JOTEGO

Poll: PGM or CPS3

Esperanza is done with Taito's Extermination schematics. Which system should she work on next?

She will extract the schematics for the chosen system from a donated PCB. This is a step required for a precise FPGA core.

Development, System 16 and A. Pocket Update

Esperanza returned from holidays this week and she has resumed the work on Taito’s Extermination hardware. This was pretty much done before her holidays but as usual, small details take a long time to get done. She has been cleaning up the schematics and will be running electrical rule checks next week. The core for these Taito boards is quite advanced too, with the CPU and sound chips connec...

Pocket: Ghosts’n Goblins

Sorry for the long wait, but this has been much harder than expected and you will see why soon! Today I proudly present a Pocketarcade core compatible with the Ghosts’n Goblins hardware. This core isthe same one working onthe other FPGA platforms. This means that JOTEGO supports now the same core running in seven platforms, without touching a comma in the core itself.

How to set up this...

Super Hang On beta

I stopped working on the Out Run core on the 18thof August after a frustrating debug week. The core was hanging up right at the start and I could not find the problem. I published the source code in the hope of another developer finding the problem. And open source worked its magic. Gyurco, who I have already mentioned in the past, is a developer from the MiST scene. He found the problem in a f...

NeoGeo Pocket CPU: Test Coverage

For the last two weeks, Samuel has kept working full time on the NGP CPU. I asked him to use a FOSS tool called covered to check the test bench converage. But, what is coverage? In the early days of digital electronics the engineer had to manually calculate all the digital functions and choose individual logic gates (AND, OR, etc) to implement them. The design ...

Karate Champ

The 80’s karate season starts today. Data East’s Karate Champ was an extremely popular game in the arcade and the home computer versions. I think we were all crazy about karate and ninjas back then. TV made it look normal to have a ninjagang in your neighbourhood. Karate Champ is a simple game in technical terms, even for 1984 it didn’t feature scroll and only had four colours per graphic...

Extermination / NeoGeo Pocket

Español abajo / 日本語は下記

Esperanza finished Taito’s Extermination schematics today before heading for her holidays after her first year working for JT. During this time she’s extracted schematics for Konami’s Kicker, Konami’s Ping Pong, Data East’s Sly Spy, Gun Bird 2, SEGA’s System 18, CAPCOM’s Bowling and Twin Cobra. She’s taken measurements f...

Roc'n Rope Beta

Although I had not planned to release a new game this week, I needed to work on something relaxing and chose to spend two days making an 8-bit Konami core: Roc’n Rope, designed by Tokuro Fujiwara. This is mix of a puzzle game and a platformer. You have to climb your way to the top where a phoenix waits for you. In order to climb, you use a rope. Fujiwara extended these mechanics a few years l...

Update on the Pocket

Esperanza spent her week finishing the Renegade PCB schematics. Although we think that we understand everything now, we want to let the schematics as correct and neat as possible for maintenance of original equipment and historical documentation. She still has a couple more days to finish them. The plan is to present the final version next Friday.

This week I took a detour and studied the...

Renegade Beta & Pang! Public Release

Update your jtbeta.zip key. Find it attached. The Pang! core has been promoted to public release.

Renegade is a game I had wanted to work on for a long while. I bought the PCB and had it sitting in a cabinet until this month. Esperanza started working on it and has already completed the sound and game CPUs. She’s still struggling with the graphics board and I think she’ll need to spen...

Out Run Jukebox

After three intense weeks, we haven’t been able to get Out Run to boot correctly. It boots to a halt but if you press F2, you can enter the service menu and play the tunes. So I suppose we have an Out Run jukebox core at this stage. The same goes for Turbo Out Run. With Super Hang On the situation is a bit bette...

Support for Analogue Pocket

I saw an announcement by Analogue today talking about Open FPGA... I wonder if this means that they're finally going to open the platform to community developers. 

I was wondering if you would be interested in getting my cores working on the Pocket too. Supporting a new platform on JTFRAME takes some work, so I don't want to do anything that you, my patrons, won't like.

Should ...

Out Run Progress & Renegade

Short update this week to tell you that work on the Out Run system continues. The game currently boots to a halt, although the service menu works. Too bad the built-in checks cannot find any problems with the core. I have moved my attention to Super Hang On, which is like Out Run but shares the sprites chip with System 16B. This one boots and goes through the demo loop, but the road is just a s...

Vigilante (public release) - SSF2T and other service releases

Español abajo - 日本語は下記

Many items to announce this week:

- Vigilante core promoted to public release. Source code here.

- Pang (beta core) supports bus contention when accessing video memory (better time accuracy)

- System 16: Dynamite Dux and Golden Axe slowdown fixed. Dynami...

Block Block / Dokaben / CAPCOM World

Español abajo - 日本語は下記

I was one to fall for the simplicity of Arkanoid in my 8-bit home computer. I thought with the first two Arkanoid games, the series was over and didn’t give credit to any other block game. Then I came across CAPCOM’s Block Block. This game brought fresh air to the genre five years after the first Arkanoid was released.

Althoug...

CAPCOM Bowling Schematics Ready

We have completed the schematics extraction of this track ball game. It is a very interesting piece of hardware because it comes from CAPCOM but uses only standard devices. Unlike the Pang! hardware, where you could see some CAPCOM custom chips shared with 1943 and other games, this bowling game seems to have been engineered by a completely different team.

The game uses two m6809 CPUs. Th...

Super Pang (support added to JTPANG core)

Super Pang

After the warm receiving Pang! got last week, I am very glad to bring Super Pang today. The game runs on the same board with small configuration changes so it wasn’t too hard to make it work. The core itself supports the hardware better but there are still a couple of things to iron out. There will one more beta about this hardware, probably next week, adding...

Pang!

This game, with no large demons, no hero plot and not even screen scroll, is one of the most enjoyable arcade titles ever. Show it to any kid and they’ll love it too. Pang! is also an interesting title because the hardware was developed by CAPCOM, and they also published games for this 8-bit platform. As I have done many CAPCOM systems, I was interested in this one from the technical point of...

NeoGeo Pocket Update

I have been working exclusively on the NeoGeo Pocket for the last two weeks. I have the instruction set implemented for the CPU now, with the exception of the three instructions related to interrupt and micro-DMA processing. The CPU logic takes at the moment over 3.7k lines of code. This is surprisingly less than the Z80 core that we use (4.3k lines) even though this CPU is like a 32-bit Z80 pl...

Vigilante (beta)

NB: The files are available in JTBIN via update_all or in the #betafiles Discord channel

Vigilante is a game that goes with no presentation. Everyone remembers the satisfying sound that kicking and punching produced in this title. But let me talk to you about some technical curiosities:

- The game still useda Z80 as the main CPU in 1988. As this CPU was starting to be a bit slow for...

The Speed Rumbler/Twin Cobra/Robocop…

The Speed Rumbler

- Extracted layer priority circuit from PCB and fixed the FPGA core with it
- The screen had an 8-line offset, which is corrected now
- The sprites position was slightly offset too
- There was a noisy line when the game was in flip mode
- The default sound balance had the FX too loud

After this, there are no known issues for this game.<...

Ghosts’n Goblins Color Flash

A couple of years ago, someone wrote me asking about yellow flashes in Ghosts’n Goblins game PCBs. I thought it was due to some timing problem in the aged hardware, which probably just got worse with temperature as the board got powered for longer time. However, this week I came across a video from an original PCB that showed this yellow flash effect. It was very prominent. I remembered then ...

Track & Field (beta)

This is the original button smasher: Track & Field. We have already seen a sequel to it: Hyper Sports, and we visit the original this week. This board was donated by Gyrrus about a year ago along other ones. He was worried it was taking too long to deliver the core, but it’s finally here. These things just take time. We also approached the hardwarestarting with Kicker, and working our way...

Rastan Saga

Important note: Road Fighter, Konami’s Ping Pong and Hyper Sports are promoted to public releases today. For the other games in beta phase, you will need a new beta key (jtbeta-zip). The new key is attached to this post, copy to MiSTerFPGA’s games/mame folder. Do not unzip it.

We come back to the 16-bit arcade world this week with a real classic: Rastan Saga. This game has an...

Konami's Ping Pong

Following on the Konami series of games before Contra, we have done an in-depth research on Konami’s Ping Pong (GX555). Super Crow provided us with an original PCB. We extracted the full schematics for it, measured the custom chips and wrote a custom firmware to execute on the board to test some assumptions. Please see the full report attached to this post. The report covers the diff...

Hyper Sports (1984)

As you may know, I’ve spent most of the week working on the NeoGeo Pocket core. I’ve been implementing the video subsystem before hooking it to the CPU. The CPU module is not complete yet but it’s good enough to try connecting it.

There was also time to add support for Hyper Sports to the Road Fighter core. Although strictly not the same board, the two games are very similar in term...

Road Fighter Files

Find the Road Fighter beta files attached. Remember that you can get them easily by using the update_all script. They are also available in the #betafiles channel in our Discord server.

Road Fighter

Konami knew what made a great arcade: a short introduction, clear rules and fast gameplay. Road Fighter is a clear example of that recipe and it worked well in home ports too. The NES and MSX version are dearly remembered by many users.

There’s an interesting technical quirk about this game. The game field is vertical, with a scroll going from top to bottom. However, Konami used the sam...

Sly Spy & Boulder Dash 2

Sly Spy

This secret agent was due to visit us last week, but apparently he had a sabotage mission to do first! It took me four days of debugging to find out why the game wasn’t booting up. In the end, it was a single line missing. Once added, the game run without any need for more edits. That’s the world of digital design: one or zero!

If you haven’t played Sl...

Research & Development

We spent the week purely on research & development activites. Esperanza got quite far with the Sly Spy schematics (see the attached file) and I implemented 15 more instructions in the NeoGeo Pocket CPU. The CPU has now about 80% of its instructions implemented. I think the CPU needs two more weeks, and then I can start working on the rest of the NeoGeo system.

For Sly Spy, we will see...