Atari Lynx Core

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Atari Lynx Core

Unread post by Xbytez »

Atari Lynx core has now been released

https://github.com/MiSTer-devel/AtariLynx_MiSTer

See more in the video:



Robert Peip (FPGAzumSpass) also now has a Patreon page in case you want to support his work:

https://www.patreon.com/FPGAzumSpass
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Re: Atari Lynx Core

Unread post by Alkadian »

Excellent news, thanks for sharing!
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by hiddenbyleaves »

Incredible work! Well done.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by Bennehana »

Awesome!!!

Nerver played Atari Lynx
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by SuperBabyHix »

This is great news, thanks so much FPGAzumSpass. Had one for a long time and loved California Games.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by kubbie »

Always glad to see a new core. Thanks very much.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by morgoth »

Thank you FPGAzumSpass, all of your hard work is very much appreciated!
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

Very exciting to see this core developed this far already. I can imagine the lack of technical documentation and the variable frame rate makes development a bit tricky. Maybe RJ Mical (one of the original hardware designers) would be willing to help out. I met him once and showed him my Lynx Amiga Boing demos (he's the original author of the Amiga Boing demo as well), he's a really fun and passionate guy. I do still have his e-mail address but I didn't get a response after sending him the demos on his request, he's a really busy guy as well.

I've been a big fan of the Lynx since buying one about thirty years ago, I have collected almost all commercially released games for it. I've upgraded one of my Lynxes with a McWill display and VGA output, sadly that doesn't support variable frame rate.

I've commented on FPGAzumSpass' YouTube video and 24Mhz overclocking will probably be implemented in this core as well. You can do that as a hardware mod on a real Lynx, it makes slow games more playable (but does increase audio frequency and music speed as well, maybe games could be patched for it). I'm hoping for home brew that supports 24 Mhz (the original clock frequency of the Lynx, but lowered to 16 Mhz to increase battery life).
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FoxbatStargazer »

Didn't see it mentioned here but it looks like beta core is available to paterons.

Owlnonymous showed off a bunch of games on the beta from about 7 minutes in. No sound yet but it looks like most of the library is playing very well, including marquee titles like blue lightning, electrocop, slime world, etc. With this much work done its very believable that we can have a fully working core quite soon.

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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

I was there, it was a really fun stream. The Lynx core is already very good. Apart from the audio missing, of course, not all games had working collision detection. I know the Lynx has a special kind of collision detection using a hidden frame with sprites, this is not often used in games luckily.

The only other thing I saw was a very slight seam in the ground scenery of Blue Lightning. That might even be there on a real Lynx, but I never noticed it.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by Waifu4Life »

Not really my cup of tea, but hey, that's one more core closer to make it the ultimate all in 1 system.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FPGAzumSpass »

LamerDeluxe wrote: Mon Mar 01, 2021 10:12 pm The only other thing I saw was a very slight seam in the ground scenery of Blue Lightning. That might even be there on a real Lynx, but I never noticed it.
The way the Lynx works it could happen if the developers don't do the double buffering right, but more likely it's the core currently.

The beta core is not synchronized to video output currently, just outputting 60Hz.
So you have tearing from time to time, depending on the refresh rate the game uses.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by SuperBabyHix »

Question, did the Lynx have a refresh rate that varied constantly throughout gameplay (like modern VRR?) or just each game could run at a different, constant, rate?
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

FPGAzumSpass wrote: Tue Mar 02, 2021 5:30 am
LamerDeluxe wrote: Mon Mar 01, 2021 10:12 pm The only other thing I saw was a very slight seam in the ground scenery of Blue Lightning. That might even be there on a real Lynx, but I never noticed it.
The way the Lynx works it could happen if the developers don't do the double buffering right, but more likely it's the core currently.

The beta core is not synchronized to video output currently, just outputting 60Hz.
So you have tearing from time to time, depending on the refresh rate the game uses.
It wasn't screen tearing, but a slight seam between two of the perspective (scaled, skewed and tapered) ground patch sprites, they didn't line up perfectly on the side.

It will be great when you have the variable frame rate output working.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

SuperBabyHix wrote: Tue Mar 02, 2021 12:18 pm Question, did the Lynx have a refresh rate that varied constantly throughout gameplay (like modern VRR?) or just each game could run at a different, constant, rate?
AFAIK it is constant per game. Though it would be possible to change it between different in-game scenes/screens.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by SuperBabyHix »

That's really interesting. Thanks.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FPGAzumSpass »

Unfortunatly there are games which change it frequently, e.g. California games is 75Hz in Intro and Mainmenu, but 60 Hz in the games.
Also games frequently shut off the output for a while.

So i don't really see a possibility for free sync, this will most likely not be supported by any displays.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

FPGAzumSpass wrote: Wed Mar 03, 2021 3:47 pm Unfortunatly there are games which change it frequently, e.g. California games is 75Hz in Intro and Mainmenu, but 60 Hz in the games.
Also games frequently shut off the output for a while.

So i don't really see a possibility for free sync, this will most likely not be supported by any displays.
The thing with the Lynx is that you don't notice the frequency changes at all on the device itself. It makes sense to change the frequency between the game-play and other parts.

I remember reading something about shutting off the output to save battery life. I have monitors that can handle 75Hz or even higher at certain resolutions, so I hope that can be supported.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FPGAzumSpass »

I guess there could be 75Hz output just as 60Hz is currently, but most likely you need to select it in OSD.

My problem is, that my Monitors don't support it at all. I assumed they could at lower resolution, but it seems they cannot.
So i cannot test that currently just as analog output.

Also it get's kind of annoying already to support all those output modes....
Every mode needs to be implemented seperate. Currently there is already:
- 160*102
- 102*160
- 102*160 - 180° rotated. (yes some games do Tate mode other direction as other games)

I will add 240p next, only in landscape mode for now, i already see bug reports for 240p not supporting Vertical orientation ;)

Adding 75Hz then will effectivly double the amount of modes, then next comes 50Hz(used e.g. by Lemmings)...


I would rather work on core internals...maybe someone can help out who has CRT and display supporting 75Hz.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

FPGAzumSpass wrote: Thu Mar 04, 2021 5:44 am I guess there could be 75Hz output just as 60Hz is currently, but most likely you need to select it in OSD.

My problem is, that my Monitors don't support it at all. I assumed they could at lower resolution, but it seems they cannot.
So i cannot test that currently just as analog output.

Also it get's kind of annoying already to support all those output modes....
Every mode needs to be implemented seperate. Currently there is already:
- 160*102
- 102*160
- 102*160 - 180° rotated. (yes some games do Tate mode other direction as other games)

I will add 240p next, only in landscape mode for now, i already see bug reports for 240p not supporting Vertical orientation ;)

Adding 75Hz then will effectivly double the amount of modes, then next comes 50Hz(used e.g. by Lemmings)...


I would rather work on core internals...maybe someone can help out who has CRT and display supporting 75Hz.
Wow, that is a lot of modes already. I could help with testing on CRTs and 75Hz displays. I really don't like Patreon though, so if I could sponsor you directly, I'd much prefer that.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FPGAzumSpass »

Don't worry the core will be public in a few weeks anyway.
I fear that testing alone will make for some long iteration cycles, will tackle 240p for CRT first now.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by Moondandy »

What is the folder name so we can get our roms prepped and ready?
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by evilsim »

/media/fat/games/Jaguar is where I was using an older beta core from once before. Should be the same.
I have a boot.rom in the folder too.

I am keen for the public release of this one :)
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by tontonkaloun »

Moondandy wrote: Thu Mar 04, 2021 4:35 pm What is the folder name so we can get our roms prepped and ready?
/media/fat/Games/Lynx
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by Moondandy »

Thanks mate!
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by werpu »

Gave it a quick run... love this core
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by SegaSnatcher »

Played around with this core yesterday, pretty neat little system.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by LamerDeluxe »

Imagine this as a handheld in 1989, the same year the original Gameboy came out. It was revolutionary, it can do things Amigas can't do. But with the hardware being designed by people also responsible for designing the Amiga hardware, that isn't really a surprise.

All the graphics you see on screen are (scaled/stretched, skewed, tapered, run-length encoded) sprites (even the backgrounds) of almost unlimited size (511 x unlimited) and of an amount only limited by memory. They are just a linked list of sprites anywhere in memory, drawn in that order. The sprites are actually more like blitter objects. There is no tiling hardware.

They are placed in a virtual 32K x 32K 'world' and then the screen is placed somewhere within this world to draw the desired view.

The Lynx can also draw lines and filled polygons. This is done by correctly distorting a single pixel sprite.

The graphics chip (Suzy) can also be used for multiply and divide calculations, combined with add/subtract, of two 16-bit numbers, with a 32-bit result. This happens in parallel to the CPU.

There are vertical and horizontal blanking interrupts, so you can change things per scan line, mostly used to change colors, for sky gradients, or to have more than 16 colors on screen at once.

The Lynx has four channels of enhanced Atari-style sound (semi-random square or delta waves, for pure, buzzer or noise sounds), or eight bit audio samples, which can be streamed (compressed if needed) from the cartridge. The Lynx 2 has stereo audio (through the headphone output) with variable stereo panning for each channel.

The full 64KB of memory can be used (the custom chip addresses can be switched out of memory addressing). Data from the cartridge is loaded, not switched into a memory range, unlike how many other systems worked.

The multi-player hardware limitation (performance-wise) is 15 players, using ComLynx cables. The commercial game supporting the most simultaneous players is Slime World, with up to eight players.

Battery life of the Lynx is about 5 hours, which isn't too bad, but rechargeable batteries weren't great at the time and it used six AA batteries. A power supply was used a lot.

The display is backlit, with 16 out of 4096 colors (or more with horizontal blanking interrupts), it is washed out and has a lot of motion blur. Atari sold an official Sun Visor to play outside, that folds up as a display protector and looks really cool.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by FoxbatStargazer »

For those who haven't subbed, v2 beta has a ton of new features: sound, hardware collision detection, vertical rotation, doubled resolution for analog output. Everything seems to play great and it looks very close to releasable.
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Re: New Atari Lynx Core coming for MiSTer FPGA

Unread post by dmckean »

Doubled resolution for analog output sounds really nice. Anyone have a video of what this looks like?
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