RE: Rom image file type question

Cameron,
 
When you look at the file that you saved to your disk, there's "size" and
"size on disk", assuming you're using some flavor of Windows. The "size" is
the size in bytes of the file, and "size on disk" is the amount of space
that this file was actually allocated on your disk. These can be two
different quantities based on the sector size, sectors per cluster, and size
of a cluster on your disk. For your purposes, you would want to make sure
that the "size" field accurately says 4096 bytes for a 4K ROM file. Ignore
what the "size on disk" field says.
 
That being said, it's unlikely that your disk is formatted in a way that
blows out a 4K file to 43K, so check again to see what it says. Could you
be saving it in the wrong format? Sure.. If you picked "S-Record" format
for example, that would use more bytes than the plain vanilla "binary"
format. If you were to open the file with a text editor, it should not be
human readable unless you speak binary. :-) If it reads as an ASCII text
file, it's the "wrong" format for the purpose of this exercise. They can
all be converted from one to another, so there's no really "wrong" format
though. It just depends what you are trying to work with.
 
If your verify fails, that indicates that you probably didn't fully erase
the EPROM. Or perhaps, you seated it incorrectly, or the EPROM is bad, or
you picked the wrong EPROM type. The type of the failure can give you some
clues. The programmer will tell you where the verify failed (usually). If
it fails at the first byte, you have a gross failure to program anything and
you'd go down one set of troubleshooting steps. If it fails somewhere
randomly in the "middle", you might have an erase problem. If it fails past
the end, you put the wrong device type in, because the size field was wrong.
You don't need to "write" zero's to initialize anything. That's what the
"erase" does for you. Make sure you leave the EPROM in the UV light long
enough for the device to properly erase. When these devices get old, they
start to fail. So, if you don't make it past this initial experiment,
consider getting a brand new EPROM to play with.
 
Joel-
 

-----Original Message-----
From: owner-vectorlist@vectorlist.org
[mailto:owner-vectorlist@vectorlist.org] On Behalf Of Cameron Rector
Sent: Saturday, September 16, 2006 9:52 PM
To: vectorlist@vectorlist.org
Subject: VECTOR: Rom image file type question

I thank everyone for all the help so far.............
I have set up my programmer and have it talking to the computer. I have
erased and programed a sample eprom and everything seams to work just fine.
Now, I am moving to the next step and I don't understand a couple of things.
 
1. When I upload the old eprom into ram and then copy ram to hard drive, my
file size is 43k or so. When I look at my new rom image it is only 4.096k. I
assume I am saving the information in the wrong format or something. Maybe
someone could help me understand what I am doing wrong.
 
2. I am going to research sumcheck, because I am not sure what I should or
shouldn't see for a sumcheck number.
 
3. After copying the eprom to ram my "verify" fails. is this because I need
to write "zeros" to ram before I download the eprom to ram?
 
I am sorry for the novice questions, I am reading every night and practicing
what I learn during the day, but I just need to learn more and more and
more......
 
Thanks for all the help so far and I really do appreciate it.
Cameron

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Received on Sat Sep 16 22:20:03 2006