JOTEGO
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World Cup: Analog Controls and Audio Volume
🕑 Added 2024-11-29 12:17:12 +0000 UTCWork on Tehkan World Cup electrical schematic diagrams is finished. It has brought up a number of new discoveries on this hardware:
correct video timing (including frame rate)
3kHz antialias audio filter for PCM
16-step volume control for PCM audio
priority control for character and sprite layers
Comparing to last week's update, the new version of the core implements:
analog controls via analog stick on game pad
antialias audio filter and variable audio gain, matching PCB
video layer priority control, matching PCB
DIP switches are correctly read by the CPU
Analog controls totally change the game experience. Not because you would like to walk slowly towards the goal, but because you can now do smooth diagonals so you can move around opponents in a natural way. Trackball controls are not supported yet. I have not been able to achieve a nice experience with them yet.
Volume Control
One of the most interesting parts of this board is the analog volume control for the PCM sound effects. The ADPCM used for sound samples on this game is the OKI-M5205. This chip did the ADPCM decoding and the digital-to-analog conversion, but it did not have any sort of volume control. Tehkan's hardware engineer added this feature by connecting four external resistors via controllable switches. The sound CPU could decide which resistors would be used to connect from the OKI chip to the sound amplifier, effectively reducing the sound from as much as 20.8dB to as little as 6dB.
This feature is actually used in the game in order to control the drums and other sound effects. This was an unknown feature. The MAME documentation had identified that there was data written by the CPU, but they could not guess what it was doing. I will report this in detail to MAME's team for implementation. But, as of today, you are the first people to hear this effect again.
Grid Iron
There is another game currently playable on this core: Grid Iron. This is the American football game for which the hardware was originally done. The cabinet had a 7-segment display for each player, hidden from the view of the other player. This was used to select the team formation. We currently do not have a nice way of reproducing this feature. On top of that, I am not so convinced that this game will be played at all taking into account that it was a commercial flop. So for now, I am not implementing the formation displays. Indeed, I think modifying the software (via a ROM hack) to display the formation on screen would be better for the general modern player. Anyway, the game is available and playable on today's update.
Other Updates
JTWWFSS: fixed bad graphics on right side of the screen on Analogue Pocket
JTS18: fixed coin assignment on Moonwalker
Upcoming Work for End of 2024
I am finishing the work on The FairyLand Story beta core, which is the predecessor of Bubble Bobble. When we started working on the schematics, we were not expecting any findings. I still wanted to do them for preservation. But, extraction of the PCB schematics turned out to be full of surprises. The emulation of this game is surprisingly not accurate in many, many ways. More on this for the beta release.
There is one more beta core I want to get out. This time, a 90's game of my choice for a change! I am targeting the evening of the 5th of January 2025 for this. It is a big system and a hard schedule, but the motivation is high!
Comments
JOTEGO
That is an intermittent issue on the Pocket version that I am not able to replicate, so it comes and goes randomly. I am tracking it here: https://github.com/jotego/jtcores/issues/515
Icehawk
On Analogue Pocket I noticed Outrun and Turbo Outrun are both malfunctioning again with latest update like previously where most of the assets are not showing up on screen.
TheGeez
I wonder if there is hope for the Taito Z System or did Outrun scar Jotego for life? Could it be that scaler arcades are generally a challange on the MiSTer due to memory bandwith limitations?
JOTEGO
PGM is in the backlog. I have an unit and some cartridges. But there are no immediate plans for it. There are no plans either to expand to more social networks.
JOTEGO
There are no plans to expand to more social networks.
Adrien Duchemole
Good to know Thanks for your reply
JOTEGO
It might be possible by circumventing the standard MiSTer framework, which duplicates the screen.
Dan Doyle
It works fine on mistercade, you just need to slightly tweak your horizontal hold on your monitor
Amador
Hi Jotego, sorry for the 'out of topic' question : given the circumstances about Twitter/X, do you think you will open another account on Bluesky (or better : Mastodon) ?
Alex Limi
Audio filter work much appreciated! Getting that stuff right is very important. Will we see you on Bluesky soon? Looks like a significant portion of the retro scene successfully moved. PS: PGM is an amazing platform with a bunch of great games (as you know), and with a lot lower complexity than e.g. CPS3 (as you know), and certainly a lot more games for the effort needed (as you know). But I canโt not flag it ๐คฃ
Gillaxian
Please please please let the 90โs one be CPS3. ๐ค
rester159
Hey any update on System18 working properly on mistercade?
Edson Souza
Could the 90s title be a functional Mortal Kombat core? It would be amazing! Hehe. Jokes apart, thanks for the efort!
Arkade_UK
Top work ๐
JOTEGO
That's about the ROM file. I cannot help you with that.
Ryan Kasper
Thank you ๐
Stephen Lerch
I've run update all w/ premium option. I go into Alternatives and it informs me that the zip file does not exist for the latest betas. I must be doing something wrong.
JOTEGO
Note that some games appear in the alternatives folder, rather than the main arcade folder. This is particularly true for several 2p/4P variation of games.
Stephen Lerch
Stupid question. Is there an easy way to get the latest Beta cores on my MiSTer? I run Update All w/ Premium Core option but it doesn't seem to grab things like the X-Men 4 player Core and similar. I assume it has to do with Archive.org issues but I don't follow things well enough to know this for sure. Any help/info is appreciated.
Adam Davis
Ooh man ooooohhhh what is it!? ๐คค๐ค๐ผ
Andrea Bogazzi
Ok if is from the 90s is not rolling thunder. Your choice what could it be?
Christian Johansson
Thanks for all your hard work! Can't wait to see what "90's game" you're working on!
Pixel Cherry Ninja
Thanks JT and team. I look forward to what the 90s game is ๐ค
Adrien Duchemole
Good luck for the mysterious 90s title and thanks for the update and interesting explanation Clever trick to control the dac output volume As you mention the formation display problem on Grid Iron, I've wondered if it could be possible on a mister to handle 2 video outputs ? I ask that, thinking about nintendo's dual screen trilogy "Punch-out, Super Punch-out and Arm wrestling" As example, could it be possible to display the main game screen on a crt and the score/energy bars on a lcd screen using the hdmi output ? Thanks, and good luck !!
