software error with address

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bod...@gmail.com

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Mar 27, 2016, 3:45:11 PM3/27/16
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hi my oscilloscope running 68k cpu has 4 lower + 4 upper eproms
right now when booting the scope halts with message ''software error 1111 address 0000ah0 , what address is this related? internal cpu address or rom address?

Michael Schwingen

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Mar 28, 2016, 11:59:11 AM3/28/16
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That does not sound like anything that is based on a 68k exception, so it is
probably some firmware-internal integrity check - in which case, you will
have to analyze that firmware to find out what the exact meaning is.

Assuming this is some kind of EPROM integrity check, you might try to read
all the EPROMs with reduced supply voltage (in an EPROM reader or rigged-up
device, eg. using an arduino) - sometimes, if the bits start to
deteriorate, you can still read the original values when lowering the supply
voltage. You could then re-program EPROMs with the corrected original
contents.

cu
Michael

Tom Evans

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Mar 29, 2016, 2:48:58 AM3/29/16
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On Monday, March 28, 2016 at 6:45:11 AM UTC+11, bod...@gmail.com wrote:
> hi my oscilloscope running 68k cpu has 4 lower + 4 upper eproms
> right now when booting the scope halts with message ''software error 1111 address 0000ah0 , what address is this related? internal cpu address or rom address?

That isn't "0000ah0", but from the PHOTO IN THE FOLLOWING it is "0000a0h", which makes a lot more sense.

http://www.eevblog.com/forum/repair/hp-54112d/

"Bod...", are you "Daxxin" or has someone else had the identical fault with a
HP 54110D oscilloscope, and make the identical typo?

0xA0 is in the vector area in one of the "TRAP #0 D 15 Instruction Vectors".

Are you sure it is a 68000? The big chip on the board doesn't have any recognisable part numbers to identify it as a 68000.

Tom

Michael Schwingen

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Mar 29, 2016, 5:18:48 AM3/29/16
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On 2016-03-29, Tom Evans <thomasalex...@gmail.com> wrote:
>
> Are you sure it is a 68000? The big chip on the board doesn't have any recognisable part numbers to identify it as a 68000.

The quoted service manual on that page seems to indicate is *is* an 68k -
the marking on the photo is a HP part number, and there are not many chips
in that kind of DIL package.

http://www.cpu-world.com/info/HP-parts.html

decodes that HP number to be a MC68000L.

cu
Michael

Tom Evans

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Mar 29, 2016, 9:12:03 PM3/29/16
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On Tuesday, March 29, 2016 at 8:18:48 PM UTC+11, Michael Schwingen wrote:
> http://www.cpu-world.com/info/HP-parts.html
>
> decodes that HP number to be a MC68000L.

Wow. So HP private label CPUs. Weird.

> software error 1111 address 0000a0h

No idea, but I can make some guesses. The 68k "trap" instruction causes one of 16 "software interrupts". The vector at 0x00A0 would be executed for a "TRAP #8", which has the opcode 0x4e48. That's only one bit different to an 'UNLK D0" instruction (unlikely, but possible). It is also close to one of the JSR instructions. So it could be "bit rot" in one of the EPROMs as previously suggested, causing execution of a TRAP instruction. It this is unused in that device then the vector might trigger an "unused interrupt" which could be printing that error.

If you can get another one of those oscilloscopes I'd try swapping the EPROMs as a set. Unless they've got identical code loaded into them you wouldn't be able to swap individual chips.

Tom

Michael Schwingen

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Mar 30, 2016, 11:35:30 AM3/30/16
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On 2016-03-30, Tom Evans <thomasalex...@gmail.com> wrote:
> On Tuesday, March 29, 2016 at 8:18:48 PM UTC+11, Michael Schwingen wrote:
>> http://www.cpu-world.com/info/HP-parts.html
>>
>> decodes that HP number to be a MC68000L.
>
> Wow. So HP private label CPUs. Weird.

Not only CPUs - look at the other ICs, they had private-labelled parts for
nearly everything for some time.

> No idea, but I can make some guesses. The 68k "trap" instruction causes
> one of 16 "software interrupts". The vector at 0x00A0 would be executed
> for a "TRAP #8", which has the opcode 0x4e48. That's only one bit
> different to an 'UNLK D0" instruction (unlikely, but possible). It is
> also close to one of the JSR instructions. So it could be "bit rot" in
> one of the EPROMs as previously suggested, causing execution of a TRAP
> instruction. It this is unused in that device then the vector might
> trigger an "unused interrupt" which could be printing that error.

Right. Checking EPROM contents would be my first attempt, too.

cu
Michael

bod...@gmail.com

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Apr 9, 2016, 5:26:40 AM4/9/16
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Thanks all for the help , yes its for sure an 68k cpu thats is custom label
net yet solved , what i did is downloaded a working back up of eproms and burned
it still boot with some steps now i get msg 02C39CH error and msg say ''to try reset the machine or contact HP'' the backup was a litle updated version than mine
because has eprom also on video card maybe incompatible?
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