EPROM file sources

GTZ

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I need to program an eprom for After Burner II. I don't think the mame files are the same as what I need. If I compare the checksum from my good eproms to the mame files there are a few that are the same but most are different. So no surprise that the newly programmed rom is not working right. I am a newbee to eprom programming and I wonder if this is my error or wrong source files. Is there different files for the conversion from After Burner to AB II. Any Help or file sources would be greatly appreciated.

I'm using mame file aburner2.zip
specifically eprom 1116
 
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I'm surprised I'm not seeing any other older version rom sets for this.

I'm going to guess no in the case of the conversion roms being different, cause I think they both ran the same exact hardware, it would've just been the same board with a romset for AB1 and another for AB2.

I don't know about your software, but on the one I use SuperproZ, I have to specify the rom type, and you load the MAME rom file in your buffer, and you just program it.

hopefully someone else can help you better. good luck
 
I'm using mame file aburner2.zip
specifically eprom 1116


AfterBurner uses NON-Jedec eproms (ie. Mask compatible 27c1000 or 27c301).

Number Pos Function Type

11116 93 objD-bit0 27c1000
11117 97 objD-bit1 27c1000
11118 101 objD-bit2 27c1000
11119 105 objD-bit3 27c1000


There are NOT the same as the standard 27c1001 or 27c010 eproms.

To read and/or program them, you need to select to correct eprom type.
( The following are all compatible mask-compatible eproms)

NEC 27c1000
Hitachi 27c301
Toshiba 57c1000

Good Luck,
Steph
www.Hobbyroms.com
 
What's the year of the file you are using? What's the checksum of the file you have? If I remember correctly, after a certain Mame version, they changed the way the files are kept. Compressed/Un-compressed, I don't remember.
 
I'm using MX 27c1000dc-12 is this eprom mask compatable?
The original chip was -20 is the faster chip an issue?
 
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I'm using MX 27c1000dc-12 is this eprom mask compatable?
The original chip was -20 is the faster chip an issue?

could be. I was told in one of my rom-related threads the speed can make a huge difference.

I had the exact same boardsets (Midway Y-units) and I had a board where all the roms would come up bad cause they were a different speed, even though they were both MKs.
 
I'm using MX 27c1000dc-12 is this eprom mask compatable?
The original chip was -20 is the faster chip an issue?

Two things....

For whatever reason, MX uses the number "27c1000"
for their JEDEC version. (ie. it is the same as a "normal" 27c1001 ).

This is hugely confusing, and had me guessing when I first used those chips.

So MX 27c1000 = "standard" 27c1001 = JEDEC

This is NOT the same as the NEC 27c1000,
which is a true mask-eprom.

So set your programmer to NEC 27c1000 or Hitachi 27c301.
Both of these WILL read correctly.
(...and probably program too... )

NB. Not all programmers support mask-roms,
so if you can't find the two types I listed above (...which are the most common),
your programmer can probably not support them.

--

As for speed, the SMALLER the number, the FASTER the eprom.
-12 means 120 nsec, -20 means 200 nsec

This is READ-ACCESS speed.
So the smaller the number, the FASTER the eprom reads the data
(ie. it is FASTER).

So -12 is FASTER than -20 ( ...I know, it's confusing ! )

For programming or using a programmer, speed makes no difference whatsoever.
( A programmer will read or program eproms of ANY speed ).

Where speed becomes an issues is on PCB where the clock cycle
is faster than the read-access of the eprom.

If you have a fast clock ( say 150 nsec pulse ),
-20 eproms won't work ( 200 nsec too slow for 150ns pulse ),
but a -12 eprom will work ( 120 nsec is fast enough to provide data within the clock pulse)

Truth be told I've rarely seen instances where an eprom was too slow,
but it can happen.

For any eproms over 1Mb (27c010 and up), you're "probably" OK with -20,
fine with -15, and laughing with -12.

Clear as mud ?

;-)

Steph
 
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Steph
Thanks for the info. I assumed the faster chips would be ok. Its too bad that MX had to add the confusion about their 27c1000. So with a little research i found a difference between the MX and NEC was that pin 2 and 24 were reversed. So with a butt ugly board hack I now have proper graphics. Thanks for all the help

Gregg
 
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