PPCenter :: devblog

PPcenter. Arts and craft for my Sega Saturn. Since 1847 :D

X-Terminator Cartridge Revival

Written by cafealpha 3 comments
This article is not about my own development experience, but from my friend XRider. Thanks a lot to him for the good work and the permission to share his pictures

First, what is a X-Terminator cartridge ? It is a Saturn flash cartridge which provides the following features :
 - 1MB expansion RAM
 - Backup memory
 - Ability to play import games
 - Cheat codes
 - Ability to search cheat codes by using standalone "X-Assist" unit


X-Terminator cartridge and X-Assist
Image taken from SegaRetro

X-Assist is particularly convenient because unlike Action Replay cartridges, it doesn't requires connection to a PC : it is true that connection to a PC provides more features (such as memory access, program upload, etc), but as "connection to PC" basically means "software support will be dropped someday", a standalone unit is a real treasure
For example, do you remember that Action Replay cartridges initially had DB25 connector ? This was for connecting the cartridge to PC via the -sold separately- Comms Link board, whose used now obsolete ISA port, and consequently not supported on nowadays PCs and/or OS.
There are some alternate solutions for connecting Action Replay to PC, whose major one is USB Data Link, but unfortunately it doesn't provides any software support for advanced features such as cheat codes search and testing.
So if you want to search cheat codes for your favorite game, X-Terminator is a good choice ! ... Okay, the user interface is in Japanese, but that's just a detail : after 200 or 300 hours learning about it, it shouldn't cause any problems

On the other hands, the major limitations are probably the lack of 4MB expansion RAM support, and using flash ROM for storing backup save data (which on the long term may brick the cartridge), but for a cartridge developed more than 20 years ago, theses limitations are quite honorable


So, once upon a time, XRider found a X-Terminator cartridge. It was a cheap auction, but on the other hand the cartridge didn't boot anymore, and the X-Assist unit wasn't included

Normal people would add this cartridge to their collection or put it on display as a decorating vintage objet Other people with engineering and electronics education background would put it on their "to repair someday" cardboard, and don't touch it for the next 20 years because they are busy with other projects or work, or real life, or all of theses at once

But XRider is none of them. XRider owns soldering tools. And knows how to use them. And really wants to fix this marvelous cartridge

So, let's try to fix the cartridge ! The first step would be to start with the most common problem, which is broken flash ROM.
In my opinion, this is the most difficult step, because it requires to desolder two chips for a total of 64 pins !
I personally can't do this because of lack of appropriate tools, so the alternate desoldering way I would had used would be to ... use a nipper and cut each pins

Fortunately, XRider likes work well done, so theses chips were removed in a clean way


X-Terminator cartridge, with flash ROM chips removed.
Additionally, all capacitors are removed too : that's
the occasion or never to replace them

Next step is a bit optional, and is about to dump removed flash ROM chips with flash ROM dumper device. This is the best way to verify if failure is due to corrupted flash ROM chips, and if still in working condition, this at least would be an occasion to dump the cartridge's firmware


Flash ROM chip on dumper device.

Dump is full of 0xFF bytes ... unless a miracle happens, theses flash ROM chips are no longer functioning  But, this comforts us regarding initial supposition of broken flash ROM chips causing cartridge not booting
 
Just in case of, let's verify PCB traces around flash ROM chips while theses are removed : this takes only 5 minutes to check, and it would be frustrating to find that cartridge was not working because of broken trace after soldering new flash ROM chips


PCB traces : just requires a light source
strong enough to be seen


What to do next ? Maybe use PLCC sockets so that future replacement of flash ROM chips would be easier ! That's a couple of weeks to wait for the postman, but worth the wait
PCB with PLCC32 sockets soldered

And then, simply replace the flash ROM chips

Next generation is here !


PCB with new flash ROM chips.
Additionally, new capacitors are populated


One last step remaining ! Flash ROM is mounted, but ROM itself needs to be set up with X-Terminator firmware. The simplest way to do this is to use Pseudo Saturn Kai flasher utility : it obviously allows to install Pseudo Saturn Kai, but also several other legacy firmwares in the case someone would want to revert to initial firmware after trying Pseudo Saturn Kai.


Just select the ROM version you want to install,
and follow on-screen instructions

 
Flashing in progress ! Will it work after that ?!


Yeehaw !!! It boot fine, mission done
Let's try with Metal Slug ...

Metal Slug works too !
So it seems there's no need to replace RAM chips


Everything finished ? No, there is a side quest remaining Among the couple of X-Terminator cartridges XRider owns, one X-Assist (pad and LCD unit used to search cheat codes) is missing.
One X-Assist available ? And another one missing ? No problem : let's reverse engineer the first one and DIY the second one

The X-Assist features two PCBs : one for connection interfacing and pad, and another one for LCD, as pictured below.

X-Assist pad/interfacing board

X-Assist LCD board

The LCD board is incredibly complex, but since it was manufactured as a whole and can still be purchased on auctions or second-hand market nowadays, there's no real interest to build it from scratch ! And I personally wouldn't try : that seems too much complex

So remaining is pad and interfacing board : fortunately it uses standard components and not any Gate Array Logic-ish components that would need to be reverse-engineered too. Simply speaking, it's like assembling LEGOs
Multi-meter, a LCD board, electronic breadboard, a bunch of wires, few electronic components ... is there something missing ? Yes ! A LOT of motivation !!


X-Assist DIY prototype, in all its glory


It's so beautiful it deserves another picture !

Let's try for real ! Of course, after verifying any eventual short-circuit with a multi-meter 
No short-circuit ? It's then ready for the "first-lighting ceremony" (火入れ式), as it is nicknamed in my neighboring ... I don't know if that's a common expression in Japan or anywhere else, but I like its naming anyway


No sparks ? No smoke ? That looks good

At first glance, that seems working ! Let's try cheat codes search feature in order to be 100% sure ...

Search unit not found ?!

Arg, it was too early to sing victory X-Assist seems not being correctly detected by X-Terminator cartridge ...
Since text could be sent to the LCD, let's assume nearly everything is working correctly, and that a small detail is causing this trouble ... after some head-scratching, XRider found what's wrong : a Zener diode that initially looked useless was used to return some ACK to X-Terminator cartridge when looking for its connection !


The X-Assist screen after adding the Zener diode :
code search memory could be captured !


65535 candidate codes ?! I'm not sure if correct cheat code could be found this time, but at least the DIY X-Assist unit works correctly now

 

Additional informations are available in French  on Darius forums :


Credits :
 - XRider, for the good work in game cartridges preservation
 - Darius, for gathering French community around Saturn

Read more X-Terminator Cartridge Revival

Back from Holidays

Written by cafealpha 2 comments
Just a small post to indicate I'm back from holidays
In fact, I went back home one week ago, but didn't had time to write this article so far ... but in comparison with other articles on this blog, this one is quite timely anyway


Hand Spinner ! 540 Yens ! 売れています!
It seems I took vacations to the last place in the world where
hard spinner are still popular


Pseudo Saturn Kai development is continuing at its own rhythm. Development finally escaped from off days without a lot of progress, and is now in the period when I want to hurry to finish "this and that features" before release. Let's hope that motivation will continue flowing, and also that work won't be too greedy with my free time too

I honestly have no idea when Pseudo Saturn Kai will be ready for release except than "when it's done" So, please be more patient until having fun with cheat codes !

Among other small things, I'm currently making some updates to the credits page. Because a careless mistake until version 6.074, credits page was available only in Pseudo Saturn Kai full version, hence this will be the debut for it on next release for Action Replay users

Read more Back from Holidays

Gamer's Cartridge available back soon !

Written by cafealpha no comments
A small article to keep informed about Gamer's Cartridge availability

So, I recently went out of Dezaemon 2 themed labels. Because being game-specific, I was expecting theses labels popular only for a niche of users, and prepared stocks accordingly, but theses actually became the main choice among the few labels available for Gamer's Cartridge, without letting me time to prepare extra stock for them

Okay, I admit I didn't checked actively the stock of theses labels, and started to panic when I saw that only 1 or 2 were remaining Additionally, I didn't had a lot of time during Spring holidays too ... March is always a busy month in Japan


Next batch of Dezaemon 2 labels is currently in preparation, so please be patient until they become available
I don't prepare theses labels by myself for the simple reason that my friend Darius cut them way better than me (1), so some extra delay is required for shipping. But basically theses will be available on the second half of this month

(1) And also because my printer is barely good enough to prepare new year postcards, and jam when processing A4 paper There's also some know-how required to prepare theses labels, such as selection of paper (it is using paper designed for use on car body), as well as cutting process too, as detailed in an previous article. Without Darius, labels for Gamer's Cartridge wouldn't exist


Dezaemon 2 labels for Gamer's Cartridge
Design by Mr beebaraka, and printing/cutting by Darius.
That's probably the component I'm the least involved in,
which explains why it's the most fancy one



On a less positive note, I am in the regret to announce that I'm out of stock of black shells, and that theses are no longer available for purchase

White Saturns have their plastics fading in several tones from "pure white as on first day" to "heavy smoker's dirty yellow", making difficult to adjust color difference between Saturn body and cartridge. Black Saturns doesn't have this plastic fade problem, which was the main reason why I was providing black cartridge shells

As I'm re-using Action Replay cartridge shells for Gamer's Cartridge, and that standard color for them is white, it's very unlikely I will get black shells in the future. But anyway, that doesn't stops availability of Gamer's Cartridge itself


Black cartridges out of production !
But white ones are still available from time to time

Read more Gamer's Cartridge available back soon !

Cheat codes overlap check feature

Written by cafealpha 4 comments
"Overlap check" ... yeah, I know that I'm always terrible when finding a name for a new feature or a new project

So, as its name may suggest, this feature check for cheat codes that would not work correctly together, and automatically unselect some cheat(s) in order to get things working as expected.
One illustration would be level select cheat code : some games may have a list of cheats like "play level 2", "play level 3", "play level 4", and so on. (no, there is usually no cheat code to play level 1 )

Example with Sonic 3D blast cheat codes : it's no longer
possible to simultaneously enable several "Play xyz level" codes
thanks to this overlap check feature


When trying cheat codes for the first time, the reflex would be "enable them all !", and in that case this would lead to undefined behavior. In typical case, game just work fine and since cheat codes are executed in the order from their list, the last overlapping cheat takes priority.

But, some games are quite picky regarding execution time, so the faster cheat codes handler is executed, the better. In other words, the less codes enabled, the more chances game have to work correctly.
Here is one example in video with NiGHTs into dreams : first half of the video shows cheat codes causing graphic glitches, and second half show updated Pseudo Saturn Kai version fixing theses glitches :


 
NiGHTs into dreams : graphic glitches caused by
cheat codes slow handler.
Video available on youtube.
Left : slow cheat codes handler, causing missing quads on screen
Right : game as well as unlimited time cheat code working fine

Hrm, that's around half a year ago, and I'm still fixing things for the same main feature  Well, that's how software development works : fixing bugs, adding new bugs, and returning back to step zero. Maybe smart people can develop things faster, but ... I'm not smart, so the best solution is to continue the endless development iterations until getting something OK for release


Illustration of Pseudo Saturn Kai development
(From The Crimson Permanent Insurance movie)

So well, let's go back to original topic, and let's add that I also felt bad each time I was enabling two incompatible codes. "Play level 2" : enable, "Play level 3" : enable, start game ... what will it do ? Maybe a thermonuclear meltdown because of some divide by zero error  ?! Well, it actually plays level 3, but that's unpleasant anyway.
I implemented cheat codes features from (basically) scratch first for fun (yes, I like 6+ months span software development projects ! ), but also for the freedom of making what I want. Especially, making cheat codes as user-friendly as possible ! So that this "overlap check" feature was added

Here is another example with cheat codes for Virtua Fighter Kids : this is an interesting example because some cheat codes for this game are using "enable code" (starting with `D') : this kind of code is sometimes used to prevent from executing other codes, typically when game module to cheat is not yet loaded, and that writing something to its location would make the game not working correctly.
As a consequence, "enable code" have a global effect on all enabled cheats, hence multiple "enable code" can't be enabled simultaneously.

Virtua Fighter kids uses "enable code" for a slightly different purpose : setting player health to a given value (50% of maximum, one HP, etc) only when it is set to maximum, ie on fight start time. By using this trick, game can then decrease health value, allowing to set some handicap to a given player.
This behavior is completely different in comparison to "unlimited health" cheat that always forces health value to maximum

Virtua Fighter Kids cheat codes list : "50% healt" and
"1-Hit Death" codes are the ones using enable codes


And, Virtua Fighter Kids is a good example, because it uses "enable code" at two different locations : at player 1 health value (06045974) and player 2 health value (06046A74). As only one "enable code" can be used, it's for example not possible to enable "1-hit death" code for both players.


Left : 1-Hit Death code enabled for P1
Right : P1 1-Hit Death code automatically disabled after
1-Hit Death code for P2 is enabled

Additionally, unlimited health for P2 is also automatically disabled, which is normal because it is in contradiction with 1-hit death code for it. From cheat code point of view, theses two codes write to same address, which doesn't makes sense.

"Hey, but I like "One Punch Man" series, and really want to enable theses two 1-hit death codes when playing Virtua Fighter Kids !" would you say ?
Well, that's not possible as-is, but adding a new cheat code setting both players health to 1 when health of any player is set to max value should do the job ♪
I didn't verified this code for real (in fact, I thought about it when writing this article), but it should be OK : "trust me, I'm an engineer"

1-Hit Death code for both P1 and P2
This could also be named "Two gentlemen duel"




I would like to finish this article with the introduction of a bug I fixed recently : I usually don't spend time in speaking about bugs I fix, because this would take too much time But the behavior of this one is very unexpected :

Text display is suddenly uncentered !?
Never though though such goofy bug
would be possible


So, this bug is triggered when selecting item in menu with scrolling text, and when text starts to scroll. The two features in relation with this bug (text centering and scrolling) are apparently unrelated, but the menu module used by Pseudo Saturn Kai is so spaghetti-ish that theses two features can collide into a bug

I'm honestly proud of this menu module It was initially designed for simple menu without even vertical scrolling, but evolved little by little in order to support each new features added to Pseudo Saturn Kai.
It's a complete spaghetti monster, but it works ! Yes, it works : trust me, I'm an engineer !

Read more Cheat codes overlap check feature

One more new PCB color !

Written by cafealpha no comments
As indicated in the title, I tried a new PCB color ! This time, this is yellow


Rare picture where all PCB colors I tried so far are gathered

The manufacturing of theses yellow PCBs took a bit longer than usual : maybe was it because this color is not ordered frequently ? Or just a bad luck with timings ? I don't know, but anyway I'm definitely more at ease with good old green color

Blue PCB in the picture above also needs some attention because it's quite a long time I didn't soldered PCBs with such color. In fact, it was probably the first time for this Gamer's Cartridge PCB revision

So, what's the reason why this article is posted so early ? I mean, pictures of theses PCBs were taken around one month ago, while preparation for one article here is usually in the half a year range, with majority of articles are canceled in the midway of their preparation  Well, the reason comes from accidentally watching TV recently, and realizing that colors match a given pattern !


Gamer's Cartridge, Olympic Games Edition

That would had be the the occasion to do some fancy "Gamer's Cartridge Olympic Games (C) (R) TM Edition" advertisements on all major social networks, modifying prices during this period, make sponsorship with some whatever sportswear brands, but I don't like such kind of show business, and ... the fact PCB colors match those on the Olympic flag is a coincidence

So, I'm glad to introduce you Gamer's Cartridge at the Olympic Games colors ! There's no sponsorship, no changes in the prices, no super event (except this poor blog article), but Saturn projects are still my favorite hobby, which is the most important


PS : I unfortunately no longer have all PCB colors gathered in first picture of this article, so it's not possible the re-take a picture in same layout as Olympic flag.

PPS : there wasn't snowball fight Olympic discipline this time too Let's hope next edition will finally feature competition of a sport which I understand the rules

Read more One more new PCB color !

Rss feed of the articles