JOTEGO

Analog Audio Circuitry

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Analog circuit design remains an enigmatic discipline that has, to date, evaded the expansive reach of ChatGPT and similar technologies. It's therefore not entirely surprising that analog circuits represent the most overlooked element of arcade PCBs (Printed Circuit Boards). Yet, digital-to-analog conversion is essential for producing video and audio output...

1942/1943 and Work on Audio Filters

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Arcade video games have three types of sound sources:

1. Square/triangular waveforms at different frequencies: PSG sound (1942, Exed Exes, Kicker, Track'n Field...)
2. Sine waves modulating other sine waves in frequency: FM sound (Street Fighter 2, Shinobi, Out Run...)
3. Digitised sounds: PCM sound (Drums in Out Run, the title song in ...
   2024-03-01 17:32:05 +0000 UTC View Post

Vendetta (Crime Fighters 2)

Last minute release today, please excuse us for the short  post: we've managed to get Vendetta working in the JTSIMSON core. The  hardware is extremely similar between the two systems, although they are  incompatible. You cannot just swap the ROM chips from one to the other  and get them working. The devices are mapped to different CPU addresses  and there are a couple ...

Parodius da!

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We worked on Parodius da! schematics last year. It turned out to be very similar to The Simpsons board, with some differences:

• Different sprite chipset: 053244/5 instead of 053246/7. This chipset  is very similar but only supports half the sprite count of the Simpsons one. Sprite scaling uses a different range and...
  2024-02-09 10:48:34 +0000 UTC View Post

Body Slam / Quartet / JTALIENS release

Thanks for the feedback on last week's service release.  Some regression errors were quickly identified by the community and  appropiate patches have been applied:

• Double Dragon 2 music stops
• Pop soun...
  2024-02-02 16:29:43 +0000 UTC View Post

Service Release

Thanks to everyone who has taken the time to report an issue in GitHub. All files have been updated in JTBIN. You can run your favourite MiSTer/Pocket updater or grab the files manually.

This service release tackles the following issues:<...

Global Core Review and Issue Solving

As most of you know, issues related to JTCORES are collected here.  This includes road map items, reverse engineering activity, core  enhancements and bug fixes. After the NeoGeo Pocket core release, I  decided to take some time to clear out the issue list as much as  possible. Other scene devel...

NeoGeo Pocket Beta Core

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Just in time for reyes,  the first beta core for NeoGeo Pocket is available for MiSTer and  Analogue Pocket in the usual locations. Sadly, this core does not fit in  smaller FPGAs, like SiDi or MiST because of internal RAM size  ...

NGP Development Update / 1942/Higemaru for Pocket

2023-12-29 NGP Development Update / 1942/Higemaru for Pocket

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NeoGeo Pocket Update

The NeoGeo Pocket core is the worst time to market from my career. I have worked on and off on it for the last two years.  During some months, it has been the main focus. I also tried to have  three different developers work on test tasks on ...

MCU Time! Bubble Bobble, Tokio, Renegade...

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When I made the JTBUBL (Bubble Bobble, Tokio) core, I had  to limit it to certain game versions that used a MCU (Micro Controller  Unit) for which I had found a Verilog module. That meant putting the  original Tokio version aside and working only with the bootleg. The same  happened with Renegade too, where I had to hide the MRA for the ...

Thunder Cross, Space Odyssey and Keyboard Support on the Pocket

Thunder Cross

JTALIENS core gets support for one more game: Thunder  Cross. This is a spectacular shooter with a good depth feeling thanks to  the use of parallax scrolling and sprite scaling. As in Nemesis, you  get options to fly along your ship. These options can either shoot with you or use a special shoot, depending on the po...

2023-11-17 Gang Busters and Public Releases

The JTALIENS core receives support for a new game added this week: Konami's Gang Busters.  This is a cute two-player game that reminds of Labyrinth Runner and  CAPCOM's Avengers. The cop duo of the diminutive Smith and the taller  Wesson (over the pistols Smith & Wesson), who can't help but shoot  when they have a gun, shoot, shoot, shoot to protect thei...

Unplayable? Only credits?

Unplayable?

If you see the core credits rolling through the screen but cannot play then:

1. If you cannot see the game attract mode behind the credits, then you are missing the game ROMs
2. If you can see the game running but cannot insert coins ...
   2023-11-07 14:42:38 +0000 UTC View Post

More Halloween Games

Today is Halloween so we are going to introduce five Halloween-ish games. All of them are playable on multiple FPGA platforms through JT cores. Try them out if you haven't already!

First up is Haunted Castle, released by Konami in 1988, a rare reimportation from a consumer console to an arcade game. The gothic horror worldview was further refined in the arcade version, wi...

Halloween special: Splatter House

Important: jtbeta.zip changed, you need to update your copy.

I used to believe in Christmas miracles, now I have to believe in Halloween miracles too! Just five days ago, the JTSHOUSE core was unplayable and with completely broken music. I thought that having this beta release was a long shot, but here we are.

The main difficulty, as I explained before, has been the...

FPGA Platform Poll

As there has been a recent surge in Patreon subscribers (thank you!) let me ask you about which FPGA model you are using. Select as many as you own. Note that multiple choice may only work through a web browser.

Bubble Bobble (MiSTer update), CPS15 (Pocket/beta), CPS2 (Pocket/public)

Work on the Splatter House core continues. The game graphics are correct and the demo is stable and does not hang up. But, the MCU seems not to be working correctly and as a result, the coin inputs get locked randomly. It looks like the days until Halloween are going to be scary to me as a developer!

One of the reasons behind the MCU not working was that the HD637...