Atari 2600 / VIC 20

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SchneiderCPC664
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Atari 2600 / VIC 20

Postby SchneiderCPC664 » Wed Aug 15, 2018 6:28 am

With every update of the MIST cores they are come closer to the original hardware.
But there are some cores whithout development quite a long time. Some of my favorite Atari 2600 games are not working (Millipede,..) and Vic-Man/Snakman is not running on the VIC20 core.
Is there a chance for further development on these cores in the near future?

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Re: Atari 2600 / VIC 20

Postby RobeInie » Wed Aug 15, 2018 11:49 pm

Atari 2600 is my favourite console,
The core is OK for some games, but as far I know it only accepts simple bank switch and there are some undocumented instructions (I think) , so some carts will not work (Pitfall 2 , Popeye ...)

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Re: Atari 2600 / VIC 20

Postby slingshot » Thu Sep 13, 2018 10:15 am

A new VIC-20 core is here:
https://github.com/gyurco/VIC20_MiST/

Binary release:
https://github.com/gyurco/VIC20_MiST/releases

I've just wanted to add 1541 support to the old core, but it ended up in a complete rewrite. CRT support is not added yet, I found everything as .PRG. But if you show me a relevant .CRT collection, I'll add it.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Thu Sep 13, 2018 12:22 pm

Very excellent port !

But if you can add CRT support it would be better because there are many games released only in cartridge format as Atari ones.
Examples are: Jungle Hunt, MS PacMan, Moon Patrol, etc...

Also Frogger 07 (16k) doesn't work.

May you add an NTSC option ? Some cartridges games are only in this format.

Thanks a lot for this new updated core :cheers:

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Re: Atari 2600 / VIC 20

Postby MasterOfGizmo » Thu Sep 13, 2018 2:31 pm

Excellent! This was the first computer i owned and this is now the first time i have used a floppy disk with it. Very funny ... I just sent you a PR with YPbPr support for it.

I haven't yet managed to use the CRT support. But that may be because it's a WIP ...

Anyway, great work!
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Re: Atari 2600 / VIC 20

Postby slingshot » Thu Sep 13, 2018 3:31 pm

DanyPPC wrote:Very excellent port !

But if you can add CRT support it would be better because there are many games released only in cartridge format as Atari ones.
Examples are: Jungle Hunt, MS PacMan, Moon Patrol, etc...


Where can I get these CRT files? I found only PRG-s everywhere (possibly these are also available as PRG).

I admit, the only d64 game I tried is VicDoom, but I'll check others.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Thu Sep 13, 2018 5:18 pm

I give you them via pm, all selected from me :angel:

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Thu Sep 13, 2018 5:26 pm

Hope my help is useful.

if you can even make the megacart work it would be infinitely beautiful !

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Re: Atari 2600 / VIC 20

Postby desUBIKado » Thu Sep 13, 2018 6:25 pm

Thank you very much for this port.

Could you make VIC20 folder as default folder for .PRG and .D64 loading?

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Re: Atari 2600 / VIC 20

Postby MasterOfGizmo » Thu Sep 13, 2018 6:29 pm

desUBIKado wrote:Could you make VIC20 folder as default folder for .PRG and .D64 loading?


It already is. That's nothing the core does itself. It's the io controller (the part running the MIST firmware) that automatically searches under the name of the running core.
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Re: Atari 2600 / VIC 20

Postby desUBIKado » Thu Sep 13, 2018 7:42 pm

MasterOfGizmo wrote:It already is. That's nothing the core does itself. It's the io controller (the part running the MIST firmware) that automatically searches under the name of the running core.

In my case, the core goes to the root folder. In contrast, C16 or fpga64 cores go to folders C16 and C64 respectively

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Re: Atari 2600 / VIC 20

Postby slingshot » Thu Sep 13, 2018 8:21 pm

DanyPPC wrote:I give you them via pm, all selected from me :angel:

Got them!
As I suspected, they're just .prg files with a different extension. Just have to press reset after loading them to run. Maybe I can add auto-reset if desired.

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Re: Atari 2600 / VIC 20

Postby DrOG » Fri Sep 14, 2018 4:00 am

DanyPPC wrote:...
if you can even make the megacart work it would be infinitely beautiful !

If you need, here's the megacart ROM (download all files to the same folder, remove the .ZIP extensions, and double click on the .CRC file in Total Commander, or you may use HJ-Split as well: http://www.hjsplit.org/ )
Sorry to be so difficult, but otherwise the forum motor doesn't let me to upload this big file.
You do not have the required permissions to view the files attached to this post.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Fri Sep 14, 2018 5:43 am

Thanks DrOG, i have just send the megacart.rom to slingshot.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Fri Sep 14, 2018 5:58 am

slingshot wrote:As I suspected, they're just .prg files with a different extension. Just have to press reset after loading them to run. Maybe I can add auto-reset if desired.


Ok, i saw, they work with 8K Rom enabled option + Reset-

And what about splitted cartridges like Moon Patrol or Jungle Hunt ?
How can i load this kind of games rom ?

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Re: Atari 2600 / VIC 20

Postby slingshot » Fri Sep 14, 2018 7:21 am

DanyPPC wrote:
And what about splitted cartridges like Moon Patrol or Jungle Hunt ?
How can i load this kind of games rom ?


No idea, how do you load it in an emulator? Since it loads into 2 non-continuous address spaces, automatic loading is not really possible. I think they're just a dump of the ROM chip inside the cartridge, but the internal address-decoding logic is missing.
But if they're in two separate file, then it's easy: load them after each other.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Fri Sep 14, 2018 7:35 am

In the old Vic20 Core there is an option to load this kind of cartridges, from the readme in repository:
Multipart cartridges:
To run multipart crt's turn on "CRT with load address:yes" and load the lower part first.
Use the Tosec crt's without the [a] as those have the load address removed. Load the $4000 or $6000
part first and then the $A000 part. The $A000 crt will trigger a reset and starts the game.

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Re: Atari 2600 / VIC 20

Postby slingshot » Fri Sep 14, 2018 7:42 am

DanyPPC wrote:In the old Vic20 Core there is an option to load this kind of cartridges, from the readme in repository:
Multipart cartridges:
To run multipart crt's turn on "CRT with load address:yes" and load the lower part first.
Use the Tosec crt's without the [a] as those have the load address removed. Load the $4000 or $6000
part first and then the $A000 part. The $A000 crt will trigger a reset and starts the game.


I've already added the CRT extension to the core, but carts with 16k size will not work anyway. With two 8194 bytes file, it's OK. Also added support to load without load address in the file, but that is fixed to $a000 in this case.

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Fri Sep 14, 2018 9:16 am

Ok, i tested new core 20180914, but I cannot figure out how to load multipart games. I use the same procedure of the old Vic20 Core but no way.
With old core they work, load the first part and then the second part with A000 address, and the cartridge works.

Is it possibile to add an NTSC option for those standard NTSC games ?

Have you tested Frogger '07 (16k) ?
It doesn't work even with old core.
Maybe it uses a few hardware tricks.

Anyway thanks for your efforts :cheers:

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Re: Atari 2600 / VIC 20

Postby slingshot » Fri Sep 14, 2018 10:18 am

First load the $6000 part, then the $a000 part. As I see, CRT with load address should be Yes in both cases, all crts and prgs have a load address included. And don't forget to enable RAM/ROM at the appropriate places, $6000 requires the 24k extension enabled.

NTSC and the Frogger is a matter of the VIC chip which is not my work, and I'm not familiar with it. Maybe I'll dig myself into it, but don't want to spend days of debugging with that.

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Re: Atari 2600 / VIC 20

Postby MasterOfGizmo » Fri Sep 14, 2018 1:46 pm

I spent a few hours with the VIC20 m6561 VIC chip. I made two small changes (already submitted to slingshot for inclusion) which greatly increase demo compatibility. Many great demos now run pretty good.

I think there are also some problems with memory mapping left like which memory mirrors where especially on unexpanded setups.
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Re: Atari 2600 / VIC 20

Postby slingshot » Fri Sep 14, 2018 2:29 pm

MasterOfGizmo wrote:I spent a few hours with the VIC20 m6561 VIC chip.

Did a new release with your patches, now even this Frogger game is mostly correct!

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Re: Atari 2600 / VIC 20

Postby DanyPPC » Fri Sep 14, 2018 3:26 pm

Guys, you are incredible !!! :cheers:

Tested many crt and these work.
There is only Tutankham where i no get control, Bandits NTSC and Squish'em where there are some scrolling lines over the screen, but i think due to NTSC standard.


Very, very GOOD update.
Excellent work !

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Re: Atari 2600 / VIC 20

Postby Chris23235 » Fri Sep 14, 2018 4:00 pm

Many many many thanks, Gridrunner and Matrix work properly, both didn't work with the old core.

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Re: Atari 2600 / VIC 20

Postby Higgy » Fri Sep 14, 2018 5:52 pm

This rapid fire development/improvement is great to see.

Great work everyone :cheers:


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