nesdev.org

I'd like to know what pinout should be adopted when designing new 72-pin boards (I'm trying to do some again for fun).

I personally don't care as all my NESes are either CIC-disabled or Famicom models, but if I'd ever want to distribute carts to other people that don't own a powerpak (be it for betatesting purposes, as a gift, or as a sale with or without profit) then some solution have to be found.

So far I was under impresison that RetroZone's CIClone was the major solution, but they're pretty much dead now so I don't know how to adapt the board design.

Or is it better to make famicom boards and ask people to use a FC->NES adapter ? But those aren't common anymore

krikzz's CIC implementation uses ATtiny13A and is open source: http://krikzz.com/pub/support/index.php ... evelopment

I'm not sure whether it's free to use, however, but I'd assume so...

Cool,

my guess is that I should adopt the following pinout ? Is this chip (ATiny13A) common and easy to program ?

I'm still not sure how "led" should be connected : Normally the chip should be trying to change regions, but only if the current region fails.

I think you just connect the pin labeled LED to anode and the cathode to ground.

SkinnyV wrote:I think you just connect the pin labeled LED to anode and the cathode to ground.

Yeah, and if you want the opposite indication (on during normal operation), you would connect the anode to 5V and the cathode to the LED pin.

But don't forget the current limiting resistor, else the diode will be emitting smoke instead of light.

Bregalad wrote:Or is it better to make famicom boards and ask people to use a FC->NES adapter ?

My opinion is this way is better (therefore, you only need one adapter with one CIC), except for PAL cartridges.

Of course you could produce and sell an adapter including CIC, for this purpose.

You can also provide ROM image files (possibly also for sale, if necessary) of the game, that customer can make their own cartridge (or load it into PowerPak or emulators); such thing can be done at a lower price than to sell the cartridge so it can be both options can be available to a customer; you should still sell a cartridge too, though.

zzo38 wrote:

Bregalad wrote:Or is it better to make famicom boards and ask people to use a FC->NES adapter ?

My opinion is this way is better (therefore, you only need one adapter with one CIC), except for PAL cartridges.

It's not better if you have a front-loader, which is most NES machines. You have to disassemble your NES to remove the cartridge tray if you want to try to stick a famicom cart and adapter in there. I think there do exist adapters with a ribbon cable or something else to deal with it, but these are rare/expensive. NES to Famicom adapters, on the other hand, are cheap and plentiful, but obviously they don't have a CIC issue.

Mmh, so is it more common to find new famicom-compatible cases or new NES compatible cases ? It seems both are rare, but at least for NES it's common to have bad sport games without having to costly import them from japan.

I thought the "bad sport games" phenomenon started in the fourth generation (Genesis and Super NES) when the leagues and players' associations started to warm up to licensing annual rosters for official video game adaptations. Prior to that, sport games like Blades of Steel and Tecmo Bowl had to stand on their own gameplay merits as opposed to relying on being published by the only publisher to have negotiated the license.

tepples wrote:I thought the "bad sport games" phenomenon started in the fourth generation (Genesis and Super NES) when the leagues and players' associations started to warm up to licensing annual rosters for official video game adaptations. Prior to that, sport games like Blades of Steel and Tecmo Bowl had to stand on their own gameplay merits as opposed to relying on being published by the only publisher to have negotiated the license.

Games like Major League Baseball, and NFL Football by LJN seem to fit that description well enough. They're licensed, considered bad, and extremely common (more so than even Blades of Steel). Plenty of other mediocre sports games are extremely common too, John Elway's Quarterback comes to mind.

So, it looks like RetroZone stopped to sell plain game cases anyways.

Does anyone knowns if there is a source of Famicom game cases other than famicom games ? Does the company that produces Everdrive cartridges makes a new mold, or does they use existing Famicom games ?
I think some day in the future it would be possible to 3d-print cases, but until then...

And, relating to PCB design, is it recommanded to connect "GND" components to only one, or to both GND pins of the cart edge ? It seems (I'm not too sure) Nintendo connects everything to both, but wouldn't that result in a nasty ground loop ?

Is it a catastrophe if there is not a bypass cap for every single chip ?

Bregalad wrote:Does the company that produces Everdrive cartridges makes a new mold, or does they use existing Famicom games ?

They're new shells, but AFAIK they all have the word "EVERDRIVE" and a hole on the side for the micro SD card.

Bregalad wrote:So, it looks like RetroZone stopped to sell plain game cases anyways.

Yeah once he caught wind that I was having a NES case mold made he stopped selling them and has been deferring people to me apparently.

I actually just got the first couple shots from the mold last week. There is still a little work left to buff/polish things up, but the first batch of cases is scheduled to be stamped out next week. Here's a pic of the first ones. Without the mold being buffed up, the ejector pins have to press extra hard to pop the case off the mold. So that's where the white marks are from, won't be an issue beyond these test shots.
https://dl.dropboxusercontent.com/u/183 ... shells.jpg

Let me know if you're interested in the dimensional specifics of them and I can get you some measurements. They're actually drafted from the 5-screw design as that made for a simpler mold design by leaving out the intricate tabs. I did adjust the backside labels to the next closest standard avery label size too. There was a slight mix up on the PCB dimensions, so they didn't come out to be an exact match of the original. They're pretty close though, and with a slight modification original boards can fit inside easily.

tokumaru wrote:

Bregalad wrote:Does the company that produces Everdrive cartridges makes a new mold, or does they use existing Famicom games ?

They're new shells, but AFAIK they all have the word "EVERDRIVE" and a hole on the side for the micro SD card.

I picked one up from Krikzz, I don't see much issue with the EVERDRIVE text or SD slot. One could easily put a label over the EVERDRIVE to mask it if desired, and I didnt even notice the SD card slot at first look. It's actually SD micro, so the hole isn't that big. IMO you can safely ignore the fact it's even there.

I can share pictures and some rough dimensions of his cases if you'd like. I measured everything up and have a draft of the max PCB dimensions with all the holes and everything. There's quite a few screw post/studs penetrating the board. Something like 5 IIRC, that make placement of a highly populated board a bit annoying. But still severely better than donors, and they have 3 screws instead of tabs only thankfully.

And, relating to PCB design, is it recommanded to connect "GND" components to only one, or to both GND pins of the cart edge ? It seems (I'm not too sure) Nintendo connects everything to both, but wouldn't that result in a nasty ground loop ?

I would say go ahead and connect both GND pins. I've never seen a board that didn't, and I'd be more concerned of potential issues from poor grounding than ground loops. Say for example your ONLY ground pin was dirty/damaged, you could fairly easily fry components on the board due to SCR latchup. Even if you have a good connector, hot swapping carts with only one ground pin leaves you much more suceptible to SCR latchup.

Is it a catastrophe if there is not a bypass cap for every single chip ?

Far from a catastrophe from what has been seen so far. Many retrozone releases don't have bypass caps at all. Most Nintendo boards only have 2 bypass caps even though they have 4+ chips on the board. My practice has been to have atleast one bypass cap for every two components. When to components are so close to eachother that you would end up putting two bypass caps right next to eachother it really doesn't make sense to have more than one bypass cap. The only other way around that I suppose is mounting bypass caps on the bottom of boards which is costly from an assembly standpoint.

Well, right now I'm just playing with PCB design, and I don't know if I'll ever do any significant production (very likely not, but who knowns).

The only reason I care about cases and CIC is because I'm forced to consider them when designing a PCB : You have to know the case because it changes the shape of the PCB, where holes have to be drilled and where it's forbidden to place components. As for the lockout chip, well that's kind of obvious, although I will likely never use them in my prototypes it's good to have room for one in a NES (non FC) cart.

I don't think the fact a word "everdrive" is printed is a problem (well it's publicity for them so that should give a discount on the cases prices ) and the small hole can easily be filled with some rubber tape or something.

I also throught 1 bypass cap for 2 chips should be fine, even if I was taught that normally you should have 1 per chip (or even more for large chips with multiple power pins).

I understand that ground loops is not always a problem (for digital electronics), but you say it's better than bad grounding, but isn't ground loop bad grounding ? Also, if it's possible to power the cart with a single VCC pin, it should be possible to power it with a single GND pin (or two half with two GND pins), because, well, the current is rigorously the same. I feel that Nintendo made the connector that way so that it doesn't damage anything when you insert a cartridge facing the wrong direction (which saved my life multiple times when I play with FC->NES or NES->FC adapters)

The extent to which a ground loop will be a problem is proportionate to the amount of current that's going through the loop (and, as a proxy, used anywhere on the board). For a small loop, on a board that's only going to ever be consuming ~60mA, you probably don't need to worry, since the B field will only be a few microtesla.

The ground fill on the NES mainboard has loops all over it, too.

The place ground loops really pose problems is if you have a possible reason for different "grounds" to not be the same (e.g. AV wiring with insufficiently isolated power supplies/I/O), or sources of B fields inducing current to flow through the loop.