cheap external USB based DVD drive + some RAM and the BIOS + SRAM is in the EEPROM/FLASH of the ARM? (Side note could maybe also be reworked as a new 1541 and a new FDS type system...hmmm )


Don't even bother with USB-anything. I've never seen a software emulator actually able to use a real CD-ROM. This is because modern CD-ROM/DVD-ROM drives are CAV unless in redbook audio mode. Adding USB bridges, SATA, and so forth just makes this more of a pain. Once you add USB, you run down the rabbit hole of never ending incompatibilities/speeds/sizes/filesystems with USB external storage devices. At least a SD-card standardizes on something.

Like from a homebrew point of view, a SNES-CD "clone" using a micro-sd card or something offers the most direct approach without having to add another cartridge like the MSU-1. Being able to use original cartridges still allows using the SD2SNES regardless. A more involved project could implement the MSU-1, SA-1, SuperFX, Sufami Turbo, Super Gameboy, etc.

_________________
I come from the net. Through systems, peoples and cities to this place.


Top
 Profile  
 
PostPosted: Sun May 07, 2017 9:01 pm 
Offline

Joined: Wed May 19, 2010 6:12 pm
Posts: 2173
byuu wrote:
Quote:
Unless you're dealing with 3D rendering, I think there comes a point where increased CPU power won't improve the appearance of the game at all


Eventually you would switch from using the SNES PPU directly to using it like the MSU1 uses FMV, and you'd be capped at 240x144x256 colors@30fps. Given Breath of the Wild runs at 30fps, that's ... not really all that horrible a limitation. But it really begs the question of, "why?!", to the point that even "because I can" sounds incredulous.


I like what Yoshi's Island did, by incorporating Super FX effects into a standard sprite based game. If someone makes a Super FX game (or an SA-1 game) it's far more interesting to see it being mixed with stock hardware tricks than just a straight up buffer.


Top
 Profile  
 
PostPosted: Mon May 08, 2017 5:11 am 
Offline

Joined: Mon Mar 30, 2015 10:14 am
Posts: 171
Quote:
If someone makes a Super FX game (or an SA-1 game) it's far more interesting to see it being mixed with stock hardware tricks than just a straight up buffer.

I don't know if that count but there is a SMW mod which use the SA-1:
https://www.youtube.com/watch?v=spVwBD6NOVI
https://www.youtube.com/watch?v=L-Gexw5l7ps
https://www.youtube.com/watch?v=-OJ_lhc-KkU&t

You can see here all his videos here:
https://www.youtube.com/user/VitorSuper ... rld/videos


Top
 Profile  
 
PostPosted: Mon May 08, 2017 1:28 pm 
Offline

Joined: Mon Mar 27, 2006 5:23 pm
Posts: 1290
Quote:
Would it be possible or feasible to make a MSU-1 Game Genie style cartridge?


Yes, it would. Should work fine to add MSU1 to any flash cartridge or retail cart release. Won't work very well for old SNES copiers, but I think only koitsu still uses those today? Of course that was six years ago so maybe not even he does anymore.

Quote:
Actually the idea of combining a Game Genie concept and MSU-1 together would be really cool to use an original cartridge with patches to play CD quality audio.


It would be an absolute pipe dream, but I'd love if the MSU1 passthru device had user-upgradeable firmware on it, and you could add patches to it, so when you put Chrono Trigger US on there, it played it with orchestral audio. And when you switched to Super Metroid, it'd play its music instead.

But yeah, a pipe dream of a device. It would be easier for the passthru cart to just -be- a stealth flashcart that identified the inserted cart's game title and then streamed its own ROM copy like a flash cart would. You would just be wasting money on extra hardware and connectors just to add a thin air of legitimacy. And then people would put "patches" that turn the Super Mario kart into Super Metroid and ... yeah.

Quote:
But back to the ideas of making any CD-like SNES system today I think the MSU-1 as a standalone cartridge with bootstrap and some amount of RAM would be the most viable.


Yep, and it's already doable with the sd2snes today, and you can request 128KiB of SRAM.

Quote:
I don't know how expensive of a FPGA or other circuitry you'd need to implement the MSU-1


Yeah, that's a great question. It was super overkill on the sd2snes. You can even do MSU1 + other coprocessors at the same time.

If we released the board wiring and an FPGA program, I could even see the possibility of someone eventually doing a new SNES cart release with MSU1 built into it. We have gotten a few new SNES games in cart form recently.

Quote:
Having MSU-1 as a platform is also nice, going "Sonic and Knuckles"/"Action Replay 3" with it would help with costs as it could also host the CIC


And being honest, given the homebrew nature ... it could take a more "sane" media format for the game cards. Whether that's SD, or a USB HID device slot, or even just an IDE connector that's easier to buy mating adapters for the daughter boards.

The CIC could also be like ikari's and work for both NTSC and PAL regions.

Quote:
Any game designed for this is going to feel like an awkward multicart separated with lots of redbook audio.


Yep, it would just be an inferior PC Engine CD.

... and I'd still support it in a heartbeat if even one official game disc were there for it. Maybe even a really good tech demo.

But aboslutely zero official software for it? No thank you. I'd rather make up my own devices.

Quote:
You're never going to get anything like the current market for homebrew SegaCD games on the SNES. It's just too rarefied to be relevant.


That and the 68K is easy to program for, and you can write decently performing C code for it.

No SNES add-on is going to fully abstract you from having to deal with the base 65816 you have to use to talk to the PPUs, or the nasty SMP->DSP if you want to do sound effects.

Sega CD users can use Redbook audio plus PSG sound effects. They don't have to deal with the Z80 or the YM2612 if it's too complex for them.

Quote:
jwdonal's at least half way there with VeriSNES.


Does it matter since jwdonal is keeping all his work to himself?

It's his right to, but is it going to help us? Is it like binaries on Windows where he can just give out 'compiled' Verilog and others can then use it on various FPGAs of their choosing?


Top
 Profile  
 
PostPosted: Mon May 08, 2017 2:17 pm 
Offline
User avatar

Joined: Sun May 27, 2012 8:43 pm
Posts: 1269
byuu wrote:
It's his right to, but is it going to help us? Is it like binaries on Windows where he can just give out 'compiled' Verilog and others can then use it on various FPGAs of their choosing?


Somewhat. A bitstream is built for a specific FPGA (for example, a Cyclone II EP2C35F672), but the distribution path for that is similar to a compiled binary for an existing platform.


Top
 Profile  
 
PostPosted: Mon May 08, 2017 5:54 pm 
Offline
User avatar

Joined: Wed Dec 06, 2006 8:18 pm
Posts: 2784
byuu wrote:
Quote:
But back to the ideas of making any CD-like SNES system today I think the MSU-1 as a standalone cartridge with bootstrap and some amount of RAM would be the most viable.


Yep, and it's already doable with the sd2snes today, and you can request 128KiB of SRAM.


Yes but I'm talking about something that doesn't have a $200 cost of entry. Certainly a smaller/lower cost chip (fpga) could be used to make something much cheaper. You just need the MSU-1 functionality with a SD card, a small bootstrap and fair amount of RAM. No need to support Cx4, DSP, Super FX, etc. You'd have your massive 4GB data storage and CD quality audio tracks, and a reasonable buffer to load data into. Making something that's under $100 to do this would probably be enough to get the interest going. With SD2SNES, you're just going to make a cartridge game with CD audio and maybe FMV. All your backgrounds, animations, levels, etc you'll just put in your ROM. With a stand alone cartridge you'd be more incentivized to store it on the SD since that's cheaper storage than FlashROM.

Quote:
Quote:
Any game designed for this is going to feel like an awkward multicart separated with lots of redbook audio.


Yep, it would just be an inferior PC Engine CD.

... and I'd still support it in a heartbeat if even one official game disc were there for it. Maybe even a really good tech demo.

But aboslutely zero official software for it? No thank you. I'd rather make up my own devices.


The PC-Engine CD format did so well and being commercially supported for many years any homebrew SNES CD could never come close. But it would be interesting to see what could be done with the SNES and the CD format. It'd be really amusing to make an adapter to hookup a PCE CD-ROM to a SNES. But back to reality, the PC-Engine CD and even Sega CD are why the concept with the SNES is so interesting.

The MSU-1 paired with even just 1 megabyte of RAM could be used to great effect since MSU-1 has extremely fast access to that 4GB of data. With some slower media like CD-ROM I can see wanting more RAM. But I really think that's the closest we'll ever see to a SNES CD-ROM being used by homebrew developers. No one is going to make an actual CD-ROM system. Too expensive for just a homebrew toy.


Top
 Profile  
 
PostPosted: Mon May 08, 2017 7:47 pm 
Offline

Joined: Sun Sep 19, 2004 11:12 pm
Posts: 18539
Location: NE Indiana, USA (NTSC)
I think even MSU-1 might be overkill for some homebrew apps. How much would it cost to build a cart with a boot ROM, a 1 MB RAM, and a minimalist microSD interface?


Top
 Profile  
 
PostPosted: Mon May 08, 2017 8:27 pm 
Offline
User avatar

Joined: Wed Dec 06, 2006 8:18 pm
Posts: 2784
How minimalist? I think sticking with MSU-1 would be a good idea since it exists already. And CD quality audio is appealing not just for the quality but also the simplification to a developer when it comes to adding music. No need to put together a SPC module that handles both music and sound effects, just sound effects.

The Super EverDrive which is a solid Flash cartridge sells for around $86USD. While it's not a great comparison I think it gives you a ballpark figure for cost. You'd need to find out how much it'd cost for the SRAM or PSRAM you want to use as well as whatever programmable logic you need. Depending on component costs it might make sense to have more than 1 megabyte of RAM. How cheaply you could make it really depends on a lot of details that would need to be worked out. It might just end up looking like another flash cart. Ofcourse it would help such a device be more useful if it could load some ROMs by having RAM mapped to be compatible maybe with LoROM up to however much RAM is on board.


Top
 Profile  
 
PostPosted: Mon May 08, 2017 10:12 pm 
Offline

Joined: Fri Jul 04, 2014 9:31 pm
Posts: 725
Another thing about CD or MSU1 audio is that it greatly broadens the scope of what you can do with the sound effects, since you can use the system's full array of audio resources just for that.

I was considering this for the SA-1 F-Zero game I'm almost certainly never going to make, because it would allow more sophisticated sound effects, including multiple sounds from multiple nearby machines instead of just engine noise for one.


Top
 Profile  
 
PostPosted: Mon May 08, 2017 10:35 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 5850
Location: Seattle
Back-of-the-envelope calculation for "cheapest BOM I can think of with access to lots and lots of storage":
128KiB 5V BIOS ROM/@10 ≈ $1
128KiB 5V RAM/@10 ≈ $1.70
74'139 /@10 ≈ $0.30
CF socket /@10 ≈ $2.70
PCB /@10 ≈$1.5
CF card /@1 ≈ $10

→ CF design ≈ $17.2

128 KiB 3V BIOS ROM/@10 ≈ $0.80
128 KiB 3V RAM/@10 ≈ $1.60
3x 74'16244/@30 ≈ $0.50
iCE40LP384 (QFN32) /@10 ≈ $1.67
8 KiB SPI FPGA CFG ROM/@10 ≈ $0.30
microSD socket ≈ $0.70
PCB /@10 ≈ $1.5
SD card /@1 ≈ $6

→ SD design ≈ $13

... Huh. Well then.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 54 posts ]  Go to page Previous  1, 2, 3, 4  Next

All times are UTC - 7 hours


Who is online

Users browsing this forum: AWJ, UnDisbeliever and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group