JOTEGO

GunSmoke Core Beta MiST(er)

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I know Commando is good, but pardon me, GunSmoke is better! I really love the music of this game and the scenery. Technically, it is a bit more advanced than Commando. Its graphics hardware is right between Commando and 1943. It uses a hardware controlled background map so the CPU can...

Poll: one or two cores for 1942/Vulgus

I am pretty much done with GunSmoke and I have moved to Vulgus. This game runs on almost the same board as 1942. 

I could make the two games run on a single core. Or I could keep using the one-core-per-game approach.

What do you prefer?

Why not a single core for all CAPCOM pre-CPS games?

As I said in twitter, all pre-CPS CAPCOM are so similar we could call them CPS0. However, this is more a statement about design principles followed by the engineers than about the actual hardware.

Most of these games ha...

Commando Public Release MiST(er)

UPDATE: attached zip files now fix the key remap issue in MiSTer. There were also some graphic glitches and gameplay errors that seemed to be caused by a low speed CPU. I have increased it from 3MHz to 6MHz, which goes against the Commando schematics. I'll measure the real bo...

Commando Pause Screen

I am adding the pause sceen to Commando before the public release. Please check out the video and let me know if there is something wrong with your name, or if you think you should be in the list but you are not.

Notice that patrons that appear here are those who were in $10+ tiers at the time of the Commando beta post ...

Exploring C64 SID Schematics

The Commodore 64 SID chip is something it should already be done perfectly.  There are schematics for the two SID chips. What else would you need?

Well, after looking at the schematics I can see some reasons why people hear differences between SID implementations, real chips and ev...

Popeye Sprite Overlapping

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You probably have noticed that on Popeye when two sprites get close to each other, there are black boxes hiding the second sprite. This looks like a glitch, but it is a design limitation of the original hardware. Check out this video recorded directly from a real Popeye...

August Work Plan

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-Work on Commodore 64 SID chip
-Update CAPCOM cores   
 1. Sound issue on G&G second level
 2. Sprite alignment
 3. 1942 flip screen option for MiSTer
 4. Prepare avatars and pause screen of Commando (needed for publ...

Popeye Release Party!

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Popeye core is finally ready and we are celebrating it with SmokeMonster! Tomorrow night (10 PM eastern USA time) he will show the core on his YouTube channel. He will also play Commando and...

Popeye Core Update

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I spent several hours this weekend on advancing the Popeye core. It went from no sprites at all, to pretty much working. I discovered that the ROM set we all use in MAME has the address bits inverted for the object ROMs. At least, when compared with schematics.

Sprite hardware in Popeye is rea...

Boards from Andrew Received

Fresh news. Remember how Andrew had offered a loan of his Double Dragon PCB? The board finally arrived today in outstanding shape. Very nicely packaged and luckily, no custom tax this time.

Andrew also sent a Moonwalker original board (System 18). I have now enough material to tackle a System 16 core as Pierre G. had l...

Commando Core (BETA) Release

I am happy to announce you that all +$3 patrons will receive a download link to the Commando core for both MiST and MiSTer in the next few minutes.

I am also proud to introduce Bruno the ROM Master to you. The ROM Master has produced the accompanying ba...

Arcade PCBs from Japan

The outcome from the poll about which board to buy was to get Double Dragon. However, Andrew Moore,  one of my earliest patrons, offered to loan me his Double Dragon PCB. We are still looking at the best way t...

New Core: Commando

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As I am travelling and I cannot use the FPGA right now I went back to looking at schematics. I started reading the Commando schematics and found that the video hardware is almost identical to that of Ghosts'n Goblins. Game CPU and sound CPU peripherals are also similar to the other CAP...

To buy or not to buy

I am travelling this week and next week in Japan. I have located a Street Fighter 1 board in a shop. This is a rare game and there are no schematics available. I also found Renegade and   2019-07-05 13:00:32 +0000 UTC View Post

Popeye Sprite Hardware

(español abajo)

Popeye has an unusual sprite generator. The CPU writes the sprite information (which tile, which colour palette and where in screen) in RAM. Once per frame a DMA circuit triggers and copies that region of RAM into a separate buffer. However, there is not enough time to read the buffer c...

1942 Logo: Emulation vs Arcade/FPGA

Not many people noticed, certainly Sorgelig did, but the CAPCOM logo at the boot up screen of 1942 is different in MiSTer and MAME. MAME version shows two different boxes moving, whereas MiST(er) version shows just one long box whose length varies. I made that core using only schematics. I didn't have a real PCB and I couldn'...

Popeye Update

I am sorry I am running late with the beta release but I'm happy to announce that I made a critical step forward this week:

Popeye has a lot of encryption and obfuscation on the board. It is impossible to get it right just with the schematics. However, Scralings had found a report on the obfuscated logic 2019-06-24 21:59:55 +0000 UTC View Post

Improved Simulation Flow

I actually had scheduled yesterday as the release date for the beta Popeye core but I got stuck with a problem in the DMA circuit. I thought it would be nice to be able to simulate the schematics directly without having to convert the...

Research Work

I was asked to publish a bit about how I develop the cores. Today I will talk about a small topic: the horizontal pixel count of Popeye.

All video systems need to count pixels. There is always a horizontal count, H, and a vertical count, V. Popeye PCB schematics are ava...

Popeye Graphics Explained (2)

Following on this post, let me explain further how the graphics hardware rendering the background worked.  

The general idea is that a memory is written by the CPU with some pixel information and some hardware counters are used ...

2019-06-07 08:00:02 +0000 UTC View Post

Items bought thanks to you!

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Since I started with Patreon I have received a lot of support from you, my patrons. This has been a great incentive to work harder and also with greater enjoyment. But with the extra money I have been able to improve my development setup. These are some of the things I have bought recently: a new 2019-06-04 20:27:42 +0000 UTC View Post

Popeye Core

For the last week I couldn’t an image at all first, and then I could only get a display full of zeros. I have finally got real images from the core.

There seem to be a number of issues. But once you get an image it is easier to diagnose what is going on. There is still some problem with the reading from SDRAM and mayb...

Popeye Graphics Explained (1)

(español abajo)

Popeye is a great example of single-screen games. Nowadays we are used to exploring giant worlds but Popeye reminds us that a good game design needs no more than one screen. But how was that screen rendered?

The engineers behind this awesome hit combined three different graphics systems. Let's see...

Popeye Release Schedule

 I have resumed my work on the Popeye arcade core.  This is the schedule I have for it:

* 30th May: paid post to identify supporters of this core, including patrons of the pause screen

* First week of june: beta release (MiSTer as a priority platform)

* July: public release

T...

1943 Public Release: MiSTer

Sorry for the long wait. The public version of 1943 for MiSTer is finally here. Thanks a lot to all patrons. This is the first version for Avatars in the pause screen. I think they are really cute!

Remember that you have to press both fire buttons to perform a loop.

Please find the file attached. I think you shoul...

Update on the Status of 1943 for MiSTer

About 10 days ago I released 1943 for MiST, but I know most of you want the MiSTer version. However, the port didn't go as expected, why?

MiST FPGA can work well with different circuits operating inside it at different clock speeds. The MiST SDRAM chip is also relatively close to the FPGA and that makes it more reliable...

1943 Public Release (Part 1)

Sorry for the delay. The preparation of the release files has been harder than expected. I develop everything on MiST and I run trials without sound for faster compilation. When I added sound to make the release files I ran into memory problems because of the pause screen avatars. I spent two days trying to work around it but...

1943 Pause Screen

Last weekend I completed the 1943 core pause screen with patrons on $10+ tiers. For the first time, the pause screen includes avatars of $20+ patrons. It has been very interesting to convert the images to the arcade format. Remember that the pause screen is rendered using the arcade GPU. I ba...

Real Audio Tape on 8-bit CPU cores

I have written a module which once added to the 8-bit CPU cores (Spectrum, Amstrad, Commodore, Atari...) will enable direct tape connection to the MiSTer board. I mean, an actual tape or other audio source. Now other people are looking into finishing this, with proper support in the MiSTer framework and I/O b...