Carnivore2 : First impressions and bugs...

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By Alexey

Guardian (1653)

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21-04-2018, 22:11

Good news! I finally managed to complete the boot block with the support for Turbo/R800 mode switching and preserving this mode as well as the selected VDP frequency for ROMs after system restart. This won't work for configuration entries though. Currently the new boot block as well as the updated firmware are being tested. You will not need to update the firmware to enable the new features in the boot block, the firmware got only some unrelated minor bugfixes.

By Alexey

Guardian (1653)

Alexey's picture

23-04-2018, 16:11

Also in the works is the feature that was proposed by Carmeloco - when a ROM file is being loaded into FlashROM or RAM, the RCP file with the same name will be found and used. This will remove the need to manually load RCP files if certain ROMs don't work with default settings.

By Alexey

Guardian (1653)

Alexey's picture

24-04-2018, 18:47

Another news - we may be close to making a firmware that will allow IDE to work correctly regardless of the CPU speed. In any case in a few days there will be a big release for Carnivore2.

By Pencioner

Hero (653)

Pencioner's picture

25-04-2018, 01:23

Alexey wrote:

Another news - we may be close to making a firmware that will allow IDE to work correctly regardless of the CPU speed. In any case in a few days there will be a big release for Carnivore2.

That will rock, i hope you will make this possible, it would be really great improvement!

By sdsnatcher73

Master (193)

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25-04-2018, 17:34

Hey Alexey, a question. In default configuration the Carnivore2's SCC chip seems to be configured as K051649 (the original SCC) and is detected as such in VGMPLAY. The MegaFlashRAM SCC+ SD's SCC chip is configured as K052539 (the SCC in the Snatcher and SD-Snatcher carts) and is detected as such in VGMPLAY.

I know a SCC+ RCP exists (which I believe also includes the 128kB RAM, from both the Snatcher and SD-Snatcher carts) but then you don't have the other features of C2. My question is would it be possible to create an RCP based from the default where the SCC chip as a K052539 without the additional RAM and in a subslot? In a similar manner as the MFR SCC+ SD...

By Alexey

Guardian (1653)

Alexey's picture

25-04-2018, 17:57

The SCCPLUS.RCP file configures the cartridge without additional RAM. So in this mode you can only use the cartridge as a sound card in a non-expanded slot. I can make the RCP file so that the RAM is also enabled, but then the slot will need to be expanded. I am not 100% sure that the games will like SCC+ in the expanded slot. But if you could test that, it would be great.

By sdsnatcher73

Master (193)

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25-04-2018, 19:23

Well actually what I would like is same as default config but scc replaced by scc+

And the RAM i meant was the RAM from the Snatcher cart, that is in the same slot and i believe it has to be there in sccplus.rcp because sd-snatcher recognizes c2 as it would the original cartridge. As you know the original carts had 64kB but in different positions for both games so the cart would only work for the game it was sold with. But you could expand it to 128kB and it would then work for both games.

By Alexey

Guardian (1653)

Alexey's picture

25-04-2018, 23:35

Sorry, I am not sure what you mean. I have no idea how the original Snatcher cartridges look and work. I tried the Snatcher game with SCCPLUS.RCP and it worked fine. Please describe the problem a bit differently so that I could understand.

By sdsnatcher73

Master (193)

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26-04-2018, 06:22

The problem is in the type of the SCC chip (in FPGA) for default configuration (so IDE+RAM+FMPAC+SCC) in C2. At least that is my conclusion from playing with VGMPLAY yesterday. So here is what I did and how you could reproduce:

I downloaded the SD-Snatcher and Nemesis 3 musics from vgmrips:
http://vgmrips.net/packs/pack/sd-snatcher-msx2
http://vgmrips.net/packs/pack/nemesis-3-the-eve-of-destructi...

On vgmrips.net you can see the soundchip used by the songs, for SD-Snatcher it is AY-3-8910 (PSG) and K051649 (original SCC), for SD-Snatcher it is AY-3-8910 (PSG) and K052539 (the SCC+).

Now playing these back with VGMPLAY on C2 (I just used the first file here), for SD-Snatcher it sees the K052539 chip in the VGZ file but has no corresponding playback chip. So only PSG output:

When I play first file from Nemesis 3 set on C2 it shows K051649 in source file and does detect the C2 as Konami SCC and I get both PSG and SCC sound:

Doing the same thing on the MFR SCC+ SD VGMPLAY will detect the chip in the FPGA as Konami SCC+:

And because SCC+ is backward compatible to SCC Nemesis 3 file also plays fine:

At least the SCC chip implemented in FPGA with C2 in default config is a K051649 original SCC.

By sdsnatcher73

Master (193)

sdsnatcher73's picture

26-04-2018, 09:12

Actually I just tested with following setup:
- OneChipMSX with C2 in slot 1
- OneChipMSX internal SCC+ disabled (slotmode /0)
- C2 in SCC+ mode with SCCPLUS.RCP

In this config VGMPLAY can also not detect the C2 SCC as a SCC+. So it seems the SCC logic in C2 is that of an original SCC and not an SCC+ (or VGMPLAY can't detect it correctly). VGMPLAY does detect SCC+ on MFR and OCM so not sure what the difference is compared to C2.

Here is some info on the original Snatcher/SD-Snatcher cartridges:
http://bifi.msxnet.org/msxnet/tech/soundcartridge

If the FPGA logic is the same as OCM/MFR it may just be different initialization in boot block??

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