Search found 98 matches

by poorstudenthobbyist
Sat Aug 08, 2020 9:03 pm
Forum: SNESdev
Topic: Good free snes cart design
Replies: 4
Views: 364

Re: Good free snes cart design

I've got some reasonably priced boards :)
Prepopulated options too!!

Restocks and more options coming soon.

https://www.etsy.com/shop/PoorStudentHobbyist
by poorstudenthobbyist
Fri Jul 31, 2020 7:52 pm
Forum: SNESdev
Topic: I made a multi-function SNES PCB
Replies: 8
Views: 936

Re: I made a multi-function SNES PCB

Probably a few milliamps at most. That's not going to be your main concern.
by poorstudenthobbyist
Thu Jul 30, 2020 9:14 pm
Forum: SNESdev
Topic: I made a multi-function SNES PCB
Replies: 8
Views: 936

Re: I made a multi-function SNES PCB

Depends on the board, and I also tend to make the power traces a bit thicker than the others. But I normally just stick to something a bit bigger than whatever the manufacturer can guarantee. You don't want to hit their minimum. https://electronics.stackexchange.com/questions/5403/standard-pcb-trace...
by poorstudenthobbyist
Wed Jul 29, 2020 6:15 am
Forum: SNESdev
Topic: SNES SRAM Test ROM
Replies: 9
Views: 520

Re: SNES SRAM Test ROM

Yeah, I was trying to think of ways to test that out as well. I'm still thinking it through. In the meantime I can at least still test the CIC just fine with the programming board. It looks like you might be using multiplexers to switch between Hi and LoROM? Unless there are solder pads on the back....
by poorstudenthobbyist
Tue Jul 28, 2020 8:53 pm
Forum: SNESdev
Topic: SNES SRAM Test ROM
Replies: 9
Views: 520

Re: SNES SRAM Test ROM

Here's what I want to do with it: I offer PCBs with parts pre-mounted, and I recently found some surface mount SRAM to try out. My plan is to be able to produce carts with everything already on the board, except the EPROM. I designed a programming board with a SNES cart connector on it so I can plug...
by poorstudenthobbyist
Tue Jul 28, 2020 5:03 pm
Forum: SNESdev
Topic: SNES SRAM Test ROM
Replies: 9
Views: 520

SNES SRAM Test ROM

I've seen a bunch of miscellaneous test ROMs for SNES, but I haven't seen many that test for how much SRAM is on-board. And by extension, one should be able to tell what mode the cartridge is designed to use, as RAM locations are different between the two. Is there any kind of test ROM that does thi...
by poorstudenthobbyist
Fri Jul 24, 2020 9:42 am
Forum: Reproduction
Topic: Nothing left
Replies: 12
Views: 750

Re: FS: Hobby give up (electronic parts) & NES/FC Cart Reader

Really sorry to hear that Ice Man :(

I'm not in need of any parts (and I'm in the US anyway) but just wanted to say you've been a great help, to me personally, over the years (even if not through direct conversation). Hope you still pop in from time to time.
by poorstudenthobbyist
Wed Jul 22, 2020 6:02 am
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

The explainer references a normal SNES cart without 322s. If you read to the bottom, there's a section about bus conflicts that explains the 322 wiring.
by poorstudenthobbyist
Tue Jul 21, 2020 5:20 pm
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

HiROM games normally have /CART tied to /OE. Again, you can find all the answers in my explainer, I wrote it specifically for situations like this :) Ya know, it took me about five board revisions until I got it totally right ;) and even then I kept modifying the design. I think I'm on my fourteenth...
by poorstudenthobbyist
Sun Jul 19, 2020 9:30 am
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

It's all detailed on my explainer :) But if you use a '139 without SRAM, but still wire everything except SRAM /CE to the '139 it'll work. The "bridge both if no '139" connects the /CART signal to /OE on the EPROM (or multiplexers). But you don't need to (and shouldn't) do that if you have the '139 ...
by poorstudenthobbyist
Thu Jul 16, 2020 4:30 pm
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

The only game I really cared about was Pokemon Red, my first Pokemon game. Complete Pokedex with seven level 100 Pokemon. Not gonna throw away those hundreds of hours! I cut it close though, it took me 21 years to change the battery. I was surprised to find it in tact after not checking for about a ...
by poorstudenthobbyist
Thu Jul 16, 2020 4:18 pm
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

You could, but that requires a battery charge control circuit. More expensive and more complicated. Might as well use non-volatile RAM at that point. I'm also not aware of any rechargable coin cell batteries. They probably exist but I haven't looked. Besides, with the right SRAM, saves can last up t...
by poorstudenthobbyist
Thu Jul 16, 2020 3:07 pm
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

You also should check to see if the data retention or standby current is low as well. The lower it is, the longer your game will save. Generally -L or -LL parts have low currents for save retention. Coin cell batteries are rated for ~220mAh, so if you divide the amp-hour rating by the retention curr...
by poorstudenthobbyist
Thu Jul 16, 2020 12:48 pm
Forum: Reproduction
Topic: (SNES)Help With Circuit for LoRom M27C322
Replies: 72
Views: 13870

Re: (SNES)Help With Circuit for LoRom M27C322

I've used 1N914s without issue for a while, which are pretty similar to 1N4148s. The current required to supply the SRAM data retention isn't too high (assuming you pick the right SRAM) so your forward voltage will be low.

That said, schottky diodes are generally better.
by poorstudenthobbyist
Thu Jul 09, 2020 7:25 am
Forum: Reproduction
Topic: SRAM decoder 74LS139 for 27C160/27C322 LoRom/HiRom
Replies: 9
Views: 480

Re: SRAM decoder 74LS139 for 27C160/27C322 LoRom/HiRom

The way his multiplexers are wired is indeed what I was talking about.

It looks like his schematic is for LoROM only. I can't verify it'll all work but it looks ok at a quick glance. All the information for the connections are on the site I linked though.

(I spent a lot of time writing it :wink:)