Need advice buying a NES-101 and a flash cart

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

Moderator: Moderators

Post Reply
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Need advice buying a NES-101 and a flash cart

Post by WedNESday »

Hello everyone! I'm back after an absence of quite a few years now but this time I'm back for good. I won't bore you with the details of why I've been away and what I've been up to but I will say this... if a big tall guy with a huge scar on his face comes around asking after me, you don't know who I am, ok? :oops:

Moving on to the actual topic itself, I recently decided to give becoming a freelance HTML, CSS & JavaScript programmer a try. I registered my own domain name last year and have been working on porting all of my C++ projects over to JavaScript. This includes (of course) WedNESday. I'll be releasing it fairly soon for you guys to give a try (it's actually already been published online but I won't be sharing the link to it with you until it's mostly finished). :P

Now, because I like my emulation to be as super accurate as possible I am very interested in purchasing a NES-101 console and a flash cart so that I can write my own ROMs to test anything that I either don't understand yet (like sound) or that is fairly obscure (like open bus behaviour). Once WedNESday has been finished, I'm gonna create my own emulation guide with all of the information I obtained from it and publish it on my site. My plan is to make WedNESday the 'byuu/Higan' of the NES scene. And when I'm done with it, I'll move onto all the other consoles such as the Game Boy/Super Nintendo/Playstation etc. :D

My plan is to get a NES-101 from ebay (the final hardware revision) followed by an EverDrive N8 Pro. So what kind of advice can you guys offer me? What kind of experiences have you guys had? Can anyone here hook me up with a little something? :beer:
User avatar
tokumaru
Posts: 12427
Joined: Sat Feb 12, 2005 9:43 pm
Location: Rio de Janeiro - Brazil

Re: Need advice buying a NES-101 and a flash cart

Post by tokumaru »

When it comes to buying hardware, where you are in the world can play a big part in it, since getting a specific version/revision might mean paying import taxes, inflated shipping fees, and stuff like that. If you're in Europe, right off the bat you're gonna have to choose between PAL or NTSC. If your focus is on emulation, you might actually want both.

I'm not sure what the current deal with the NES-101 is right now, but I assume they are pretty expensive these days. If you're open to it, a Famicom AV might be more affordable, since in Japan they don't usually jack up the prices for retro stuff as much as much as they do elsewhere. Advantages of the Famicom AV over the NES-101 include composite output (NES-101 only has RF) and the compatibility with carts using audio expansion, which might be relevant to you.

As for flash carts, the stuff Krikzz makes is excellent, and not unreasonably expensive (before you factor import taxes in!), and you can get an Everdrive N8 in both NES and Famicom formats.

I personally have been using a Famicom AV with a Famicom Everdrive N8 as my NES system of choice for a while. I occasionally use a NES-101 with an NES Powerpak, but the RF output is noticeably inferior. I really can't deal with the crappy cartridge connector of the original NES anymore, I own 2 or 3 of those which are working just fine, except for how hard it is to get the cartridge to actually connect.
Fiskbit
Posts: 890
Joined: Sat Nov 18, 2017 9:15 pm

Re: Need advice buying a NES-101 and a flash cart

Post by Fiskbit »

I, too, recommend an AV Famicom over an NES toploader; the Famicoms are cheaper and more functional, having composite output, expansion audio, and the Famicom expansion port. You can get an NES->Famicom adapter, though be warned that some of these have pin spacing problems, and many also don't connect NES EXP6 to the Famicom's audio in. EXP6 is used by modern carts for expansion audio. The adapter I got on eBay appears to be spaced just fine, but doesn't connect EXP6 and doesn't provide a great location to solder to.

The Everdrive N8 Pro is decent, but has limitations when it comes to hardware testing. You can't boot directly into a ROM at power-on, and the menu clobbers the state of registers and RAM (and doesn't even clean up after itself), so you'll never be able to test things like power-on state or CPU/APU power-on alignment. We recently discovered the Everdrive fakes open bus on addresses $4020+ by always returning the high byte of the address being accessed, which isn't always correct and breaks some tests. Anything relying on mapper behavior is basically no better than results you see in good emulators; it's only as accurate as the Everdrive's implementation. I've also encountered weird problems where the Everdrive thinks the button combination for its menu has been pressed during gameplay when it hasn't, and I've heard someone else report the same issue, but it's not a problem if you disable the 'in-game' menu. The N8 Pro is certainly convenient and is often plenty good to get the job done, but it doesn't eliminate the need for dedicated test cartridges in cases where accurate results are necessary.
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

First of all, a big thanks to the both of you for your fantastic responses.

Secondly, it would seem that something like the EverDrive might not be the best option for me. If I were to opt for a dedicated test cartridge, is that something that is already available to purchase somewhere online? If not, do you know of somebody who is capable of making such a thing?
User avatar
tokumaru
Posts: 12427
Joined: Sat Feb 12, 2005 9:43 pm
Location: Rio de Janeiro - Brazil

Re: Need advice buying a NES-101 and a flash cart

Post by tokumaru »

The problem with flash carts in general is that while the console is 100% authentic hardware, a flash cart never is. Like Fiskbit said, the menus will temper with the power on state and the mappers will be, at most, as accurate as the reverse engineering efforts made thus far permit. Flash carts are mostly made for players (which are way more numerous), not developers and researchers. If complete accuracy on the cartridge side is a must, I think we're still stuck with what we used to do 20+ years ago: installing sockets on original cartridges and programming EPROMs/FlashROMs...
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

That all makes perfect sense. All I would really need is the ability to load onto a cart a very simple NES program that allows me to manipulate RAM values to write 6502 code on the console itself and test it. I'm not really interested in things like built in mappers/menus etc.
calima
Posts: 1745
Joined: Tue Oct 06, 2015 10:16 am

Re: Need advice buying a NES-101 and a flash cart

Post by calima »

Retrostage has excellent no-solder solutions.
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

calima wrote: Mon Jan 03, 2022 1:52 am Retrostage has excellent no-solder solutions.
Could you please provide a link? I googled it but got some totally non-related results back.

Update: I just bought a Japanese NES (HVC-101) off of ebay. Delivery will take around 4 weeks. Gonna need the time to write the test ROM, get a power adapter, get an AV adapter and a flash cart.
calima
Posts: 1745
Joined: Tue Oct 06, 2015 10:16 am

Re: Need advice buying a NES-101 and a flash cart

Post by calima »

https://retrostage.net/?product_cat=nes

Seems they're on holiday til Jan 10. Use archive.org to see old versions of the discrete blaster, etc.
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

I understand that flash carts like the EverDrive influence open bus behaviour, but why is that exactly? Is it due to the OS being used or is it something hardware based? I would have thought that anything being read from one memory location to another wouldn't be subject to any changes by the cartridge itself.
User avatar
Ben Boldt
Posts: 1148
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: Need advice buying a NES-101 and a flash cart

Post by Ben Boldt »

My guess is that it is probably something to do with the active level shifters in the everdrive. Since the FPGA inside can only run on 3.3V logic (or maybe less), it has to use level shifters for each of the signals in the cartridge connector. These are effectively buffers. The direction of the buffer is either fixed input, fixed output, or controlled bidirectional, and this influences open bus.
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

tokumaru wrote: Sun Jan 02, 2022 4:38 pmIf complete accuracy on the cartridge side is a must, I think we're still stuck with what we used to do 20+ years ago: installing sockets on original cartridges and programming EPROMs/FlashROMs...
Did I understand that correctly? If I buy some flashing hardware, I can just flash an original cartridge? If so, that would be the perfect solution for me.
User avatar
gauauu
Posts: 779
Joined: Sat Jan 09, 2016 9:21 pm
Location: Central Illinois, USA
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by gauauu »

WedNESday wrote: Thu Jan 06, 2022 5:23 am
tokumaru wrote: Sun Jan 02, 2022 4:38 pmIf complete accuracy on the cartridge side is a must, I think we're still stuck with what we used to do 20+ years ago: installing sockets on original cartridges and programming EPROMs/FlashROMs...
Did I understand that correctly? If I buy some flashing hardware, I can just flash an original cartridge? If so, that would be the perfect solution for me.
No, he's suggesting you remove the ROM chips from the original cartridge, and then install new flashed/flashable chips (either EPROMS or Flash).

That said, there are places you can buy empty boards, or boards pre-populated with flashable chips, so I wouldn't stay we're stuck with that method of repurposing original cartridges. But a dedicated cartridge, using whatever mapper your game uses, is still the final gold standard that you'd want to test on.
WedNESday
Posts: 1284
Joined: Thu Sep 15, 2005 9:23 am
Location: Berlin, Germany
Contact:

Re: Need advice buying a NES-101 and a flash cart

Post by WedNESday »

Thank you, gauauu (how on earth do you even pronounce that name?). :D

So purchasing an NROM cart over the internet and then replacing the CHR and/or PRG ROM with something that can be flashed is what I am looking for. Correct?

While I'm not opposed to doing such a thing myself, I lack the ability and tools to do so. Does somebody offer such a service?
User avatar
Ben Boldt
Posts: 1148
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: Need advice buying a NES-101 and a flash cart

Post by Ben Boldt »

If you plan to do a lot of reflashing, I recommend wiring up something with ZIF sockets. This will make it easy to remove and replace the ROMs quickly and without damage. Especially since you are looking at NES-101 (top loading 72-pin NES), you can use all the room you need for these ZIFs without it needing to fit inside a cartridge shell.
Attachments
zif.jpg
Post Reply