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FPGA Based Videogame System

Interest in an FPGA Videogame System  

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  3. 3. Games Should Run From...

    • SD Card / USB Memory Sticks
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The impression I got from the classic gaming discord is that maybe 10% of the members play video games for more than 5 minutes a month, and the other 90% just buy gadgets, test obscure games and accessories, and speculate what future gadgets will do.

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2 hours ago, zetastrike said:

The impression I got from the classic gaming discord is that maybe 10% of the members play video games for more than 5 minutes a month, and the other 90% just buy gadgets, test obscure games and accessories, and speculate what future gadgets will do.

That kinda sounds like here too! 😄

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Mega Sg CRAM dots are being weird on Sonic 3 & Knuckles. Yes, I like CRAM dots.

 

They display properly in Hydrocity and other places where the CRAM dots are at the waterline and hidden in the water's little animation thingy, but they are weird in places where the water doesn't have that animation. This does not happen on my Nomad, where the CRAM dots behave correctly (correctly being that they should not show up when the water isn't animated), and I think it doesn't happen on the Mega Drive, either. Does this happen to anyone else? Yes, before someone asks, the 0o lives counter is what happens when you get 100 lives, so no, that's not a glitch and is working as it's supposed to.

Pic_0421_287.thumb.jpg.3c8cb580724a4f5642cadfc448852beb.jpg

Pic_0421_288.thumb.jpg.627911a7c9d55288f9dd15782c71545e.jpg

Edited by Steven Pendleton

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Have you guys in Discord heard any rumors of the new MegaSG firmware? I am eagerly waiting the scaler fixes, non-selective pixel blending in particular.

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19 hours ago, Steven Pendleton said:

Mega Sg CRAM dots are being weird on Sonic 3 & Knuckles. Yes, I like CRAM dots.

 

They display properly in Hydrocity and other places where the CRAM dots are at the waterline and hidden in the water's little animation thingy, but they are weird in places where the water doesn't have that animation. This does not happen on my Nomad, where the CRAM dots behave correctly (correctly being that they should not show up when the water isn't animated), and I think it doesn't happen on the Mega Drive, either. Does this happen to anyone else? Yes, before someone asks, the 0o lives counter is what happens when you get 100 lives, so no, that's not a glitch and is working as it's supposed to.

Pic_0421_287.thumb.jpg.3c8cb580724a4f5642cadfc448852beb.jpg

Pic_0421_288.thumb.jpg.627911a7c9d55288f9dd15782c71545e.jpg

Not sure exactly what I am looking for or what cram dots are. I have my MegaSG hooked up to a CRT via the Analogue DAC. In the menu, go to Settings > DAC > Extra Features >  *There is a check box to Enable/Disable Cram Dots.* This may help. Seems a bit innocuous to me. Most people would never notice unless it was specifically pointed out. I am not sure how to get to this feature when the MegaSG is hooked up to a flat panel via hdmi. The settings/options are different when it is hooked up via hdmi as opposed to the DAC. I would guess it is in there somewhere as an option when hooked up via hdmi.

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9 hours ago, vanfanel said:

Have you guys in Discord heard any rumors of the new MegaSG firmware? I am eagerly waiting the scaler fixes, non-selective pixel blending in particular.

Haven't heard a peep about a new MegaSG firmware. Best guess is Kevtris is buried in development for the Pocket. He has been radio silent for a while now.

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13 hours ago, RetrogamerX said:

Be quick the Nt mini Noir is back up for preorder

Thanks for the heads up just ordered. I know they will come out with a plastic one but I like the DAC built in as I will be using on CRT TVs only.

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Bit of a long shot but I wonder if anyone can help?

 

I'm trying to get the following set up working:

 

Mega SG

32X

Mega SD

Analogue DAC

Retro Access (US) Analogue DAC to SCART cable

Retro Gaming Cables (UK) Mega Drive 2 RGB SCART Packapunch PRO cable

B&O MX7000 CRT

 

I finally got the final cable to put it all together and I get a rolling green mess on my TV.

 

The 32X is an auto region switching one. This is the first time I've tried to use it since buying it. My TV works great with other consoles on CSYNC such as my Japanese Saturn. My SG and SD obviously works well on an hdmi screen.

 

SG has the latest jailbreak firmware. I've tried the PAL and NTSC switch on the DAC.

 

I've tried the 3 sync settings in the SG settings - those are all i can find when my SG hdmi is going into an hdmi screen. Is there a way of seeing the extra settings somehow if i can't get a picture on my CRT.

 

I've searched the Analogue site and can't seem to find a DAC firmware which would imply the one it shipped with is the latest one?

 

As it's a very specific set up, i have no way of swapping the middle bits out at all to test (I don't have a real Mega Drive). I was hoping there was a small chance that somebody has a similar setup or that they can say "you fool, your SCART has a 5v doodah and this will never work".

 

Many thanks

 

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1 hour ago, Turnbl said:

Retro Access (US) Analogue DAC to SCART cable

Sorry I meant to say:

Retro Access (US) Analogue DAC to 32X cable

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On 4/22/2020 at 12:15 PM, Sneakyturtleegg said:

Not sure exactly what I am looking for or what cram dots are. I have my MegaSG hooked up to a CRT via the Analogue DAC. In the menu, go to Settings > DAC > Extra Features >  *There is a check box to Enable/Disable Cram Dots.* This may help. Seems a bit innocuous to me. Most people would never notice unless it was specifically pointed out. I am not sure how to get to this feature when the MegaSG is hooked up to a flat panel via hdmi. The settings/options are different when it is hooked up via hdmi as opposed to the DAC. I would guess it is in there somewhere as an option when hooked up via hdmi.

CRAM dots are color RAM dots. All real hardware has them, but they do not appear in most emulators, official or not, to my knowledge, so it's not surprising that you don't know what they are. The only emulator that I am aware of that has the option to enable/disable them is the Mega Sg. I imagine some of the better software emulators (BlastEm) and maybe the MiSTer might have options to enable them, but I don't use any of those, so I can't say.

 

If you look at the pictures I posted, you can see the CRAM dots there where they are not supposed to be since the water is not animated. Use a real Genesis or Mega Drive and you will not see CRAM dots there, but you will see them in some games' overscan areas and also where the color palette shifts at the water line in Castlevania, Sonic games where the water is animated, Gleylancer, and a few other games that use this method to change colors. On the Mega Sg, most of this works as on real hardware except the weirdly placed CRAM dots in Sonic 3. Sonic & Knuckles has no water, so don't go looking for it in Sonic & Knuckles levels. Maybe there are other games that I do not know of that have this error as well.

 

And here is the actual real explanation of how this works and also how blast processing, which is actually real, works, as it's somewhat related:

 

https://www.resetera.com/threads/how-did-sonic-achieve-transparencies-in-stage-4-labyrinth-zone.61243/#post-11348150

Edited by Steven Pendleton

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CRAM dots are color RAM dots. All real hardware has them, but they do not appear in most emulators, official or not, to my knowledge, so it's not surprising that you don't know what they are. The only emulator that I am aware of that has the option to enable/disable them is the Mega Sg. I imagine some of the better software emulators (BlastEm) and maybe the MiSTer might have options to enable them, but I don't use any of those, so I can't say.
 
If you look at the pictures I posted, you can see the CRAM dots there where they are not supposed to be since the water is not animated. Use a real Genesis or Mega Drive and you will not see CRAM dots there, but you will see them in some games' overscan areas and also where the color palette shifts at the water line in Castlevania, Sonic games where the water is animated, Gleylancer, and a few other games that use this method to change colors. On the Mega Sg, most of this works as on real hardware except the weirdly placed CRAM dots in Sonic 3. Sonic & Knuckles has no water, so don't go looking for it in Sonic & Knuckles levels. Maybe there are other games that I do not know of that have this error as well.
 
And here is the actual real explanation of how this works and also how blast processing, which is actually real, works, as it's somewhat related:
 
https://www.resetera.com/threads/how-did-sonic-achieve-transparencies-in-stage-4-labyrinth-zone.61243/#post-11348150
Despite all the people calling FPGA "hardware emulation" and traditional emulators "software emulation" to distinguosh it from original hardware, it really isn't an "emulator" at all. It's a hardware clone chip that executes the software with bits, busses, and clocks... just like the original. Literally the only thing that distinguishes it from a hardware clone made with ASICs is that the connections are reconfigurable so that it can also be changed to clone/replicate other hardware configurations too.

Yes, there is room for error but the same applies to original hardware clones like the 1chip SNES. Even the original hardware was designed with an HDL and transcribed to a chip which is what FPGA does dynamically. The difference is that dedicated chips can't be reconfigured since the connections inside are permanent and made using a lithography shadow mask.

It's a little like saying that EEPROMs are emulators because the data/configuration wasn't made permanent using lithography. That's silly because it's still a chip with the same internal arrangement of connections as a permanent ROM version. A huge number of original hardware chips inside games and arcade machines are made using ASICS full of premade logic units and all they did was define connections between them to get the function the engineers wanted... then replicated it when manufacturing the chips. An FPGA also defines connections between existing logic units only it doesn't need to be defined/replicated during manufacturing since it is "field programmable." That's the difference, which doesn't come close to the distinguishment between emulation and hardware.

My definition of an emulator is "software that interprets other software on non-native hardware." It has to look at the code, figure out what it wants to do, and translate that into something equivalent on the non-native host operating system/platform. An FPGA, OTOH, needs to have the hardware reverse engineered and replicated accurately enough to blindly execute the software in real time... actually, replicates the original hardware so closely that it can let the software execute itself. FPGA clones are hardware clones. Even better: They are hardware clones that can be fixed if there was an error cloning the hardware, unlike the glitchy 1chip SNES.

That isn't to say that someone can't use an FPGA to dump a ROM and then run the software on an emulator running on an embedded ARM SoC, but that was never an FPGA clone. If I used my Bung Doctor V64jr512 in that Hyperkin N64 emulator console, the Altera FPGA inside the V64 is a hardware clone of the cartridge addressing logic and memory space and the Hyperkin clone is still just a software emulator dumping the game and running it in a non-native host environment (ARM SoC with emulator software). Heck, there might even be a second FPGA involved to dump the N64 games and read/write save files.

The FPGAs are still performing their functions as hardware even if Hyperkin ultimately just throws the ROM dump to a ported N64 software emulator. The FPGAs inside Analogue consoles obviously replicate a lot more than the cartridge... they also replicate enough of the system to run the cartridge. That's the difference from software emulation and why "hardware emulation" is a misnomer (by that standard, the 1chip SNES is a "emulator").
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1 minute ago, CZroe said:

Despite all the people calling FPGA "hardware emulation" and traditional emulators "software emulation" to distinguosh it from original hardware, it really isn't an "emulator" at all. It's a hardware clone chip that executes the software with bits, busses, and clocks... just like the original. Literally the only thing that distinguishes it from a hardware clone made with ASICs is that the connections are reconfigurable so that it can also be changed to clone/replicate other hardware configurations too.

Yes, there is room for error but the same applies to original hardware clones like the 1chip SNES. Even the original hardware was designed with an HDL and transcribed to a chip which is what FPGA does dynamically. The difference is that dedicated chips can't be reconfigured since the connections inside are permanent and made using a lithography shadow mask.

It's a little like saying that EEPROMs are emulators because the data/configuration wasn't made permanent using lithography. That's silly because it's still a chip with the same internal arrangement of connections as a permanent ROM version. A huge number of original hardware chips inside games and arcade machines are made using ASICS full of premade logic units and all they did was define connections between them to get the function the engineers wanted... then replicated it when manufacturing the chips. An FPGA also defines connections between existing logic units only it doesn't need to be defined/replicated during manufacturing since it is "field programmable." That's the difference, which doesn't come close to the distinguishment between emulation and hardware.

My definition of an emulator is "software that interprets other software on non-native hardware." It has to look at the code, figure out what it wants to do, and translate that into something equivalent on the non-native host operating system/platform. An FPGA, OTOH, needs to have the hardware reverse engineered and replicated accurately enough to blindly execute the software in real time... actually, replicates the original hardware so closely that it can let the software execute itself. FPGA clones are hardware clones. Even better: They are hardware clones that can be fixed if there was an error cloning the hardware, unlike the glitchy 1chip SNES.

That isn't to say that someone can't use an FPGA to dump a ROM and then run the software on an emulator running on an embedded ARM SoC, but that was never an FPGA clone. If I used my Bung Doctor V64jr512 in that Hyperkin N64 emulator console, the Altera FPGA inside the V64 is a hardware clone of the cartridge addressing logic and memory space and the Hyperkin clone is still just a software emulator dumping the game and running it in a non-native host environment (ARM SoC with emulator software). Heck, there might even be a second FPGA involved to dump the N64 games and read/write save files.

The FPGAs are still performing their functions as hardware even if Hyperkin ultimately just throws the ROM dump to a ported N64 software emulator. The FPGAs inside Analogue consoles obviously replicate a lot more than the cartridge... they also replicate enough of the system to run the cartridge. That's the difference from software emulation and why "hardware emulation" is a misnomer (by that standard, the 1chip SNES is a "emulator").

Yes, I know. I look at it from the simple perspective of the fact that it isn't using real actual chips from an original console. To emulate is to imitate something else, and since it's not a real Genesis/MD, you could technically call it an "emulator" of sorts.

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Yes, I know. I look at it from the simple perspective of the fact that it isn't using real actual chips from an original console. To emulate is to imitate something else, and since it's not a real Genesis/MD, you could technically call it an "emulator" of sorts.

Sure, but we already call those "hardware clones" and people assume FPGA is something less when we call it "emulation."
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To me "hardware clones" implies at least an attempt to 1:1 replicate. I think there's room for ambiguity there, since that isn't fully the case as modern conveniences are usually grafted on to the FPGA recreation. The problem with using any of the existing definitions, without using an FPGA qualifier, is that they imply things that aren't true. This is the case whether you call them emulators or clones.

 

A question to anyone with practical experience with FPGAs... I do know that logic families differ in characteristic quite a bit. Can the FPGA emulate different logic family characteristics, is that accounted for in the translation with extra gates, or is it generally just ignored?

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1 hour ago, CZroe said:


 


Sure, but we already call those "hardware clones" and people assume FPGA is something less when we call it "emulation."

But don't forget that optical drive emulators are still called optical drive emulators!

 

Still, there is nothing inherently wrong with emulation. It's just that people associate it with piracy or other things of that nature and therefore it has a bad name. Little do they know that lots of old games that get rereleased on new systems are running under emulation since it's easier to program an emulator to run on your system than to partially rebuild a game to run on a modern system. I think I mentioned this before somewhere here. The PS3 is also apparently not capable of running PS1 games natively, so it does it using emulation.

 

And this has gotten completely sidetracked! CRAM dots! Are they weird like this for anyone else in Sonic 3?

Edited by Steven Pendleton
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To me "hardware clones" implies at least an attempt to 1:1 replicate. I think there's room for ambiguity there, since that isn't fully the case as modern conveniences are usually grafted on to the FPGA recreation. The problem with using any of the existing definitions, without using an FPGA qualifier, is that they imply things that aren't true. This is the case whether you call them emulators or clones.

Yes, there are multiple approaches you could take when cloning whether you are using an FPGA or not. One is to try to replicate the result 1:1 with what you'd get from an original chip without actually analyzing the way the original chip did it. The other is analyzing the actual internal structure/configuration of the original chip and copying that as close to 1:1 as possible. Both are prone to errors if they aren't checked and double-checked and tested extensively.

 

As for whether it has to be a 1:1 attempt to be considered a hardware clone, well, an NES On A Chip (NOAC) condenses many chips onto one (no discrete CPU, PPU, and memory) without attempting to replicate discrete chips and yet it's still considered a hardware clone. The 2chip and 1chip SNES/SFC revisions also take shortcuts to combine the functions of multiple chips. Traditionally that's half the point of hardware cloning: do it cheaper to displace the original.

 

Consumer FPGA devices abandon the cost concern for the flexibility and expandability afforded by dynamic reconfiguration on-the-fly ("field-programable"). Before consumer applications took advantage of their field programmability they were mostly used for engineering or expensive low-volume logic devices where spinning dedicated silicon was less cost effective due to poor Economies of Scale. Engineers use them to prototype HDL before manufacturing a higher-volume of non-FPGA chips when the Economies of Scale support spinning silicon. You know: testing the HDL on FPGA before getting an expensive lithography mask made for dedicated chip production where any errors would get permanently replicated across every chip manufactured.

 

I guess I'm just trying to say that anything that might make an FPGA less than a 1:1 hardware clone can also apply to traditional dedicated/fixed chip clones and yet no one tries to call them emulators even when they are less than perfect (Reverse duty cycle audio in a NOAC? Glitches in a 1chip SNES?). That's why I feel it's unfair to distinguish it from hardware clones and imply a closer relationship to software emulation.

 

But don't forget that optical drive emulators are still called optical drive emulators!

 

Still, there is nothing inherently wrong with emulation. It's just that people associate it with piracy or other things of that nature and therefore it has a bad name. Little do they know that lots of old games that get rereleased on new systems are running under emulation since it's easier to program an emulator to run on your system than to partially rebuild a game to run on a modern system. I think I mentioned this before somewhere here. The PS3 is also apparently not capable of running PS1 games natively, so it does it using emulation.

 

And this has gotten completely sidetracked! CRAM dots! Are they weird like this for anyone else in Sonic 3?

You're right, and even my Bung Doctor V64jr512 calls itself a "cartridge emulator," but an ODE is often an "emulator" in more ways than just the dictionary definition that obviously predates our use of it for these things. For example, very few would attempt to replicate the physical characteristics of the disc beyond introducing delays and such to simulate seek time and spin-up and such things. They might find some behavioral quirks of the original drive and attempt to simulate those if software is impacted, but that's about as far as they go.

 

ODEs typically ignore unnecessary physical characteristics and emulate the drive at the protocol level or whatever bus they connect to. Most really are emulators in the same sense of the word where they interpret instructions and translate them to something that approximates the function on non-native hardware. "You want sector whatever of the disc? Lemme grab those bytes from the ISO file and pretend to have read them from the disc."

 

Emulation is great. A hardware clone optical drive would have to have a spindle motor/hub, laser, limit switches, ...the works! While an ODE is emulation, the software itself is still executing natively on original hardware. It's the best of both worlds, really. atariage_icon_smile.gif

 

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4 minutes ago, CZroe said:

You're right, and even my Bung Doctor V64jr512 calls itself a "cartridge emulator," but an ODE is often an "emulator" in more ways than just the dictionary definition that obviously predates our use of it for these things. For example, very few would attempt to replicate the physical characteristics of the disc beyond introducing delays and such to simulate seek time and spin-up. They might find some behavioral quirks of the original drive and attempt to simulate them if software is impacted, but that's about as far as they go. They typically emulate the drive at the protocol level or whatever bus they connect to. Most really are emulators in the same sense of the word where they interpret instructions and translate them to something that approximates the function on non-native hardware. "You want sector whatever of the disc? Lemme grab those bytes from the ISO file and pretend to have read them from the disc."

Emulation is great. A hardware clone optical drive would have to have a spindle motor/hub, laser, limit switches, ...the works! While an ODE is emulation, the software itself is still executing natively on original hardware. It's the best of both worlds, really.

Yeah, ODEs are really awesome. I love the SSDS3 and the MegaSD. I can't choose which one I love more. I imagine you love your UperGrafx, as well! With HuDebug now potentially coming back to life, the PC Engine GT is going to be AMAZING. Not sure if that counts as an ODE, but I guess it sort of does.

Edited by Steven Pendleton

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Yeah, ODEs are really awesome. I love the SSDS3 and the MegaSD. I can't choose which one I love more. I imagine you love your UperGrafx, as well! With HuDebug now potentially coming back to life, the PC Engine GT is going to be AMAZING. Not sure if that counts as an ODE, but I guess it sort of does.

Yeah. As far as I can tell, HuDebug is replicating the System Card and dock hardware with an integrated CD-ROM² ODE. I'm told that all the EXT port pins needed to connect CD hardware to the HuCard slot are there except for one, so it seems HuDebug got around that one somehow.

 

Like the Neo Geo AES cartridge slot, the HuCard slot only has a mono audio input. I hope HuDebug supports optional external mixing with a headphone jack loop-back cable but I doubt it will. That means we will probably be stuck with mono CD audio, much like an AV modded TurboGrafx-16 would be when connected to an RAU-30 ROM² Adapter: RAU does not carry video so you would have to get video from the TG16 and audio from the IFU-30 Interface Unit if you want stereo.

 

No idea why Neo SD Pro didn't do the loop-back cable for Neo Geo CD games since it makes even more sense there.

 

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8 minutes ago, CZroe said:

I guess I'm just trying to say that anything that might make an FPGA less than a 1:1 hardware clone can also apply to traditional dedicated/fixed chip clones and yet no one tries to call them emulators even when they are less than perfect (Reverse duty cycle audio in a NOAC? Glitches in a 1chip SNES?). That's why I feel it's unfair to distinguish it from hardware clones and imply a closer relationship to software emulation.

This is going to probably be unsatisfactory, because we're both against using terms that smuggle-in meaning they shouldn't, we're just coming at it from different directions. I also wouldn't call a glitchy hardware emulation a clone, but I'm aware that's the popular definition. Not much to be done about it, because the masses make the rules for english; "awful" used to mean something filled you with "awe".

 

When I hear "hardware emulation" I don't think in quite the same negative terms you're hearing. The qualifier makes a big difference to me, but I accept it may not to others.

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3 hours ago, CZroe said:

Sure, but we already call those "hardware clones" and people assume FPGA is something less when we call it "emulation."

I feel like calling it a hardware clone has more of a negative connotation than emulation. I can't think of a single hardware clone that isn't a POS, but there are several very good emulators. Maybe all those Retron units shouldn't really be called hardware clones (clone being like for like, which and FPGA is much closer to), but the names already stuck, so is as it is. 

Edited by jamon1567
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Just now, jamon1567 said:

 I can't think of a single hardware clone that isn't a POS, 

At this point in time aside from Mister and the Analogue products, what other hardware clones are there?

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2 minutes ago, NE146 said:

At this point in time aside from Mister and the Analogue products, what other hardware clones are there?

I was referring to something the the Retron units which I often hear called hardware clones. That is what I meant. But since you mention the Analogue products, it was in vogue for a while to refer to them as hardware simulation. Whether that is definitionally accurate, I don't know.

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Ah yeah, I would consider those emulation boxes I guess. And yes they are POS :lol:

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