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Old 21st Mar 2018, 11:46 pm   #1
Philips210
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Default Interpreting a hexdump table

Hi

For sometime now I've been wanting to do some experiments with EPROM ICs and in particular, there was a project in Elektor Electronics called Elabyrinth, a sort of electronic maze game. Having had next to no experience with EPROMs my difficulty is understanding the contents of a hexdump.

The relevant hexdump is shown in the attached pic. I am not asking for detailed information on the actual program rather the principles of how the data is entered to the programmer. I need to understand what the relevant fields mean in terms of address and data. In simple terms how would I interpret the entries in the table in order to program the EPROM?

I've not been able to find a good explanation of what each of the fields in the table mean and how to transfer this to the programmer.

Sorry for such basic questions but as you can tell I'm not experienced in this field. The EPROM is a 2716. I have a Stag PP28 EPROM programmer and a UV EPROM eraser as well. Any help would be much appreciated. Thanks.

Regards
Symon
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Old 22nd Mar 2018, 12:09 am   #2
McMurdo
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Default Re: Interpreting a hexdump table

they look like a simple memory dump to me. The first figure on the left is the address and the numbers that follow are the values in address (+0), address +1, address +2 etc to the end, and then onto the next new row which is another address followed by the bytes in consecutive addresses as before.

If you see what I mean.

Do you have the dump in a useable format or have you got to type in all those values by hand?

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Old 22nd Mar 2018, 12:23 am   #3
Philips210
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Default Re: Interpreting a hexdump table

Hi Kevin

Thanks for explaining that.
The only hexdump I have is the one in the previously attached pic, ideally a hexfile would make things easier so in it's absence, it seems the data has to be entered manually, a laborious task and probably prone to error.
I'll try to familiarise myself with the programmer to contemplate the program sequence.

Regards
Symon.
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Old 22nd Mar 2018, 12:27 am   #4
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Default Re: Interpreting a hexdump table

You need to find out what data format your programmer accepts. A typical one is described here: https://en.wikipedia.org/wiki/Intel_HEX

If that is what the programmer wants then you need a small program to convert it as working out the sumchecks is a bit tedious by hand.
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Old 22nd Mar 2018, 12:28 am   #5
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Default Re: Interpreting a hexdump table

You may be able to scan the printout and use OCR software to turn it into ASCII text. You would need to check carefully for OCR errors, but this would still be easier than typing it all in. You would then need to write a bit of code to turn the ASCII representation into binary data - easy enough to do if you have any experience with C or Pascal.
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Old 22nd Mar 2018, 12:38 am   #6
Philips210
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Default Re: Interpreting a hexdump table

Hi Paul.

I like the idea of using OCR but I wish that I had the programming skills to write suitable code to convert the ASCII code to binary. That's a useful project in its own right. For the time being, I would be more than happy to program the EPROM manually. I will now be familiarising myself with the Stag programmer.

Regards
Symon.
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Old 22nd Mar 2018, 12:43 am   #7
Philips210
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Default Re: Interpreting a hexdump table

Quote:
Originally Posted by GMB View Post
You need to find out what data format your programmer accepts. A typical one is described here: https://en.wikipedia.org/wiki/Intel_HEX

If that is what the programmer wants then you need a small program to convert it as working out the sumchecks is a bit tedious by hand.
Thanks for pointing out this GMB, I am learning more as I go along, it's more involved than I first thought but I will persevere with this.

Regards
Symon.
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Old 22nd Mar 2018, 12:46 am   #8
Dai Corner
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Default Re: Interpreting a hexdump table

There are online tools to convert ASCII to binary, such as https://onlinebinarytools.com/convert-ascii-to-binary

(Example, not endorsement ).
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Old 22nd Mar 2018, 1:25 am   #9
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Default Re: Interpreting a hexdump table

Quote:
Originally Posted by Philips210 View Post
Hi Paul.

I like the idea of using OCR but I wish that I had the programming skills to write suitable code to convert the ASCII code to binary. That's a useful project in its own right. For the time being, I would be more than happy to program the EPROM manually. I will now be familiarising myself with the Stag programmer.

Regards
Symon.
It's only a few lines of code, and you could write it in any old language you know or have available. An old DOS version of Turbo Pascal would be fine, and you'd have a bit of fun learning to use it - it's great for noddy programs like this, and the only reason I don't still use it is I don't have a conveniently bootable DOS system or emulator. You can download the old 5.5 version for free, and if you don't have a DOS version you could download and install FreeDOS.

If you can program an EEPROM then you can certainly handle the simple high level programming involved. There is plenty of example code around if you google.
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Old 22nd Mar 2018, 2:43 am   #10
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Default Re: Interpreting a hexdump table

if i had a better image i could type it all in and produce many different formats for you.
the 3 digit number before the colon (at the start of each row) is the high part of the address in the eprom, the numbers across the top i.e. 0,1,2,3,4,5,6,7,8 .etc are the low part of the address. to get the address in the eprom of a particular byte look at the number at the very top of the column and add it to the number at the very left of the row (windows calculator even has a mode for this under view->programmer, just be sure to select the Hex option).
however be aware that this hex dump is split into two columns of 16 bytes each
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Old 22nd Mar 2018, 6:06 am   #11
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Default Re: Interpreting a hexdump table

Quote:
Originally Posted by paulsherwin View Post
easy enough to do if you have any experience with C or Pascal.
Or even VB.
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Old 22nd Mar 2018, 7:44 am   #12
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Default Re: Interpreting a hexdump table

I remember typing such programs into a Sinclair MK14.... it was quite tedious but possible.
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Old 22nd Mar 2018, 11:06 am   #13
Philips210
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Default Re: Interpreting a hexdump table

Hi.

Please see attached part of the table. So taking the very first address, hex 0000, the 1 byte data assigned to that address is hex 1C, and in binary form would be 0001 1100.

Taking address 040E (binary 0000 0100 0000 1110) the data assigned to that address is hex 09 ( binary 0000 1001).

I am now understanding the format of the table and appreciate all your help so far thanks.

Regards
Symon.
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Old 22nd Mar 2018, 11:29 am   #14
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Default Re: Interpreting a hexdump table

Quote:
Please see attached part of the table. So taking the very first address, hex 0000, the 1 byte data assigned to that address is hex 1C, and in binary form would be 0001 1100.

Taking address 040E (binary 0000 0100 0000 1110) the data assigned to that address is hex 09 ( binary 0000 1001).
Almost, but not quite. Your hex 09 value (binary 0000 1001) will be at address hex 04E, not 040E. The first row of the table shows addresses 000...00F, the second shows addresses 010...01F, and so on.

This reminds me of hand typing hex code in to my ZX81 in my youth. It was a notoriously error-prone process!

Chris
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Old 22nd Mar 2018, 1:09 pm   #15
GeoffB17
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Default Re: Interpreting a hexdump table

Sorry to ask a silly question, but where did the hexdump come from?

Do you have a piece of software that generated it?

If so, can you not re-direct the output to a file?

You can then use a small prog (BASIC perfectly fine) to read the file and write the data out to make a raw binary image. Prog slightly more complicated if you need to manipulate the two column format shown in your example.

Much easier than entering everything by hand?

Geoff
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Old 22nd Mar 2018, 3:41 pm   #16
Philips210
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Default Re: Interpreting a hexdump table

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Originally Posted by cmjones01 View Post
Almost, but not quite. Your hex 09 value (binary 0000 1001) will be at address hex 04E, not 040E. The first row of the table shows addresses 000...00F, the second shows addresses 010...01F, and so on.Chris
Thanks Chris.

So taking one more example to clarify, hex address 02B has hex data 59 assigned to it or binary 0101 1001.

Regards
Symon.
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Old 22nd Mar 2018, 3:46 pm   #17
Philips210
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Default Re: Interpreting a hexdump table

Quote:
Originally Posted by GeoffB17 View Post
Sorry to ask a silly question, but where did the hexdump come from?
Geoff, the table is a print out from Elektor Electronics magazine March 1984.

Regards
Symon
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Old 22nd Mar 2018, 3:55 pm   #18
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Default Re: Interpreting a hexdump table

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Originally Posted by Philips210 View Post
So taking one more example to clarify, hex address 02B has hex data 59 assigned to it or binary 0101 1001.
Exactly.
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Old 22nd Mar 2018, 4:01 pm   #19
Philips210
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Default Re: Interpreting a hexdump table

Great, thanks. I am now on track and sorry to seem such a duffer at this, I should have taken more interest in this aspect of electronics in my younger years.

Regards
Symon
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Old 22nd Mar 2018, 4:11 pm   #20
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Default Re: Interpreting a hexdump table

Quote:
Originally Posted by Philips210 View Post
it seems the data has to be entered manually, a laborious task and probably prone to error.
If there's ever a next time try 'crowdsourcing' - get everyone here to type in 16 bytes of the code and send you their bit by PM. Be done in no time

Mole42 is right about the tedium of having to type code in as hex, the only way in which 'early' single board computers could usually be programmed.

Actually those were the deluxe versions, in around 1977/78 Elektor did a microprocessor teaching project (also based, like the MK14, on the INS8060 or SC/MP), which used LEDs and switches so all input and output was in binary.

As a matter of interest Symon, which microprocessor does this Elektor project of yours use?
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