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

I wanted to publish an article this October ...

Written by cafealpha no comments
... and all of a sudden, November arrived

It's not like being under a quota of articles to write every months would stop the financing of my Saturn projects and in fact, as described on my "donate" page or this blog article, I don't have any interest in crowdfunding, or some kind of third party financing : if I'm not in the mood, or don't have enough free time to update this blog, then I don't update it

But well, moreover not being paid for not writing blog articles, as I actually have to pay to keep this blog alive (web page hosting is cheap but not free, but at least it's my own homepage ), I like to feed this blog from time to time even when being busy with real life things
So don't worry, I didn't stopped this blog : currently, I have one ongoing article that is waiting for its last paragraph and proofreading etc, but as I started more than two weeks ago (yes, that's my usual pace when preparing blog articles), please be patient until I finish it
I do have some ideas for future articles too, but theses are just ideas currently recorded as single lines in my TODO list, so I don't know when I actually start writing them


Regarding Pseudo Saturn Kai project, I ... didn't had a lot of free time to continue it recently In fact, I think I just turned on my Saturn once last month just to test if -as requested by someone by email- DoDonPachi worked with Pseudo Saturn Kai or not. The game worked fine here, so I turned off my dev Saturn an put it back in my closet for better times when I will be more available
BTW, I'm currently experiencing an unexpected burst of things to do at work, so it may take a while until things return back to normal But as I can't live without doing my Saturn projects, I promise that things will return back to normal as soon as possible


... Well, the contents in this article are a bit poor, so let's fill remaining space with random facts about my life recently The "okra" plant I wrote about in a previous blog article is still going well and I continue to water it regularly.

Okra in all its glory, 2018/10/18

Since summer is now finished, I no longer have to water it everyday, so that I now just do this regularly enough to prevent it from finishing yellow and burned  And yes, the kid who took back that from school completely forgot about its existence
I'm not keen on gardening (as suggested on the picture above, I don't even own a garden), but have a couple of pictures of other green things in reserve ... and I keep theses to fill future small posts

Read more I wanted to publish an article this October ...

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

Year 2017 - Synthesis

Written by cafealpha no comments
Synthesis ... this is the kind of blog article posted at the end of December in normal blogs, but since this is not a normal blog, and that I can't respect any schedule for it, let's prepare this article at the beginning of January

Last year started well with an order of Gamer's Cartridge from IGK, who is administrator of Dezaemon DB homepage. More than administrating Dezaemon DB, he is also a dezaemoner who (among other titles) developed Biometal Nemesis, which deserves its youtube link in this blog :)
Biometal Nemesis - Click above if you like shmups

I really like the style of this Dezaemon game ! Thank you very much IGK for creating such gem

Thanks to IGK, it was possible to finish support of Saturn Floppy Disk Drive on Save Data Manager : initialization of this device is slightly different than with internal backup memory and backup memory cartridge, and consequently was causing troubles on various configurations such as no backup memory cartridge inserted, but floppy disk connected, etc. Fixing all possible patterns wouldn't had been possible without kind help and beta testing from IGK. Thank you


Save Data Manager (version around 2017/01/30)
Configuration when this screen was taken was no "backup memory cartridge inserted, and floppy disk connected", which was causing troubles because among other things, unavailable device in the middle of devices table wasn't supported.

Additionally, this was the occasion to add virtual floppy disk support on Gamer's Cartridge, making Saturn considering a floppy disk drive is available, even if not physically connected.
Main purpose of this feature is to add 5 more save and load slots in Dezaemon 2, which, in addition of the 5 slots on backup memory cartridge, makes possible to manage up to 10 saves into a Dezaemon 2 session directly from a single SD card 
I don't remember exactly what was the trigger which started the addition of this feature, but I think that a suggestion from IGK like "it would be cool if floppy disk would be supported by Gamer's Cartridge too" and me "Ah yeah, that's a nice idea ... how many save slots do you want ?"

After that, IGK continued to surprise me by asking his friend beebaraka to draw a Dezaemon 2 themed label for Gamer's Cartridge ... As a result, I received images for two labels, which I personally consider as the masterpieces among Gamer's Cartridge label collection
My preference goes to the white-themed label, but I suppose it's just a matter of personal taste.

Dezaemon 2 themed Gamer's Cartridges
Like shooting games ? Like DIY ? Theses cartridges are designed for you

In parallel of theses Dezaemon 2 adventures, generous contributors helped in dumping firmware of some exotic Saturn cartridges, and were successfully added to Pseudo Saturn Kai Save Data Manager.
Most relevant dumps were for X-Terminator cartridge, and Urawaza Dataro cartridge : first one is a cartridge with extended support for cheat codes, especially with extra controller allowing in-game search of cheat codes. Later one provides special save data for several (around 34 IIRC) Japanese games. Special thanks to Madrom for providing dump of this cartridge !

All the points below contributed to prepare the "20170423" release of Pseudo Saturn Kai. Warm thanks to all contributors who could make it possible !


Second half of the year mostly concerned cheat codes addition to Pseudo Saturn Kai. It started in June (or May ... I don't remember correctly) from a Gamer's Cartridge user asking when cheat codes will be available in Pseudo Saturn Kai ... this reminded me I still had to finish that until next release


First working version of cheat codes
hander, with USB transfer support
It's not visible on this picture, but many polygons weren't
drawn because of performance issues.

Unlimited time cheat code working : it took me around
one month to fix missing polygons, because of unoptimized
implementation of cheat codes handler), but I did it
 
Cheat codes kept me busy for six solid months, basically in understanding to manage cheat codes in a similar way as is it done on Action Replay firmware, optimizing critical code, importing codes list, finishing cheat codes related interface, testing several games, etc.
That's honestly a hard work, but this was also an occasion to add in-game USB transfer via USB dev cart. Thanks to this, the basis in order to fix or improve cheat codes is ready  Proper PC software for cheat codes detection is still missing, but hopefully this will be done someday.

Akumajo Dracula-X illustration with Maria's inifinite jump cheat code.
This game was a nasty one regarding cheat code support, with very
tight CPU and RAM left for cheat codes handler. This was an occasion
to develop many cheat codes debug features

Summer was also the occasion for me to officially end manufacturing and support of USB dev cart : after 5 years involved in this adventure, I considered it was enough, because :
 1. USB dev cart interests basically nobody
 2. In the rare cases USB dev cart interests somebody, it is usually used for closed-source projects
(But there are notable exceptions where USB dev cart contributed to Saturn open source projects. Big thanks to theses concerned peoples for making Saturn homebrew scene brighter )



I'm hesitating about the timing for next Pseudo Saturn Kai release : should I take some extra months in order to get proper cheat codes support for most popular games ? Or should I release it under few weeks with minimal cheat codes support (around an handful of games are currently tested and working), and hope to receive some feedback from users, so that I will eventually know which games need their cheat codes to be fixed ?

That's a very difficult choice : cheat codes is a niche feature (as everything else regarding Saturn !), so I shouldn't hope a lot of feedback. On the other hand, adding a cheat codes edition screen, and allowing cheat codes input on user side is (IMHO) a mistake too : maybe a motivated user would fix and/or add codes for some games, but rarely theses codes will be publicly available for everybody else, and in the other cases, user will simply consider Pseudo Saturn Kai cheat codes as a broken feature.
Let's see ... I honestly don't have any precise idea when next release should be done. Any suggestion regarding this is welcome in the comments

Generally speaking, I'm tired about Pseudo Saturn Kai maintenance : I started it around two years ago (yes, largely over than nine thousands hours !!!), edit: that was around three years ago (I though we were at the beginning of year 2017 ), am finally seeing the end of my TODO list to realize that ... majority of users shifted to hardware ODE, or simply left the scene without any last final word ...

Well, whatever it may be, I continue development of Pseudo Saturn Kai because I went too far to stop so near of the end (that's quite a pragmatic argument, sorry), but also (and that's the most important), because that's a nice hobby, which is important in order to keep a balance between private and work

Also, my first steps in Pseudo Saturn Kai maintenance were made during my hospitalization for cancer, and keeping such hobby during theses hard times was worth gold. I don't know (and don't want to know) how things would had turned without my Saturn hobbies.

BTW, things concerning my health are getting well : I'm still undergoing periodical screening, which all were OK last year  Last year was the celebration of 3 years all right after surgery, which is not bad for a cancer with 50-60% 5 years survival rate

Pokemon Go still not allowed in hospital.
Fortunately, usage Saturn dev laptop isn't forbidden



To finish this article on a rant note (sorry if you went here for some final positive note ), I would like to say "thank you for nothing" to Rhea/Phoebe development team rmenu author. (← updated on 2018/06/20)

Why ? Reason is that I would like to add a rmenu equivalent to Pseudo Saturn Kai, but don't have any technical information to implement it, and it's not like I didn't asked about theses informations, but simply didn't received any relevant reply from concerned developer(s).
For a semi-commercial product, I can understand to keep schematics, source codes and other development resources private. But I don't request disclosure of theses resources, and just want some minimal information for interoperability, which isn't publicly available, and that's a pity.

Why is that a pity ? Because some cheat codes will certainly not work by having rmenu running between Pseudo Saturn Kai and Saturn game. I know there's the solution to use rmenu's full boot, which does a system reset of nearly everything (except Rhea/Phoebe, obviously) after selecting a game, so that cheat codes can be enabled after that ... but I really don't know anybody motivated to do this messy setup : everybody is using the rmenu's quick boot solution, right ?


Pseudo Saturn Kai's rmenu, dated 20151214.
Latest version have some major improvements,  such as
scrolling title of select game, etc
Because of lack of Rhea/Phoebe API, this feature is disabled.


I'm personally (and honestly) not concerned about this problem : my modded Saturn + USB dev cart are enough for my development needs, and I don't want to pay for a device costing an arm and a leg (plus a kidney when buying from ebay ...) and then having to do the reverse-engineering job for it after that ! So unless I got external help, clean support for Rhea/Phoebe will be done ... without me

From what I could found from static analysis of rmenu itself, version is checked by seeking to the last available data sector of the CD track, and game is selected by seeking to sectors just before that last available one.
After that's it's difficult to guess what data should be expected from Rhea/Phoebe without testing on real hardware. And reverse-engineering is usually a sluggish and hard work (I estimate the remaining as around a two weeks course ... and hope this to be a pessimistic estimation), and really would like to spend this time to other projects funnier.

2018/06/20 update : there will be proper support of Rhea/Phoebe image selection in Pseudo Saturn Kai, and consequently an user-friendly way of enabling cheat codes when using theses ODE
Very big thanks to Deunan Knute for the great job, providing the technical informations and everything else
And also I would like to thank privateye for contacting Deunan, his patience and great help in beta testing

Read more Year 2017 - Synthesis

USB dev cart & SD card interface on a single cartridge

Written by cafealpha 1 comment
Last week, I populated the second "USB & SD card" dev cart ever

data/images/20160112_usb_sdcart.tb.jpg
USB & SD dev cart Rev 3.2

Why "second" ? Because the first "USB & SD card" dev cart I made is the one I'm currently using for dev :
data/images/20150716_memcart_rev2f.tb.jpg
USB & SD dev cart Rev 2f

PCB revision is different ... can you spot the differences ?

It can't be seen on the picture, but Rev 2f have a 128KB SRAM chip soldered on its rear side.
I actually don't use it, this is just a remain of the times I though extra RAM was required in order to get "SD Memory Cart" features to work.
After many tests, I could verify that it was not needed : SH-2 code for "SD Memory Cart" feature runs directly from Flash ROM, and 16KB+8KB of work RAM provided by games for Backup library is enough for my needs.
So I removed the routing for this SRAM chip on Rev 3.2 PCB

Another story, but about Rev 3.2 cartridge pictured in this article : I was about to trash it because I couldn't flash its CPLD firmware, and hence thought it was broken.
I first though that CPLD itself was broken (this may rarely happen when overheating it during soldering), so I removed it and soldered another CPLD, and ... same behavior
CPLD itself is detected by Quartus, but flash always fails at 98% of the flashing process. I (finally ) start to think it may be a power supply related problem, and ... bingo : CPLD wasn't 3.3V as expected.
In fact, this board features two 5V -> 3.3V power converter units (on PCB rear side, can't be seen on the picture above), a "spare" one not connected anywhere (just here in case of), and the "real" one, and I populated the "spare" one
In order to fix this, I didn't populated the "real" one, but instead connected the spare one to SD card and CPLD power supply line, and that's why there is a grey wire nearly USB connector



Final note : as I consider USB port for debug only, I don't plan to improve the architecture and routing of such "USB & SD dev cart", so I suppose its design will remain "messy and fat" for a while ...
But in the hypothetical case many talented developers will suddenly arrive in Saturn Homebrew scene and will want to develop games using both CD ROM for music and SD card for huge game data (yeah, I really want a Saturn game with gameplay/level/whatever data so large that it can't fit a CD-ROM !), I will re-design it in order everything fit in a standard cartridge shell

Read more USB dev cart & SD card interface on a single cartridge

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