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 Post subject: Newbie NES questions
PostPosted: Mon Sep 05, 2016 6:17 pm 
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Joined: Mon Sep 05, 2016 3:33 pm
Posts: 33
Im new to all this. Ive taken a few donor carts chips off. http://callanbrown.com has been very helpful. Doing research but kinda confused on a few things. First this is what I have in mind to buy so far. UV eraser as well.
27C2001 2Mbit EPROMs http://www.ebay.com/itm/10pcs-M27C2001-12F1-M27C2001-27C2001-2Mbit-EPROMs-/280767899506?hash=item415f122772:g:N~EAAOSw~gRVgSG1

TL866CS Programmer USB EPROM http://www.ebay.com/itm/High-Speed-TL86 ... SwzgRW1VEY

Trying to keep my budget as small as possible. I know I have to put some money into it but want to keep it low as I can if possible. Unfortunately donor carts seem cheaper for most repros than buying blank PCB boards, CIC chips, other chips needed and shells. From what Ive found anyways.

One of my main questions is about eproms. Cant decide what to get. Id like to get eproms that are most universal. Could I just use the 27C2001 2Mbit chips? I know they are 32 pin but if they were 28 couldnt I just not use last 4 pins?
Says here: http://callanbrown.com/index.php/advanced-mmc3-nes-reproduction
Quote:
In conclusion, get 27C020 or 27C2001 EPROMs if you can, to ensure compatibility with your intended game. All TL/TS/TKROM games use 128kB or 256kB (so 1Mbit or 2Mbit) ROMs. If you get 2MBit EPROMs, you can still use them with 1Mbit games. I'll explain how later.

That is where I got kinda confused and made me wonder if I could use 27C2001 to make about any cart?

What wire and solder would any of you recommend? I took apart a ethernet cat5e wire and it has thin wire that might be good to use for repros. I have 40/tin 60/lead 4oz, 113 g. solder. Think Ill need to go smaller.

Any info or suggestions on any of this would be great. Learning more and more everyday. Thanks so much!


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 Post subject: Re: Newbie NES questions
PostPosted: Mon Sep 05, 2016 8:42 pm 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 6032
Location: Seattle
dude3585 wrote:
27C2001 2Mbit EPROMs [at 85c/@10]
Trying to keep my budget as small as possible.
New SST39SF020 might be cheaper than UVEPROM+eraser. Maybe, maybe not.

Many EEPROMs can be programmed and erased off a single 5V supply; this isn't true of UVEPROMs. Building a single-voltage programmer is a straightforward task, but probably out of scope unless you either have a computer with a parallel port or can program a microcontroller.

Anyway, I personally find flash less frustrating, and by now it's every bit as durable of a technology.

Quote:
I know they are 32 pin but if they were 28 couldnt I just not use last 4 pins?
You can't get 28-pin programmable memories that hold more than 64 KiB / 512 kibit. This is enough for a many smaller games, but ... it's also not enough for many others.

You can look at NEScartDB's memory size statistics page.

When shoving a 1mbit new 'PROM into a 28-pin Mask ROM hole on a PCB, yes, those extra four pins will often hang over. Here's a recent thread with pictures of same.

Quote:
That is where I got kinda confused and made me wonder if I could use 27C2001 to make about any cart?
A X byte ROM can be programmed with any smaller number Y bytes. When Y is exactly half (or a quarter or an eighth &c) of X it's as though you just had a smaller ROM in the first place.

You should find "7. Optional: if your EPROMs are bigger than your ROMs," in Callan Brown's writeup.


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 Post subject: Re: Newbie NES questions
PostPosted: Mon Sep 05, 2016 10:45 pm 
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Joined: Mon Sep 05, 2016 3:33 pm
Posts: 33
Thanks! Starting to get it more. That thread for Holy Diver was kinda confusing though. The schematics. I havnt read too much on that yet.

I couldnt find any SST39SF020 cheaper than 27C2001 I posted. Any other suggestions are welcome. Maybe I should get a 10x 27C2001 32pin and 10x 28pin Eproms? Cost me about $20.
I dont mind getting a UV eprom eraser they seem cheap.

As of now I have a SLROM and a CHROM but the CHROM is junk now. I ruined a resister and many traces. I might rewire and get whatever resister it is down the road. Any idea what resister it would be? Not too worried. Far as I know CHROMs Ive seen are 32 KB each chip. Let me know if Im wrong.
I have this as a donor but says NES-SLROM-06. Not sure the 06 means out of curiosity.Probaly doesnt matter. http://bootgod.dyndns.org:7777/profile.php?id=368


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 Post subject: Re: Newbie NES questions
PostPosted: Tue Sep 06, 2016 12:30 am 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 6032
Location: Seattle
dude3585 wrote:
I couldnt find any SST39SF020 cheaper than 27C2001 I posted. Any other suggestions are welcome.
No, the new parts will definitely be more expensive than those used or new-old-stock UVEPROMs. I was just comparing to the additional cost of the UV eraser and shipping for it.

Quote:
Maybe I should get a 10x 27C2001 32pin and 10x 28pin Eproms? Cost me about $20.
I'd probably come up with a list of things you want to make first before you start...

Quote:
As of now I have a SLROM and a CHROM but the CHROM is junk now. I ruined a resister and many traces. I might rewire and get whatever resister it is down the road. Any idea what resister it would be? Not too worried. Far as I know CHROMs Ive seen are 32 KB each chip. Let me know if Im wrong.
CNROM...

Almost all are 32/32, yes, but there's a very small handful of other sizes. Joust is 16/16. Arkanoid is 32/16. this is 32/64, and this is 32/128.

Quote:
Not sure the 06 means out of curiosity.
PCB Version.


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 Post subject: Re: Newbie NES questions
PostPosted: Tue Sep 06, 2016 10:04 am 
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Joined: Mon Sep 05, 2016 3:33 pm
Posts: 33
Thanks!
Quote:
I'd probably come up with a list of things you want to make first before you start...

Ive got most bookmarked of what I need to order. What Eproms to get without wasting money is probably my biggest issue so far. Im ordering from China(please dont be crap chips) and takes a while to ship so dont want to get wrong chips on first order. Kinda why Id like to get more universal Eproms if I can. So far 27C2001 is all I need?


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 Post subject: Re: Newbie NES questions
PostPosted: Tue Sep 06, 2016 11:40 am 
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Joined: Sun Apr 13, 2008 11:12 am
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Location: Seattle
As long as you don't intend on making any of the small number of games with 512 KiB of PRG, yeah, you should be able to manage.


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 Post subject: Re: Newbie NES questions
PostPosted: Thu Sep 08, 2016 10:55 am 
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Joined: Mon Sep 05, 2016 3:33 pm
Posts: 33
Thanks for confirming that for me. Id hate to wait a month from China just to not be able to use them.

Bought a Mission: Impossible for $3 with messed up label. Took a part and it was a KONAMI-TLROM. From what Ive found they use there own PCB and chipset. Its a 28 pin without the 4 extra pin holes. Interesting. From what Ive googled I found http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=94947 so might be stuck with 128kb but thats fine. Little confused on the pinout so Ill probaly just save the board for when I get more experience. Also not what to do about "Mapper Ctrl" mirroring if anything. Seems to be a MMC4 so maybe I could still do a repro or homebrew and have to wire first 2 pins of each eprom or other way around. That is where I get confused with this Konami board. Looks like Nintendo let me create there own boards and chip legally of course compared to unlicensed games.
I should take baby steps and start with easier repros first. Hopefully down the road Ill be able to help others.


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 Post subject: Re: Newbie NES questions
PostPosted: Thu Sep 08, 2016 11:26 am 
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Joined: Sun Apr 13, 2008 11:12 am
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Location: Seattle
http://bootgod.dyndns.org:7777/profile.php?id=156

It's the same MMC3 as a Nintendo-manufactured PCB. The only tricky part to making a larger game is going to be the fiddly work soldering to the MMC3 itself.

http://wiki.nesdev.com/w/index.php/MMC3_pinout


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 Post subject: Re: Newbie NES questions
PostPosted: Tue Sep 20, 2016 4:51 pm 
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Joined: Sat Jul 04, 2015 9:58 am
Posts: 471
Location: -29.794229 -55.795374
Well, a practice that I think is good is to draw or write on a piece of paper what you intend to do.
Try to preview most steps you're going to do and draw in a way that you can just take a look and understand.
Here is my last project's draw as an example:
https://drive.google.com/open?id=0B0OtM ... VpDZXpsNGM

The final result (a little messy) is here:
viewtopic.php?p=179746#p179746
This also makes a good reference if later you want to make a similar project or even modify the old one in some way :-)

If you don't want to wait from China's post and have access to some old obsolete computer parts, most Pentium, Pentium II, K6 and earlier Athlon motherboards have 32 pin flash chips on it. Finding a suitable one is kind of a trial and error, but it's dirty cheap!

Although a standalone memory writer is the best, you can even the flash ROMs on the old motherboard (if it still boots).


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