Okay, I've been told that if I use EEPROM, I should use 28C64, just for a quick 16K prg and 8K chr demo, but I'm wondering if I should use EEPROM, and not Flashrom or EPROM. I've heard that Flashrom just has to be erased in blocks, and that was the only bad thing about them. I'm thinking I should use Flashrom, because it's cheaper. But which one should I use? and what should I program it with? And where should I aquire these items? thanks.
Firstly,
You can get cheap Flash/EPROM/EEPROM programmers here:
http://www.sivava.com/
or
http://www.willem.org/
If you're thinking about programming Genesis EPROMs, get the 16bit adapter for 27C160 and 27C322 whilst you're at it, you will save on shipping.
You can get cheap cheap 16 megabyte (27C160) and 32 megabyte (27C322) EPROMs from here: ($5 a piece! those things are like $30-$50 new)
http://stores.ebay.com/88-Electronics-Store
As for chips?
EPROMs costs the least, they are very cheap used, and all the used one's I've ever bought worked fine. I got all of mine surplus on Ebay or from various vendors. The only problem is, if you're doing testing, it can be cumbersome to erase and burn if you don't have a lot of chips (like less than 10 to work with). I usually have 10-20 on hand for debugging stuff, BURN, run code, thrown in eraser, grab another, rinse repeat.
Flash is the next cheapest, and is probably what you should use for debugging, if you don't want to cycle through EPROMs. The pinout can be different from EPROMs and EEPROMs. Its definalty not as common to get surplus or cheaply like EPROMs though. (you can usually get pulls from motherboards at the junkyard or computer waste places). And flash has to be erased in blocks.
EEPROM is the most expensive, but you can change one byte at a time (unlike flash). I'm not sure if EEPROM needs special voltages or not to reprogram???
Oh, and I haven't tried this method yet, but it might work... You could try soldering a CR2032 battery to some SRAM (which is getting cheaper these days). In which you could program it (without any special voltages), and use it. You could probably tie the write pin low or high (i forgot what makes it writeable), and use it like a EPROM, EEPROM, or FLash chip.
See this page:
http://nintendoallstars.w.interia.pl/romlab/msram.htm
Oh, I almost forgot to add, if you're going to use EPROMs, you'll need a UVC emitting light.
I've been able to make one for about $15.
You need a germicidal bulb (quartz). here:
http://www.topbulb.com/find/Product_Des ... ID_E_48194
And I bought the 4" fixture at Home Depot for $4.
I put it in a metal cracker tin, and used an old timer.
Okay, but I'm wondering something. Does the chip need to be the exact memory size? or can it be like 64k when you're writing 16k to it? I don't know, and I'd really like to. And I'm kind of confused about the whole adapter thing. Why do you need a special adapter for certain chips? I think that's stupid, and I don't know how you guys all figured this out. I think I'm going to find some reasonable Flashroms compatible with the willem whatever, and that will be good.
When using bigger memories than your board has room for, tie the highest order address pins to ground or +5V and you should be fine.
Sorry, I am a lame everyday newbie to this, but what flashroms should I use for a 16k prg and 8k chr game? If I use a SMB1 board, and just replace the chips, that won't be a problem, right? That game is really basic when it comes to chr/prg methods, right?
Well, you can just replace the chips when it comes to EPROMs. I don't know where to get any 28-pin DIP Flashroms. Digikey lists the AT29C256, but it seems to be out of stock everywhere.
Oh, well, I think I'm just going to use some EEPROMS. I found a 28C256 for $5.90! That's not expensive... and that's 32k, and that's fine with me, because I only have 16k of prg right now. and a 28C64 would be fine for chr data right? that's 8k, and my chr rom data is 8k. So do you think that would be fine?
Yeah, that should work. It might need to be rewired though, I'm not sure since I've never used EEPROMs.
The pinout of EEPROMs is different,
see the data sheet:
http://www.thought.net/jason/dev/rtvc/at28c256.pdf
Oh man... I looked at a willem programmer, and I have no idea what's going on. Okay, so how do you even like write the data to the chip? is there like a little slot you stick it in, and then just select the data with the software to write to the chip, and then it goes wala! it's written to the chip? Or is it really stupid and complicated? And, one last thing. Do the 28CXXX EEPROMS need an adapter? if so what one? I'm so confused, and I am very new to this, so sorry...
Okay, I think I might want EPROMs. If you buy 2 27Cxxx EPROMs, and you write 8K CHR data to one, and 16K PRG to the other, and you put them in a SMB1/Duck Hunt cart, there won't be any rewiring neccissary, will there? And why do you need a germicidal bulb for EPROMS?
Okay, I'm thinking about getting a willem programmer 4.0 already tested and built, do you think it will be worth the money? And do you think I should get it?
Well, it depends on what you'll use it for. If you want to use it for testing your own programs where you'll be making changes often, I think you'd be better served by a ROM emulator or something rewritable in-system like Squeedo. Having to swap chips constantly gets old really fast. It's much nicer to just have to hit a key on the PC and reset the NES. I spent $200 on the 512kB ROM emulator I have, which is a lot, but it was worth it for all the time I saved. A cheaper one I've found since then does up to 128kB for like $89 or so. Of course then you'll probably want to use CHR-RAM, unless you get a second ROM emu.
EPROMs need UV light to be erased, so I guess germicidal bulbs are a good source of that. You definitely don't want this stuff shining on your eyes and skin though, it needs to be enclosed in something. Plus you have to wait for them to erase. I'm not planning on getting an EPROM eraser myself, I'll just burn those when the code is totally finalized.
I don't think you'd need an adapter for EEPROMs. The adapters with the willem programmer (and other programmers) are usually so you can program chips that aren't DIP28/DIP32. Like PLCC and other surface-mount chips, basically chips that need a socket or other parts that aren't on the willem board.
Okay, I just understood drk421's idea about the old metal cracker tin with an old timer, thank you for explaining that. I heard on a site that you can erase EPROMs with sunlight, is that true? and I won't be constantly putting data on a real cartridge, only when it's absolutely necissary. I wouldn't be erasing/writing to it very often. Oh my god, desoldering is a pain in the ass. I desoldered the PRG and CHR chips in one of my SMB1/Duck hunt carts, and I almost destroyed the thing! I had to drip solder in some places where I scratched apart the circuits. Okay, but anyway, I'm thinking about getting a willem 4.0 already put together, and 2 EPROMs (27C64/27C256), and will I be fine with just getting those? Will I need any dumb adapters or anything? And just a question, you don't have to answer this, but I would appreciate it. Where on the willem programmer, do you put the chip that you're programming? I couldn't find it in the pic of the willem 4.0.
As far I heard, erasing EPROMS with sunlignt is possible, but slow and inacurate (the erasing won't happen proprely).
Disolvering can get crappy, it's sometimes better to add a small amount of solver before disolvering.
Normally, you should have a booklet with your programmer... just read it, hehe.
If you use a Mario/Duckhunt cart, 27C256 (CHR) and 27C512 (PRG) are the right size for it's bankswitching.
Oh, but doesn't 27C512 have 32 pins, and doesn't it need to be rewired? Oh, I then must read drk421's EPROM pinout tutorials on the main site. So I am just going to slap a quick 16k prg on the 27C512 and 8k chr on the 27C256, and I will be cool? And a willem 4.0 will be okay?
Oh, nevermind, the 27CXXX series doesn't need any modification, haha.
Okay, I am going to buy a willem 4.0 from
www.willem.org and it's all tested and put together and ready, and I'm going to buy a 27C256 and a 27C512 EPROM, will I be missing anything? or is a willem 4.0 okay? Please respond.
Sounds alright. If you want to run more than one set of ROMs on your cart you'll probably want a couple DIP28 sockets, and you'll probably need to take the NES apart so it'll fit also.
Okay, thanks. I'm currently having stupid trouble finding a willem 4.0 because I have a simon giftcard, and paypal sucks. By the way, are any of you going for the 2005 minigame compo? I didn't see any NES entries there, and it's set up all stupid, what's the deal?
be careful with those willem programmers..
a lot of them run on 5V USB only.. but programming many older 27C??? eproms requires a lot more power than that! Although it "might" work correctly it's outside manufacturer specs, and hence can't guarantee reliability and longevity!
Nothing beats a good programmer that can supply the real voltage via external AC or DC plug.
Yeah you'll definitely want a DC adapter to use with it. I know on the version I have at least, you can only use USB power with chips that only need 5V.
Just get a Willem with an external DC supply.
Okay, I bought an EPROM programmer that was pretty cheap, like 40 bucks, and well, it doesn't have the frickin' AC adapter! It uses USB supply. Well, The EPROMs I bought I think only need 4.5 to 5.5V, and we'll just hope for the best. If I'm completely doomed, don't even say anything, please, I'll cry...
Okay, I was wrong. The Amtel 27C256 requires 12.5v. Crap CRAP CRAP CRAP CRAP!!!!!!!!!! UGSDLGJSUTWOEIUT!!!!!!! I WAS SO EXCITED FOR MY FRICKIN THINGS TO COME AND NOW IT'S NOT GOING TO WORK!!!! AHHHH!!!!!!!! I AM ANGRY!!!!!! Maybe I can just solder a wire from a 6V battery to wherever the power supply is, hahaha. Hey, I wonder if that would work. Any suggestions that don't involve sending my programmer back and getting a new one?
Stuff like this almost never includes the DC adapter itself, but isn't there a plug for it on the board? Mine has a jumper to select between 'VDC' and 'VUSB'.
If you have a multimeter/voltmeter, you could also check the VPP pin and see if it gets close to 12.5V. They use a step-up regulator to increase the voltage on the board, I use my (universal) DC adapter set to 9V.
Or just get a pair of 6 volt lantern batteries, wire them in series, and use your voltmeter to see how close they come to 12 volts.
!! don't know how good idea this is ;D !!
or mabe use your computers psu. they output 12v.. just can't remember which color the cable has thought.. but that shouldn't be hard to find out with some googling
Hmm, I asked the guy I bought it from about it, and he said it should be fine, because it uses some method on the board that somehow gets enough voltage to the EPROM. He knew what he was talking about, so I'll trust him. I haven't gotten it yet. I'll just see what happens. But I'll come back if I have any questions. Yes, tepples, I was thinking about using 2 6V batteries to add up to 12 volts, but I just didn't know where I would put them, or where I would solder the wire. I'll see when it comes. I'm so excited though, I can't wait till my stuff comes! My EPROMs should come either today or tomorrow, beings as they came from digikey, which is in MN, which is where I live, and they shipped yesterday, so they should be coming, This sentence has too many commas, and stuff. My Willem PCB will be coming by the end of this week, I believe. Okay, with EPROMs, just so I know, they go in the cart with the writing right side up, right?
Okay, I got my EPROMs today. I was very excited, I opened them up. They were about half as big is the MaskROMs that were in there, I was mad! Okay, so is this normal? I have two Atmel EPROMs, one's an AT27C256 and the other is an AT27C512, and they are too small! I've always heard that people have to make more room for their EPROMs by removing the top bar, and removing some plastic in the cart cover, but this is definitely not the case for me! Did I get the wrong kind? What?
That's only if you install sockets for the ROMs, they'll sit higher and not fit in the cart case.
So is this normal? I'm just wondering, because they are very very small. Like here's how big the mask rom is
Code:
_______________
| |
| |
=================
here's how big my Eprom is
Code:
________
| |
|_______|
I'm not exaterating at all, those are the perportions. Why is this? Will it work? And the pins are different. They don't go lower than the chip's case, instead of being like this:
Code:
_____
|_____|
| |
| |
they are like this:
Code:
_____
_|____|_
And I'm really mad! Is this okay? Will I be able to use these?
WTF?
Dude, post some pictures.
Crap, sounds like you got surface-mount version (SOIC-28 probably). NES boards use DIP-28.
...CRAP!!!!! Okay, so I could get two new EPROMs, like this one:
EPROM
I know it's an OTP, but I don't really care, because they only cost like 1 dollar a piece. But I was just wondering if that's the kind I want, is it?
Yep, those ones will work.
Or you could get an adapter socket that fits in DIP-28 and takes SOIC-28 chips. Is that possible?
tepples wrote:
Or you could get an adapter socket that fits in DIP-28 and takes SOIC-28 chips. Is that possible?
Yeah, just on the expensive side for an OTP rom.
Okay, I just got my EPROMs today! I'm getting my Willem either on monday or tuesday. I'm just have a few questions, as usual. Okay, Here are two pictures of the chip on the board, and I'm wondering which one is right. Forgive me, I had to quick like edit the pictures in paint, becuase my digital camera has BAD quality:
http://www.freewebs.com/the_bott/Cart%20007.jpg
http://www.freewebs.com/the_bott/Cart%20008.jpg
Which one is the correct way? But I was just making sure, when I get my Willem, I can just split the PRG and CHR data with Copynes's software, and open the PRG data, and write that to the 27C512, and open the CHR data and write that to the 27C256, right? And since I kind of scratched apart some IO lines on the cart, I can just drip solder to connect them right?
Edit: Sorry, for some reason the urls take you right back to this topic page. Just copy/paste them into a new tab in firefox, or window in internet explorer or whatever you use.
Uh, I believe picture 8 is correct, face the notch wherever pin 1 (the square solder pad) is. That's a CNROM right? You can also go by the '161, all IC mounted horizontally will face the same direction.
The first pic (7) is right, I recognize it since I used an Atmel rom on the Garage Cart. Notice on the board, in gold it will show a little notch on one end of the chip. That's the side where pin #1 should be.
I'm using an NROM SMB1/Duck Hunt cart, and okay, where is pin 1? is it the one closer to the pins? That is very newbeish, but I think that's right, correct? and can I just split the data using the copynes software and write them to the chips? AND, I can just stick them straight to the cart, right? Please respond.
Pin 1 usually comes with two fashions on IC packages (view from top) :
Code:
+----------------+
| |
> |
| |
+----------------+
x
Pin 1 is there
+----------------+
| |
| |
|o |
+----------------+
x
Pin 1 is there
Then, the pin 2 is just on the right of pin1, etc... Until the end of the chip is there. Then, the pin n+1 is on the opposite side of pin n, but now you go from the right to the left, making the last pin just be on the opposite side of pin 1.
Oh, sorry, I meant on the cart. Sorry...
It's marked on the board, like I said. The outline of the chip is drawn on there (usually in white on a silk-screen layer, but on Nintendo boards it's just the gold). And there's the little notch drawn on one end, lines up with the chip. And often the pad for pin 1 will be square also, like kyuusaku said.
Oh, I am sad. So many things could be wrong! I programmed my chips today, and I made sure they were the right ones, and they were put in the right place the right way, and oh, I SPILLED SOLDER ON THE GOLD PINS ON THE CART! AND I CAN'T GET IT OFF! This is probably whats making my cart not do anything. Either that or sucky soldering job. Probably both. But I only spilled a little glob on the pins, but, I did smear it around a bunch. I don't think the pins are touching each other, but I do think that the dirt in the solder is bad! I am so mad, I was excited, and now I'm really bored, because I don't know what to do. Any suggestions? It just shows a blank screen when I put my cart in. I think that my chips are correct, because I did happen to turn it on, and then there was a whole bunch of crap on the screen. But I also think somethings not right, because nothing was working. What's wrong?
The problem is, it's not like a blob, it's like someone colored with silver marker on the cart! That's about how thin the layer is. By the way, do any of you have the problem where the solder sticks to the iron instead of just melting? And I need to desolder these chips, because they are soldered so poorly, it's not even funny. I like blobed solder on each one. I made sure the solder wasn't touching any I/O lines, though, because that would be very bad. I also made sure that the pins weren't connected in any way, like the solder from one pin wouldn't be touching the solder from the other. Just to make sure I did things right, you're supposed to just split the data with the copynes software, and write that data to the chips, right? I put it in the way you said, and it doesn't work. But, I'm going to try again, because I did a horrible job soldering. Just I have one question. When I put the chips in, and I start to solder, where should I touch the iron? like at the base of the pin? or what? I know how to solder, I'm just really really bad at it. And I was just wondering if there's a certain way I should do it.
You need to start with having the tip of the iron clean, and with a thin layer of (shiny) solder on it. I do that by melting some solder on it and wiping it on a wet sponge. That way it'll heat the joints faster and prevent the solder from sticking to the iron.
You should touch the iron to 2 things all at the same time. The base of the pin, the through-hole pad on the board. At the same time, touch the solder wire to the pad. The solder should very quickly flow into the hole and around the pin (don't use too much).
If it doesn't come out right the first time, and you need to heat it up again you may want to add a bit more solder also.
Be sure to wash your hands afterwards, be careful, etc.
Okay, what happens is when I put the solder to the tip, it just sits there, because the tip is not hot enough! When I move it up alittle, it melts, turns into a ball, and drips off right away! And I'm pretty sure my cart is done for. I completely wrecked the gold things, I'm pretty sure. I was trying to get the solder off of the thing, it's really scratched up, and I think I burned the plastic. I need a new cart! Does anyone know of any mapper 0 games where I can use the same size chips? And hopefully they're not glob tops... I would be interested to know of NROM games I could use for this, because I truly killed my smb1 cart...
It sounds like Celius has gotten a thin layer of solder on the card-edge "fingers" that come in contact with the NES 72-pin connector. I know of no way of completely removing solder once it's gotten on copper-clad (or whatever material they use that stays so shiny).
The best advice I have is to use something to file it down as much as possible. This will also remove the thin film of rosin that is sometimes left after soldering. Using a soldering iron will only make things worse with something like this. If you apply too much heat you might even lift the trace off the board.
One thing to check first is whether the pin mattered. In the past when PCs didn't have ZIF sockets for processors, people would sometimes bend/break a pin off the chip and later find that it wasn't important anyway.
Great point about washing your hands after you've been soldering. This is a step I never forget to take.
Thanks.
Yeah, I sanded most of the solder off, and it should be fine, when i get super glue. I need super glue to glue this one pin that is sticking up alittle. You know how the gold pins are supposed to be flat on the board? Yeah, one lost the glue, and needs to be glued back on before more damage is done! This is how it looks from the side:
Code:
______
____/_______
___________|
that thing sticking up is the gold pin that lost the glue, and it's getting damage too much, and I need to fix it.
I will do this tomorrow. I always wash my hands after dealing with solder. I hold my breath when I'm actually soldering. I don't want to inhale toxic fumes! But yes, blargg, I used fine sand paper, and most of it came off easily. But there is a dark area where the solder was, it's still a little silver looking, but It should be fine, I hope.
It'll still work if the solder is on the edge connector, who cares?
If it gets corroded, just re-tin it.
Oh my... I've really done it... I WRECKED IT! A FRICKIN GOLD PIN FELL OFF! IT FELL OFF! LIKE IT FELL OFF! THAT IS SO DUMB! MY SOLDERING IRON IS BROKEN! And I need a new cart so bad... And my stupid soldering iron is so dumb, like, I couldn't tin my iron, the solder would just ball up and fall off, so my tip of my soldering iron wouldn't work, and I couldn't even get solder to go into the pin holes. I need a new cart, there is no hope for this one. I had to solder a gold pin back together, and it is so scratched and ruined, I need a new mapper 0 cart. I wish I could search google for SMB1/Duck Hunt cart no glob tops. I can't because there are no NES game online stores that know what frickin' glob tops are, and they wouldn't know if it has maskroms, or glob tops. It is dumb, I want gamestop to sell NES games again! That was such a stupid move to take out old games at gamestop! I could go look there for an SMB1/Duck Hunt cart that had no gap, and I'd be good! But no, it has to be all dumb and complicated! I am mad! Any NROM games that could use a 27C256 and a 27C512? Because there is really no hope for this one.
tepples wrote:
When using bigger memories than your board has room for, tie the highest order address pins to ground or +5V and you should be fine.
Do you mean that when I use a 42 pins 27c322 on a 1J3M-20 pcb using a 36 pins MRom, I can ground the unused pins? Or do I need a multiplexer (74LS139 or 138) to combine the streams? I'd rather use 1 32Mbitter instead of 4 801's.