C64 Core

https://github.com/MiSTer-devel/Main_MiSTer/wiki

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Sorgelig
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Re: C64 Core

Postby Sorgelig » Mon Dec 23, 2019 5:53 am

Since all these games have disk version, i don't see a big reason to make C64 more complicated bringing backup save load just for couple games.

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Re: C64 Core

Postby Mills » Wed Dec 25, 2019 10:37 am

Anyone got the cartridge version of "mayhem in monsterland" working?

It loads ok, but then it waits for you to press some key or something to select game or intro. I hit every key on the keyboard, mouse or gamepad button, and nothing happens.

EDIT: is is solved in last update (C64_20191221.rbf) :D .

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Re: C64 Core

Postby Pupil » Mon Dec 30, 2019 9:02 am

anyone know where the RUN/STOP key would be mapped on a modern keyboard for C64?

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Re: C64 Core

Postby knc » Mon Dec 30, 2019 9:16 am

Pupil wrote:anyone know where the RUN/STOP key would be mapped on a modern keyboard for C64?

It is ESC key normally

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Re: C64 Core

Postby Pupil » Mon Dec 30, 2019 1:56 pm

knc wrote:
Pupil wrote:anyone know where the RUN/STOP key would be mapped on a modern keyboard for C64?

It is ESC key normally


Yeah you're right. It turns out my Esc key is not functioning on that keyboard. Confirmed with a different keyboard.

Thanks!

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Re: C64 Core

Postby seastalker » Sun Jan 26, 2020 1:00 am

I'm planning a project build and am hoping to not be wasteful in spending on things I may already have. I have some extra C64 breadbin cases and keyboards, a keyrah, and considering my options for my Mister (and Mist).

As of January of 2020, how would one compare the C64 Mister and/or Mist cores to that of the Ultimate 64 board, or the Cartridge based solutions of the Turbo Chameleon or ULTIMATE-II+ in terms of strictly C64 accuracy and features? I support many of these projects and am not looking to start arguments. I have a MKII Reloaded board, original C64c, but I only have the SD solution and neither of the mentioned carts yet.

Has either one of the Mister or Mist cores surpassed the other or are they basically the same? In my scenario, are there any features (write support, load all file types, etc.) yet implemented in either core that might make me consider the cost of pre-ordering one of the carts or U64 board vs. doing a Mister + keyrah (either internally in a breadbin or externally via USB)?

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Re: C64 Core

Postby Sorgelig » Sun Jan 26, 2020 8:11 am

Probably, tests alone will be helpful for the future improvements.
It would be more helpful if there will be actual patches to fix the problems in this core.

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Re: C64 Core

Postby drj3rk » Tue Feb 04, 2020 7:54 pm

This is purely curiosity. I design analog circuits (for synthesizers) and I do not code, so I don't know too much about what happens behind the scenes with all of these MiSTer cores. I do understand how programmable logic works, but I've only designed some simple CPLD logic circuits (once again for audio applications, like shift register sequencers and things), and even then I use the schematic based tools.

Anyway, I was curious how the SID's filter is simulated on MiSTer. Is it possible to do an advanced simulation of the analog filter using the ARM processor, and route the oscillators and noise through that as necessary? I'm not suggesting that anyone take that on necessarily since I couldn't do it myself. I'm more just wondering if it's already handled like that, or how it's actually handled.

I'll go look around, and see if I can find some more information myself, but thought I'd ask here anyway.

:cheers:

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Re: C64 Core

Postby rsn8887 » Wed Feb 05, 2020 12:03 am

Sorgelig can probably give a more informed answer, but I don't think you would want to do the filter emulation on the ARM part. AFAIK, FPGA architecture lends itself very well to signal processing and filtering. So you would probably want to implement the filter emulation on the FPGA itself. I think there's already some implementation of the SID filter in the C64 core. Maybe it could simply be improved.

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Re: C64 Core

Postby drj3rk » Wed Feb 05, 2020 12:08 am

rsn8887 wrote:Sorgelig can probably give a more informed answer, but I don't think you would want to do the filter emulation on the ARM part. AFAIK, FPGA architecture lends itself very well to signal processing and filtering. So you would probably want to implement the filter emulation on the FPGA itself. I think there's already some implementation of the SID filter in the C64 core. Maybe it could simply be improved.


Thanks for the reply. I'm not necessarily saying anything needs to be improved, changed, etc. I was just curious how it's implemented, and whether something like that could be beneficial or not. More of a conceptual question really. There are some fairly CPU intensive filter emulations out there for the SID chip, and I was just curious if those could in theory be ported to run on the ARM if it wasn't doing much while the C64 is being simulated.

I actually don't have any complaints with the current implementation. The thought just occurred to me, and I haven't read anything on how it is actually implemented.

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Re: C64 Core

Postby Sorgelig » Wed Feb 05, 2020 5:39 pm

FPGA can do math quite effectively. And there is no reason to use ARM for that - it will be less effective than FPGA does. Actually filters math is not so hard. The problem is to know the correct formula. Then filter becomes a set of -,+,/,* operations - all of them are available in FPGA either directly or through DSP blocks.
Problem is not in resources but in correct implementation.

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Re: C64 Core

Postby drj3rk » Wed Feb 05, 2020 6:22 pm

Sorgelig wrote:FPGA can do math quite effectively. And there is no reason to use ARM for that - it will be less effective than FPGA does. Actually filters math is not so hard. The problem is to know the correct formula. Then filter becomes a set of -,+,/,* operations - all of them are available in FPGA either directly or through DSP blocks.
Problem is not in resources but in correct implementation.


Nice! That answers that question. I've designed plenty of analog filters, but have never done it digitally. I guess the math would be about the same, but that isn't my strongest skill. :lol: I cheat and use transform function calculators and things like that. Anyway, thanks for taking the time to explain it.

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Re: C64 Core

Postby richx » Thu Feb 06, 2020 2:47 am

drj3rk wrote:Nice! That answers that question. I've designed plenty of analog filters, but have never done it digitally. I guess the math would be about the same, but that isn't my strongest skill. :lol: I cheat and use transform function calculators and things like that. Anyway, thanks for taking the time to explain it.


The FPGA could be used for just the well understood digital portion of the SID, and the analog portion of the SID implemented outside the FPGA with analog components/filters on add-on board to get the more complex analog/filter "calculation" for "free".. Not sure how close it would sound to the original, but the most "true" (and cool) re-implementation..

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Re: C64 Core

Postby drj3rk » Fri Feb 07, 2020 6:40 pm

richx wrote:
drj3rk wrote:Nice! That answers that question. I've designed plenty of analog filters, but have never done it digitally. I guess the math would be about the same, but that isn't my strongest skill. :lol: I cheat and use transform function calculators and things like that. Anyway, thanks for taking the time to explain it.


The FPGA could be used for just the well understood digital portion of the SID, and the analog portion of the SID implemented outside the FPGA with analog components/filters on add-on board to get the more complex analog/filter "calculation" for "free".. Not sure how close it would sound to the original, but the most "true" (and cool) re-implementation..


An analog filter module project would be fun! It could be controlled via simple DAC.

A friend and I actually had plans of designing a new SID chip (digital with fancier analog filter) that's pin-compatible with the SID. It would be similar to say one of the Ensoniq keyboards (SQ-80 perhaps) that used the DOC chip and a CEM analog filter.

The SID is super charming, so it's not like it needs a replacement, we just thought it would be fun. :lol:

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Re: C64 Core

Postby Sorgelig » Sat Feb 08, 2020 3:17 am

Once analog circuit will be known, it won't take long to get a math of it and thus implemented in FPGA form. There is no point to make it in analog. Controlled filter needs the way to control, so it means it needs a digital part like special register to change the filter parameters. So you can't simply add analog filter - you will need to add a digital part too.

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Fun discovery with mister c64 core terminal

Postby Funnybones » Sun Feb 23, 2020 10:09 pm

So I was playing with the uart functionality on the c64 core using CCGMS 2017 and I noticed that the ATHELP command lists an AT command called ATMP3 that says it plays an MP3.

I ran the command and it reported that /media/fat/mp3 was not found, so I created the folder and copied an mp3 in.

When I ran it again it showed my mp3 and prompted me to select a number to play.

It then proceeded to play my mp3.

How awesome is that. you can listen to MP3's while BBS'ing.

I googled around for any mention of this and found nothing so thought I'd share.

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Re: Fun discovery with mister c64 core terminal

Postby Coffea » Mon Feb 24, 2020 2:54 am

Sounds like cheating if you ask me ... BBS's should only work with music on Tape/LP.


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