Eproms for burning backup S+ chips

[slot monkey]

I want to backup some S+ chips.

From my research the game and reel chips can be a 27c512, is this correct?

Will 27C512-12FA eprom chips work for both game and reel chips in a S+?

I'm a newbie to the whole eprom and burning world.

Getting ready to purchase some blank chips and I want to make sure I get the right ones.

Thanks

[Buzz]

Well your half right, the SP go into a 27C512 but the SS needs a  27C64  This guy has the cheapest eproms I have found.   http://epromman.com/

Now this backup chip idea all sounds pretty good, that is until you all of a sudden figure out you have dozens of chip and can never find the one you need. Or worse yet it's corrupt.  I think most of us that have more than a few files, we just store them on our hard drive. Myself I use to keep a backup copy of the files on a thumb drive, after the thumb drive took a dump I started using a external hard drive. ( I also have them on a DVD )

Chip burning isn't all that difficult, I think if you had a stalk of bananas you could train a Chimpanzee to burn eproms.

[slot monkey]

Hey Buzz

You saved my bacon again!

Now this backup chip idea all sounds pretty good, that is until you all of a sudden figure out you have dozens of chip and can never find the one you need. Or worse yet it's corrupt.  I think most of us that have more than a few files, we just store them on our hard drive. Myself I use to keep a backup copy of the files on a thumb drive, after the thumb drive took a dump I started using a external hard drive. ( I also have them on a DVD )

I agree, just trying to get my ducks in a row for when I screw up a chip.

Chip burning isn't all that difficult, I think if you had a stalk of bananas you could train a Chimpanzee to burn eproms.

We will see if this monkey can learn a few things about burning eproms.

Thanks again!

[jay]

You can use a 27c512 for both.
You use an offset to burn the smaller chip
The 27c64 are cheaper but sometimes the per unit discoount makes buying all of 1 kind more advantageous.

An offset allows you write into different memory space in the bigger chip.
Computers read top down and burners write bottom up so you need to offset into the higher reaches of the chip..

[slot monkey]

@Jay

An offset allows you write into different memory space in the bigger chip.

Is the offset when you fill the bigger chip with the same info but multiple times?

thanks

[Buzz]

@Jay

An offset allows you write into different memory space in the bigger chip.

Is the offset when you fill the bigger chip with the same info but multiple times?

thanks

Yes Sir !!

[stayouttadabunker]

You can copy & paste the data the X amount of times needed to fill your chip but...
I always thought that an "offset" was to enter the data from a certain address line?

either way will work though

[jay]

Both work.
If your not comfortable with hex math then its pretty easy to screw up using an offset.
Loading a file 8x or doing a dos copy to make a longer file is easy.
Copy file1+file1+file1+file1 file2
This would take a 64k file and allow you to create a 255k file suitable for writing to a  27c256 chip.

[poppo]

Just to clarify, the 'dos' command that can be used in a batch file is:

copy /b 1.bin+1.bin+1.bin+1.bin+1.bin+1.bin+1.bin+1.bin 27512.bin /b

Where 1.bin is the original reel chip and 27512.bin is the resulting file. What I do is put a copy of the reel bin in the folder with the batch file and rename it 1.bin. Then I directly burn the 27512.bin I keep the original in it's original format. IMO it's just easier to deal with one chip type - 27C512

Note: you have to copy it 8 times for a 27C512 and 4 times for a 27C256

The offset method will work fine too if your burner software supports it.

[jay]

Wouldnt the 1 be %1  in a batch file.

[poppo]

Wouldnt the 1 be %1  in a batch file.

What I have posted above is exactly what I have in my batch file and have used a zillion times.    I named it 'slot reel join.bat', but it can be called anything. Note: the /b at the beginning and end is important as it tells the copy command that it's a binary file. It won't work properly without it. Works on all versions of windows up to an incuding Windows 7. But I use an XP machiine with my burner.

[knagl]

I always thought that an "offset" was to enter the data from a certain address line?

Correct.  An "offset" is ofsetting the starting point of the data on the chip.  The "fill method" described in this thread is a quick and dirty way to accomplish that, by simply copying the data over and over until it fills up the chip (and only a small portion of the chip that only contains only one copy of the data is actually used by the machine -- the rest of the data on the chip is ignored -- it could have valid data, all zeros, or corrupt data -- it doesn't matter, as the machine is only looking in one place on the chip for the valid data).

[stayouttadabunker]

I always thought that an "offset" was to enter the data from a certain address line?

Correct.  An "offset" is ofsetting the starting point of the data on the chip.  The "fill method" described in this thread is a quick and dirty way to accomplish that, by simply copying the data over and over until it fills up the chip (and only a small portion of the chip that only contains only one copy of the data is actually used by the machine -- the rest of the data on the chip is ignored -- it could have valid data, all zeros, or corrupt data -- it doesn't matter, as the machine is only looking in one place on the chip for the valid data).

Thanks knagl....that's what I thought...
I would be partly correct also in saying that:

"The checksum is the sum of the value of the needed file placed at the starting offset line address
but not the entire chip"?

Is there a better way to say this?  Damn I'm a nerd

[knagl]

I didn't consider the checksum in my post above.

The checksum of the entire chip would change based on what data (or lack thereof) is in the "unused/unneed" portion of the chip, however, I believe that the S+ looks for a security byte(s) that is part of the data in the one portion of data that is actually used and read by the machine (and to that end it doesn't matter what the checksum of the EPROM itself is).

[poppo]

Yes, the S+ actually will only see that one 'bank' of the larger chip, so it will only calculate the checksum on that. However (and this is a reason I keep the original 8KB file) is that you need to calculate the checksum just on that 8KB. So if someone has a 'multi-copy' eprom, then they need to take that into consideration when trying to verify a checksum. As noted abve the checksum on the whole chip would be wrong.