EverDrive N8 alleged mapper inaccuracies

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Konata Izumi
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Konata Izumi » Mon Mar 23, 2020 8:30 am

Hello, I'm the user who made that list (I should probably update my username sometime, this is a very old account :P), and I'd like to clear up a few things that I didn't clarify in that list prior to posting. (that's being tired at 2AM for ya)

First up, the 50MHz oversampling statement. This is actually a concern since the internal microcontroller/FPGA can lag pretty hard sometimes, for reasons that I do not know (Occurs very rarely in Gimmick, but some test ROMs can make it chug pretty hard.)

Secondly, let me correct this statement:
N8 Pro spams $00 writes to DPCM, leading to lots and lots of DPCM bugs.
This does indeed happen, but it's only when the N8 Pro's NSF player is running. Can't figure out why either, but my guess is that it happens to be an implementation issue.

Finally, for anything related to mapper expansion sound, I am able to provide recordings of the N8's sound using either commercial or test ROMs, provided they fit under the original N8's 512K PRG/CHR limit.
Memblers wrote:
Sun Mar 22, 2020 4:05 am
I have a Famicom EverDrive (older version), and the expansion audio has problems. It's there, but it's almost entirely drowned out by the 2A03. Impedance mismatch or something? It's my only complaint with this otherwise great cart, though. It's worth knowing, if one wants to get an FC version for whatever reason. Hopefully fixed in the Pro, I don't know.
The original N8 has a feature to let you set the expansion sound's mixing volume. Don't know how this happened all of a sudden, but it's a welcome update with the new OS (I didn't see it in the prior updates).


Additionally, I noticed that if the cart detects a specific game that uses bus conflicts, it'll try and emulate the desired conflict, although support for this is very limited, and it doesn't always work.

Pokun
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Pokun » Tue Mar 24, 2020 2:43 am

Konata Izumi wrote:
Mon Mar 23, 2020 8:30 am
Memblers wrote:
Sun Mar 22, 2020 4:05 am
I have a Famicom EverDrive (older version), and the expansion audio has problems. It's there, but it's almost entirely drowned out by the 2A03. Impedance mismatch or something? It's my only complaint with this otherwise great cart, though. It's worth knowing, if one wants to get an FC version for whatever reason. Hopefully fixed in the Pro, I don't know.
The original N8 has a feature to let you set the expansion sound's mixing volume. Don't know how this happened all of a sudden, but it's a welcome update with the new OS (I didn't see it in the prior updates).
There was a volume mixing setting in older OS versions (apparently removed in OS v1.14), but the problem was that it didn't really make any difference, expansion audio was still drowned out. Probably due to the lack of the op-amp as Nai said.
I haven't tried the latest OS version though.

Great Hierophant
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Great Hierophant » Wed Mar 25, 2020 10:48 am

If we go down this road, we could also complain that the EverDrives have rather out of date mapper support. Seven licensed mappers, 153, 155, 157, 159, 210, 547 and 552 are not supported or are conflated into other mappers like 1, 16 and 19.

The EverDrive only supports Galaxian by CRC values, not by the alternate ROM size designation. That breaks any hack of the game which does not double up on the PRG.

Mapper 64 needs work with its IRQ counter.

I am uncertain whether the four screen mirroring flag works outside mappers 1 and 4. The only licensed games which support true four-screen mirroring use mappers 4, 77 and 206.
Last edited by Great Hierophant on Thu Apr 30, 2020 9:46 pm, edited 1 time in total.

Great Hierophant
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Great Hierophant » Thu Mar 26, 2020 9:31 am

Pokun wrote:
Tue Mar 24, 2020 2:43 am
Konata Izumi wrote:
Mon Mar 23, 2020 8:30 am
Memblers wrote:
Sun Mar 22, 2020 4:05 am
I have a Famicom EverDrive (older version), and the expansion audio has problems. It's there, but it's almost entirely drowned out by the 2A03. Impedance mismatch or something? It's my only complaint with this otherwise great cart, though. It's worth knowing, if one wants to get an FC version for whatever reason. Hopefully fixed in the Pro, I don't know.
The original N8 has a feature to let you set the expansion sound's mixing volume. Don't know how this happened all of a sudden, but it's a welcome update with the new OS (I didn't see it in the prior updates).
There was a volume mixing setting in older OS versions (apparently removed in OS v1.14), but the problem was that it didn't really make any difference, expansion audio was still drowned out. Probably due to the lack of the op-amp as Nai said.
I haven't tried the latest OS version though.
I found that the mixer in OSv20 and above just was not going to match volumes with an older Famicom or Twin Famicom, but newer Famicoms and the AV Famicom should be able to get a proper balance in the most common cases.

I guess the VRC7 core was never updated to reflect the discovery of the exact patch dump.

The new FDS core just displays a blue screen with "Please Set Disk Card" in White Text. I assume Krikzz no longer used the original Nintendo introduction screen to avoid incurring the wrath of the big N. But I also assumed that the underlying BIOS code was still being used. It would be nice to be able to use a dump of the FDS BIOS, krikzz had hooks into the original to get it to do things it was not designed to do like automatic disk swapping.

The EverDrive N8 Pro looks to be a very capable canvas and the development tools appear to be open source, if a bit out of date.

Pokun
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Pokun » Fri Mar 27, 2020 3:24 am

A lot of those mappers are even listed as "not exist" on the Everdrive's mapper map.

Galaxian would need Nes 2.0 I guess, which the Everdrive doesn't support. Considering that Nes 2.0 had not been entirely defined yet and has been changing a lot I can't really blame the Everdrive though. Hopefully support will come though.

By newer Famicom I guess you mean the HVC-GPM-xx boards? I think HVC-CPU-06 and HVC-CPU-07 are among the most common Famicom boards. That's bad news anyway, I have a CPU-07 myself.

So that's how automatic disk swapping works. Yeah it would be better if the user would be able to provide a clean BIOS dump. There's no telling if a game relies on the BIOS being exactly in a certain way. Developers do that all the time for other systems even if they are not supposed to. For example PC Engine games that hardcodes the address to a BIOS call on the CD System Cards instead of using the jump table as it's supposed to (and therefore the games doesn't work on newer or English System Cards).

Great Hierophant
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Great Hierophant » Fri Mar 27, 2020 7:27 am

Pokun wrote:
Fri Mar 27, 2020 3:24 am
By newer Famicom I guess you mean the HVC-GPM-xx boards? I think HVC-CPU-06 and HVC-CPU-07 are among the most common Famicom boards. That's bad news anyway, I have a CPU-07 myself.

So that's how automatic disk swapping works. Yeah it would be better if the user would be able to provide a clean BIOS dump. There's no telling if a game relies on the BIOS being exactly in a certain way. Developers do that all the time for other systems even if they are not supposed to. For example PC Engine games that hardcodes the address to a BIOS call on the CD System Cards instead of using the jump table as it's supposed to (and therefore the games doesn't work on newer or English System Cards).
Yes, old Famicom are HVC-CPU-xx, new Famicom are HVC-GPM-xx and HVCN-CPU-xx (AV Famicom)

Could you provide examples of PC Engine CD games which require an old CD System Card?

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rainwarrior
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Re: EverDrive N8 alleged mapper inaccuracies

Post by rainwarrior » Fri Mar 27, 2020 10:09 am

Great Hierophant wrote:
Fri Mar 27, 2020 7:27 am
Could you provide examples of PC Engine CD games which require an old CD System Card?
I dunno if this is quite the kind of example you're looking for but Rondo of Blood had a tiny playable demo that only appeared with an older BIOS.

https://www.youtube.com/watch?v=lFJv_GJJGBc

Pokun
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Pokun » Fri Mar 27, 2020 10:36 am

Ah no that's not what I was talking about. Many Super CD games detects the System Card version and refuses to start if it's not a Super System Card. Rondo just takes it further and runs a joke game. I was talking about games that doesn't work because of oversights of the developers, that BIOS content can change in newer versions.


According to my notes: A Ressha de Ikou III, Bonanza Bros and Alshark all breaks on the English Super System Card. Then there's the CD version of Juuouki (Altered Beast) that only works on the very first System Card 1.0 which is Japan-exclusive (but works on non-Japanese systems with a pin-adapter). A later version of the game should work on any card though.

A Ressha de Ikou III makes hardcoded BIOS calls instead of using the vectors at the beginning of the System Card ROM like it's supposed to. The English System Cards have things moved around to make room for the English menu data, so the BIOS calls fails.

Bonanza Bros checks the version number and expects v3.0 exactly. The English version of the Super System Card returns v3.1 so the game detects it as a normal CD System Card (as opposed to Super CD).

The problems in Alshark is unknown according to my notes, and I don't know the bug in Juuouki either. The buggy Juuouki has the serial HA10817 and the working version is HA10109.

Great Hierophant
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Re: EverDrive N8 alleged mapper inaccuracies

Post by Great Hierophant » Tue Jun 02, 2020 10:29 pm

Some of these issues I have concerns or questions about :
  • Bus conflicts don't work, anything relating to the hardware relying on it just doesn't function correctly.
They can work and do work for Cybernoid or are at least avoided on the N8 Pro for that game. On the N8 the bus conflict in that game leads to CHR corruption, on the N8 Pro you can switch from music to sound effects and back as much as you like and not trigger the bus conflict. I do not know of any other game where bus conflicts will affect its ability to perform correctly.
  • Modulation is broken, sometimes it tries to work, but doesn't.
This may have been fixed in more recent firmwares for the N8 Pro, sound effects that use modulation as in Metroid's door opening and closing consistently work.

VRC7:
  • Patches use approximations of the real chip, so anything using the expansion audio doesn't work by default.
I do not understand what this is supposed to mean. I think they updated to the VRC7's correct dumped/extracted patches for the N8's OSv1.20. Even the approximated patches will permit the expansion audio to work, even if they may not sound completely accurate. Lagrange Point sounds decent enough.

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