angrycat

DS Cart Pin Mappings

UPDATE: This post is somewhat deprecated and you should check the thread over at DSDev for the latest conclusions.

TauZero has molested his Metroid cart to bring you the potential pin mappings:

Starting from the left, pins facing you:
Pin 1   -> GND
Pin 2   -> pin 5 of ROM and pin 6 of the EE (EE CLK)
Pin 3   -> pin 17 of ROM
Pin 4   -> pin 44 of ROM
Pin 5   -> pin 42 of ROM
Pin 6   -> pin 1 of EE (EE CS)
Pin 7   -> GND
Pin 8   -> VCC
Pin 9   -> pin 18 of ROM
Pin 10 -> pin 19 of ROM
Pin 11 -> pin 20 of ROM
Pin 12 -> pin 21 of ROM
Pin 13 -> pin 24 of ROM
Pin 14 -> pin 25 of ROM
Pin 15 -> pin 26 of ROM and pin 2 of EE (EE DOUT)
Pin 16 -> pin 27 of ROM and pin 5 of EE (EE DIN)
Pin 17 -> GND

For more of his thoughts on what this means continue reading the DS Cart Pinout thread over at gbadev's DSDev forum.

DS/ARM9 Speculation

phantom-inker posted speculatory musings on the DS' core CPU, which is an ARM9E-S. Myself and others have responded with some thoughts. There's enough interesting banter that the topic is worth pointing out. The interesting questions (at least in my mind) are:

• What practical performance penalty (if any) will manifest itself as a result of the increased number of pipeline stages (5 instead of the ARM7's 3)?

• What will the ARM9's special "protected" mode be used for, and does it require an MMU? So far the concensus on the DS was that it doesn't have an MMU, and this makes sense (to me at least) for the reasons I pointed out in the thread, namely that when one thinks of an MMU, virtual memory immediately comes to mind.

Given that there is no need for multiple processes to be running on the DS (as there might be for other ARM9 devices such as phones or PDAs running Symbian or Palm OSes), and given that there is no storage device (since carts are more or less a range of addressable memory as was the case on the GBA), there probably is not a need for an MMU. But maybe the MMU is required for the memory masking that the "protected" mode provides?

I have other questions about the fact that the ARM9 is using the Harvard architecture by offering seperate caches for instructions (8KB) and data (4KB). The GBA used the ARM7 which sported the classic Von Neumann architecture, exposing a single cache for data and instructions.

UPDATE: phantom-ink clarifies the implementation of the DS' protected mode and confirms that the DS' ARM9E-S does not have an MMU.

Spreading the love

The general point was made (over at gbadev's DSDev forum), and well taken, that there are many minds at work behind the recent DS Wi-Fi hacking progress. The list of names is too long to list but let's just invert it to say its not only Darkain and gladius.

Moreover its becoming clear that there are those who have been making progress and not sharing the results, nor the tools (hw or sw) they are using. Its pretty typical of how these things work, but no less frustrating. The DS homebrew scene would be even further down the line if there were a more open attitude in play. In the end it shouldn't matter since eventually everything will be known and public domain. In the meantime, everybody keep hacking away.

DS Graphics Theories

phantom-inker has posted a nice roundup of speculation on the DS' graphics capabilities. The first take away I have is that 3D is definitely done via hardware. This seems to have been the conventional wisdeom ever since the DS register leaks, although recently I have seen several mentions of a possible software library that official development may be using (either linked at build-time or available in ROM on the DS). It's a scenario that I am doubtful of.

Obviously homebrew would be far better off with an all hardware scenario and I am inclined to place my money on said horse.

Darkain Slashdoted

Darkain gets Slashdoted right here for not only his packet dumping progress (like that alliteration?), but for his DS USB power cable project.

I know I failed to mention the latter in earlier posts, probably because it was less relevent to efforts of getting hombrew code running on the DS. That said, its a very nice hardware hack.

The upside to this is that there is likely to be more eyes and potentially more fingers hacking and coding towards DS homebrew. We're one week into the system's lifespan and things are looking pretty good considering where things were on day one.

Hold your horses!

I am getting loud feedback from friends on this "DS blog". Very cute, but this is not a DS blog or a DS site. I realize I have listed other topics in the tagline and I don't intend to ignore them. The topics will begin to splinter onto other subject matters very soon, it just happens that the DS is the more interesting item at the moment and I haven't had the time to give the attention to other areas.

I promise a series of probing posts on C++ by midnight Thursday morning (Dec 2nd), in particular on meta-programming and the STL. And even before that I will have a few sprinkled posts on gaming, 3D engines and baseball AI. Do stay tuned ;)

Get an ARM up on things

A couple of friends have emailed to ask if there are any good books that would help in getting a leg up on deving for the DS. Well naturally there are no specific books on the topic, but given that the DS runs on the ARM9 (and the ARM7), it never hurts to get comfortable with the ARM family of processors and RISC computing in general. To help you gain that comfort I suggest you cozy up with a few books, they are the most authoritative references on ARM that I'm aware of.

• ARM System Developer's Guide : Designing and Optimizing System Software

• ARM System-on-Chip Architecture (2nd Edition)

As the tagline to this blog professes I will be blogging on the subject of RISC assembly in the very near future. If you're really eager to begin working your ARM chops, the Gameboy Advance runs on the ARM7tdmi and a good deal of its concepts and inner-workings will ready you for the DS when it becomes brewable.

Ports of call

I think I'll just continue to run with the 15th century sea-faring ambience as I blog DS hacking developments until I grow tired of it. With that said its getting crowded out there and its worth keeping a master list of sites that have an eye on or are involved with the DS hacking effort. I know there is a thread on the gbadev DSDev forum that is catching links of these sorts, but in the end it's easier to read a neat list then tread through a forum for links. Here you go, in no particular order:

• Darkain's DSDev page (dev & tech heavy)

• Darkain & Co.'s DS Live Journal page (dev and tech light)

• Dual-Scene (news/blog on DS Hacking progress)

• gladius' page (dev & tech heavy)

• The Mod Gods (news/blog on DS Hacking progress + DS gamer locator by zipcode)

• Warp Pipe forums (good general forums for discussing the networking aspect of the DS)

• gbadev's DSDev forum (probably discuss constructive DS hacking)

• Lik-Sang's internal DS photos
  

• The DS Dev Wiki  (a posting ground for established DS hacking facts)

• Darkfader's DS page  (great hacking info)

• WikiPedia's DS site  (lightweight but worth watching and good for an overview)

• Spicious' DS Wi-Fi hacking page (linux oriented)

I will be keeping this list up to date as time progresses, if only for my own purposes. Feel free to bookmark it as it will probably be exploding as DS homebrew becomes more of a reality. And in closing, thanks to all on these sites who have contributed to the effort so far.

Christopher "Darkain" Columbus?

The DS wireless hacking efforts continue to progress at a franetic pace and it's hard to deny that Darkain is turning out to be the chief explorer (with gladius as his XO?). I know I promised thorough narrative discussion on things as they progressed but I suggest you start off with the current crop of findings by heading over to Darkain's DS Wi-Fi Hacking page. You can also bring yourself up to speed on the steps that led it all by reading the verbose and yet still sometimes informative DS Wireless Cracking thread over at gbadev's DSDev forum and (you knew it wasn't all in one place right?) the thread entitled Tunneling Pictochat should be completely possible, plus...  over at Warppipe .

To be fair there are many other expeditions underway that are equally important, spicious has a page up on DS WiFi hacking using Linux. And don't forget gladius.

Ready, set, go!

Tomorrow morning marks one whole week since the launch of the Nintendo DS. The one question that has burned in my head every day since is "how long until it's hacked?" If you're like me you are anxiously working towards the ability to upload code and take control of this very unique and impressive piece of gaming hardware. One week may not seem like long but those who remember the early days of the Gameboy Advance homebrew scene will immediately recall the availability of a working emulator months prior to the system's release.  So why is it so different now?

Well for one thing the early GBA homebrew scene was aided by leaks and a much simpler system architecture. The DS has had little if any leaks of consequence and its architecture is definitely more complex. But that's not all, its clear right from the get go that Nintendo has put more energy and more forethought into combating piracy (inadvertently thwarting homebrew) at the hardware level at least, and maybe even the software level. If you had homebrew development on your mind when you bought your DS, the first thing you probably noticed was the little logo on the bottom of the box (and the DS itself) that reads "RSA Secured". Joy!

So what does all this mean? Where is DS hombrew one week later? The short answer is that its doing better than anyone might have thought just 3 or 4 days ago. Darkain has announced over at gbadev's DSDev forum  that he has intercepted a the complete Mario64 DS multiplayer ROM as it made its way from one DS to another via the system's wireless multi-boot. The best news? The ROM (targeted for the DS' ARM9 chip) is unencrypted!

There is a lot more detail to be considered with this latest milestone, and there are other tidbits that should be consumed in order to fully glean the direction of DS homebrew. Suffice it to say there are already several great resources online that have begun to signal news as it breaks. I will not try to replicate that, instead this site's DS coverage will be goaled towards providing a more thorough technical narrative on the latest breakthroughs and on the DS' hardware architecture in general. Anyone who has tried following the IRC channel, the forums and the numerous news sites will know that its not always easy to decipher the meaning and intent of everything out there. Hopefully you'll find this blog as a great resource for doing exactly that. Get ready for a fast paced week ahead. Week 2 should make Week 1 seem like time standing still.