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Old 25 July 2014, 09:15   #21
Toni Wilen
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Schematics do not fully match production version of CD32. AFAIK All CD32's have only single 16x512k ROM. (There is space for U6B, no socket installed)

My CD32 (2xRev3) has R597 connected, R596 is open. R598 and R599 do not exist.
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Old 25 July 2014, 16:14   #22
Telemachus
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Quote:
Originally Posted by Toni Wilen View Post
Schematics do not fully match production version of CD32. AFAIK All CD32's have only single 16x512k ROM. (There is space for U6B, no socket installed)

My CD32 (2xRev3) has R597 connected, R596 is open. R598 and R599 do not exist.
Have you been able to successfully disable the extended part of the rom? So far I've tried all suggestions to the best of my knowledge but nothing so far.
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Old 26 July 2014, 00:45   #23
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Tony's comment about the schematic not matching production CD32's got me wondering.
I pulled my CD32 out of storage, disassembled it and immediately saw R596/R597.

Ringing out these with my meter, I noticed 27 ohms of resistance from pin 1 of the ROM to one of the pads on R596... which coincided with microprocessor address line A1.

R597 was populated with a 27ohm resistor, but clearly microprocessor A1 was tied to pin 1 of the ROM... but no resistor in sight. So I pulled off the ROM, but no, no surface mount resistor under the ROM socket.

I then visually traced pin 1 of the socket through the board and discovered R598 and R599 on the back of the PCB (located underneath the Alice chip). R598 was installed, R599 is empty.

Since R597/R598 are shorted, ROM pin 1 (A18) is tied to microprocessor line A1.
Rom pin 42 (A19) is tied to processor line A21.

Pulling pin 42 out and tying it to +5V should do the trick.

Last edited by Shadowfire; 26 July 2014 at 00:58.
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Old 26 July 2014, 20:28   #24
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I'm sure I tried Pin 42 with +5 and it did not work, did you try it yourself when you opened your CD32?
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Old 26 July 2014, 22:18   #25
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No, I didn't try it.

That modification will make Kickstart ROM appear in both ROM locations.
If it doesn't work, then the system doesn't like having two copies of kickstart in the memory map. At this point there is no other "easy" way to remove the extended rom, other than burning a new one or adding additional logic.
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Old 11 April 2017, 06:43   #26
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An old thread, but full of strange information.

Pin 42 of the CD32 ROM is disconnected internally, so it doesn’t matter what you do with it.
You can program or read the entire ROM/EPROM without it even being connected to anything.

Pin 20 & 21 are bits of the data bus, not addressing.

Address bits are A0 - A18 (19 in total). The highest bit is A18 (pin 1).

Disconnecting A18 would disable half of the ROM,
but each CD32 image is interleaved and spread across the whole 1Mb.

So no, you’d have to write a new EPROM to do that.

Last edited by xArtx; 11 April 2017 at 07:21.
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Old 02 July 2017, 12:12   #27
8 Bit Dreams
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Hello,
don't want to create a new topic, just have CD32 Kickstart related question:
my original ROM is broken, and i like to burn one 27C800.
I have CD32 Kickstart rom and CD32 Extended rom, have byteswapped them, but i don't know, how should i burn them correctly?
The first part should be ROM and the extended part comes second, right?

Last edited by 8 Bit Dreams; 02 July 2017 at 15:04.
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Old 02 July 2017, 15:59   #28
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Nope.

http://eab.abime.net/showpost.php?p=922224&postcount=2
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Old 02 July 2017, 19:35   #29
8 Bit Dreams
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Quote:
Originally Posted by Jope View Post
Should Extended part come at 0X000000 and The KS 3.1 at =0x07FFF0?
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Old 02 July 2017, 20:16   #30
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So it seems + the word interleave that is specified in the post I linked to.

I don't think there is a ready made tool for creating this burnable image, you will need to code your own.
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Old 02 July 2017, 22:26   #31
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oh..
i just want to make my CD32 great (work) again..
can't belive, there is nowhere a ready image of the ROM in this world..
will just try out and let here know what results i have
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Old 20 July 2017, 12:23   #32
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there is some pseudo code and a real tool - REAL_CD32_CONVERTER.ZIP, but i cannot find it anywhere.
maybe someone can reupload the zip archive?
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