JOTEGO

Quartet 2 & News

I started this week trying to get System 16B games working, but I came across the i8051 MCU again. This MCU is used in many arcade games, and I have already faced it in the past. There are no good open-source cores for it. At least, not good from our retro point of view. I haven't been able to make it work reliably so far.

Ace contacted me about a sprite issue in the Contra core, and by reviewing the implementation, we found that a latch was missing. That was added, and the files in JTB...

Alien Syndrome, Passing Shot, Time Scanner and CPS2

MiSTer users: copy beta.zip to games/mame

This week we have three classic titles. Passing Shot was my tennis school as a kid and Alien Syndrome was on magazine covers everywhere. And Time Scanner is one of the best-known pinball titles.

Note that for Passing Shot, you will have to look in the Alternatives folder. 

After this, we have almost covered all System16A games. There are three titles left that have odd controls. SDI, with a mix of analogue+joyst...

SEGA System 16 Hardware Variations

The SEGA System 16 isn't a single arcade game architecture. It had two major versions: 16A and 16B and a close ancestor known as pre 16A. But if you look closer, you will find more variations.

There were boards with unencrypted CPUs, but there were encrypted ones too. And among them, there were several options too: FD1089A, FD1089B (Action Fighter, Sukeban...) and FD1094 (some 16A games, 16B) for the M68000 code. Encryption worked by non-destructive bit transformations: permutations and...

The bug is fixed. Plus Tetris & Body Slam

The long story of the M68000 related bug finally came to a happy ending. Long story short, Blackwine identified the instruction that broke Shinobi and Ijor -the M68000 module author- suggested the read-modify-write cycle could be wrong in the glue logic.

Normally, a CPU takes control of the data bus to read or write, not both. However, the M68000 provides a special case for an atomic read-modify-write that doesn't release the bus in the meantime. Once the importance of this special cycl...

Time to release CPS2?

The CPS2 core still has several issues which are all likely linked to a bug in the M68000 CPU. I will eventually find and fix the bug, but it can still take from days to a few weeks.

If I release CPS2 as it is, there is a major problem with Mars Matrix and with Gigawing's final boss. 

I haven't been able to run the speed comparison tests yet, but that worries me less as it will be easy to correct once we have the speed test suite in place.

So I am not entirely happy abo...

Wonder Boy 3, Phantasy Zone and more!

Hi all, I have too many news this week!

-New System 16 beta with four games added: Wonder Boy 3, Phantasy Zone, Action  Fighter and Alex Kidd. Note that WB3 is in the alternatives folder only for now.

-For MiST and Sidi, just use the attached files as usual

-For MiSTer, beta files are now stored in jtbin and you can download them from there. Y...

Arcade Cheats

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Last week's I held a video meeting with the Patreon directors. To summarize it in a line, I want to increase the quality and quantity of the work. For this, I will try to leverage both the community and full time hires. I am about to make an offer to the first JT employee to work full time on development. At the same time, I bring today a new tool that should enable more community contributions: a cheat engine.

There are hundreds of documented arcade cheats availa...

CPS2 Final Beta

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We finally close the CPS2 beta series this week with four titles:

1. Hyper SF2 Anniversary Edition
2. Armored Warriors
3. Gigawing
4. Mars Matrix

I am very thankful to all of you for supporting the development of this core. However, I must say that it is still not perfect. A bug makes Mars Matrix run at a crazy speed and breaks Gigawing final boss logic. I still haven't run the PCB speed checks eit...

Labyrinth Runner (Trick’n Trap)

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I have given a big push to the Konami titles this week. I have applied many of Furrtek's discoveries on the custom chips. As a result, many graphic glitches have gone away in Combat School and Labyrinth Runner. In addition, the custom chip involved in the barrel calculation (Contra 3D phases) is now part of the core too, so barrels now fall within their lanes.

With all these impro...

Super Street Fighter 2 Support

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This week's update comes with a ton of internal changes. First, the SDRAM is now operated at bursts of 8 bytes, so graphics information is transferred in a single request. Together with other improvements, this change has boosted the number of sprites per line, and the X-Men COTA start screen is now correctly displayed.

I was misreading a part of the schematics related to bus timing. That is corrected too, so you may feel a speed up.

The start point for rast...

Marvel vs CAPCOM and Vampire Savior 2

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I had fixed, improved and strengthen many core features not just during the week but during the last two weeks. So, I was looking forward to this update. But, in the tests before bringing this to you, I found a couple of graphics issues that could also be hiding elsewhere. I didn't even get to pass the final files to the JTAlpha team for testing. I had to make the painful decision of rolling back to a safe place.

Therefore, this week's core is internally very simi...

Marvel Heroes and Cyberbots

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This has been another busy week of catching bugs, trying to close the core development. There are four types of problems left:

1. Graphic glitches due to SDRAM congestion

2. Raster and row scrolling effects not working well together

3. Odd behaviours that could point to a bug in the M68000 CPU module

4. Rendering of a wrong tile in some specific scenes

I have re-written the SDRAM controller to make it more flexible and squeeze a bit more pe...

X-Men vs SF, Vampire Savior, Super Gem Fighter and Slam Masters 2

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It has been a very intense week as I am ironing out the little things pending in the core. They are little, but they are the toughest ones!

The only worrying one is Gigawing because, in a couple of scenes, there is a moment when the SDRAM fails to deliver all the sprites, and some lines show glitches.

As some people reported that Progear was too slow, I have disabled the CPS-A chip DMA. This will speed up the game a bit. I don't plan to measure that DMA sign...

Progear & Eco Fighters

You were expecting more shooters, and here you go:

-Progear: this game has awesome graphics. It reminds me of Studio Ghibli art. The gameplay is also great.

-Eco Fighters: this horizontal shooter has an interesting mechanic because of the rotating cannon, similar to Forgotten Worlds. The Megaman team designed it.

I will catch with you next Friday!

Español

Esperabas más tiradores, y aquí las tienes:

-Progear: este juego tiene unos gráfic...

The Speed Rumbler

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I started on Patreon 2 years ago, after my Ghosts'n Goblins core was ported to MiSTer. When I saw the coverage that Smokemonster made for it on his YT channel, I thought it was worth developing more systems. Two years later, I have published a ton of stuff: individual chip modules, single arcade boards and multi-game arcades. And all this has been possible because of your continuous support. This week we hit the 2000 patron count. It is an incredible milestone that just...

Poll: next CPS2 update

What would you like the next JTFriday to be about?

SFA3, D&D Mystara, 1944 and Choko!

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We finish three series of games this week:

-Dungeon&Dragons, by adding Shadow over Mystara
-19XX, by adding 1944
-Street Fighter Alpha, by adding the third game

Plus Janpai Puzzle Choko, a title in Japanese, but you don't need to understand the language to play. Give it a go!

Grego2d has made a special MRA for SFA3 that patches the game with a hack he and rotwang ...

Shinobi

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I've been working non-stop to find the bug in the QSound chip producing the distortion, but I still haven't got it. So there is no CPS2 update this week. 

To make up for it, and because I know some people miss 80's games, I am offering you one of my personal favourites this week: Shinobi.

By the way, I want to thank FunkyCochise and AMoore2600 for lending me their System 16/18 boards to work on this.

KNOWN BUG: IF YOU WIN...