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unixdude

Help dumping OS ROM

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Hi, all.

 

I know there are OS ROMs that I can download, but today what I'm trying to do is test the ROM chip that I actually have.  I received my TL866II+ EPROM burner today, but unfortunately my EPROM chips were misrouted and won't get here until at least tomorrow.  Anyway, I thought I'd try dumping the OS ROM chip, to see what I can see.  I'm on a Mac, and I have installed the minipro program and libusb.

 

Running "minipro -t" detects the TL866 and shows me the status of the pins, but I can't get it to read the chip.  I can't get it to tell me anything about the chip.

% minipro -t
Found TL866II+ 04.2.110 (0x26e)
[output snipped]
Hardware test completed successfully!
%

 

I tried running the following, but it does not result in a valid file:

minipro -y -p "[email protected]" -r OSROM.rom

I'm sure I'm just not telling it the correct device type, but I also can't get it to tell me what device it sees.

 

Any suggestions on how I can do this?

 

Thanks.

fr_1713_size1024.jpg

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The OS ROM should be read as a 27128 type (16KB) - I'm not familiar with the command line syntax, but I see you're trying 2764, which will result in only 8KB.

 

Edit: Maybe try "[email protected]" ?

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Thanks, I've tried several of the 27128 types, and each one results in an invalid file. Hmm...

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Do you get 16KB of $FF? or random data? or a 0byte file

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Are you sure that the chip in in the right part of the socket? Looks wrong to me...

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Orientation looks correct according to the key embossed on top of the case next to the socket.

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Yes, orientation is right, but the chip should be moved all the way to the right in the socket. At least, that's what my experience has been. Never used a burner like that, however...

 

RT*M

 

Bob

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Posted (edited)

bob is correct for the old burners, but this new burner wants it where it is as indicated by the arrow in the chip orientation embossed above the holder and in it's oddly worded info sheet.

Edited by _The Doctor__

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Yeah. Orientation is correct. Not sure about placement.  This is my first time using an EPROM burner and I’m just assuming that it should be able to read a ROM chip, but maybe it can’t. 
 

In any case, I get a file of 32768 identical characters, and they are the same character no matter where I place the chip. I don’t have a hex editor, but in vi they show up as an umlauted “y” letter. 
 

I think this chip is dead, and maybe it really is, and maybe it just won’t do anything anymore. See my recent comment in my other thread about help with my 600XL and 800XL for why I think the chip is dead. Maybe it’s just totally dead. 

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Posted (edited)

The pic shows the unit upside down but the top right shows the orientation guide on the white plastic which correlates with how it's inserted.

 

Are there any other parameters you can send, like e.g. the OS Rom needs the CS and OE pins active low.

Edited by Rybags

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Move the chip to the far right.

Pin 1 to the left, that is correct.

That is how I use my programmer.

Mine has this symbol:

+--+--+------------+

>  >  >                 |

+--+--+------------+

 

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Just wondering whether its easier to do this whilst the ROM is in the A8?

e.g. use the small basic program from this thread.

  • Like 1

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26 minutes ago, Wrathchild said:

Just wondering whether its easier to do this whilst the ROM is in the A8?

e.g. use the small basic program from this thread.

Cool. I didn’t know about that. But my suspicion here is that the chip is dead. I wanted to see if I could get anything out if it. I’ll have EPROM chips today and will burn a new one for my 600XL. 

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14 hours ago, Nezgar said:

Do you get 16KB of $FF? or random data? or a 0byte file

Yes, I do get 16KB of $FF.  Specifically, hexdump shows:

% hexdump OSROM.rom
0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
*
0004000
% ls -lh OSROM.rom 
-rw-rw-r--  1 unixdude  staff    16K Mar 26 21:12 OSROM.rom
% 

I was seeing 32768 bytes yesterday, but I've rebuilt the file.

 

Anyway, I think I'll chalk this up to "the chip is completely toast," as I suspected it was.  My EPROMs (TI TMS-27C128-1) are coming today, so I will burn an XL ROM image to one of them, then try booting my 600XL with that.  That will hopefully fix my 600XL.

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If the OS is dead then the Atari you insert it into wouldn't start up.  Likely you'd get a black or dark reddish brown screen every time.

(600XL and 800XL are the only unmodded machine types that use this chip)

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Just now, Rybags said:

If the OS is dead then the Atari you insert it into wouldn't start up.  Likely you'd get a black or dark reddish brown screen every time.

(600XL and 800XL are the only unmodded machine types that use this chip)

Yup, that's exactly what happens.  I detail the state of the 600XL and 800XL bootups using Sys-Check in this comment.  I just figured I'd try dumping the OS ROM, since that's all I can do with my new EPROM burner until I get the EPROM chips.

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16KB of $FF is the same result you'd get from the TL866 with NO EPROM inserted in the reader...

 

But yes, suggests a dead mask ROM ...

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Posted (edited)
On 3/27/2020 at 10:56 AM, mr-atari said:

Move the chip to the far right.

Pin 1 to the left, that is correct.

That is how I use my programmer.

Mine has this symbol:

+--+--+------------+

>  >  >                 |

+--+--+------------+

 

Tl866 on the foto is upside down you see how ic mark, pin 1 is near to the open

/close level. And when you used the software you see a picture how to insert the ic(eprom flash etc.).

I have all ready used on the megaspeedy flash. And update allso the xilinx chip(with the xilinx flasher) with the latest software version from 2017 where IS plate supported.

 

Gr. Marco

Edited by marcokitt2000

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I received my EPROM chips last Friday, and was able to burn an XL OS to the EPROM, and ... et voila ... my 600XL boots right up to the READY prompt. :)

 

Fun stuff.

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