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chatGPZ
Registered: Dec 2001
Posts: 11114 |
what is your RAM init pattern?
since i stumbled about yet another case of some ancient demo that relies on uninitialized RAM - and which would only work if you change the default VICE uses currently - i think its about time to collect some hard data about this phenomenon and perhaps at the end add proper configuration for it to VICE (or even choose a better default).
background: when you power on your C64, the RAM will not be zero, instead (about) half of the RAM cells will be 1, and the other half will be 0. this results in some kind of pattern (mostly) consisting of $00 and $ff. for example if you start VICE, then enter the monitor and look at a page of RAM it shows this:
(C:$e5d4) m c000 c0ff
>C:c000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c040 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c050 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c060 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c070 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c0a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c0b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>C:c0c0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c0d0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c0e0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
>C:c0f0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
this is the default pattern, which could be shortened to "64 times $00, 64 times $ff, repeat"
now i'd like to know how it looks like on your (real) C64... if you have some cartridge with ML monitor, all you need to do is power on your c64, check some memory page, and post the pattern here (you can ignore that some values wont actually be 0 or $ff - what matters is the general trend). additionally it would be extra cool if you could look into your C64 and post the type of RAM chips that it uses as well (since the pattern most likely depends on them) - they are labelled 4164 or 4464 or 41464 (please post everything written on it, the exact type and manufacturer is interesting here). Also please post the ASSY NO of the board, as the way RAM is wired up matters as well.
thanks for your help!
PS: if you are curious, Typical is the demo in question... if you can name other examples ("works in CCS64 but not in VICE is often an indicator for it), please post them too! |
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T.M.R
Account closed
Registered: Dec 2001
Posts: 749 |
<Post edited by moderator on 28/4-2016 11:03>
i'm getting something like this...
.:1000 04 14 00 b7 84 04 04 84
.:1008 04 f7 00 b3 a3 ef a3 b7
.:1010 04 f7 04 b3 24 ef 00 27
.:1018 04 b4 00 f3 04 04 00 a7
.:1020 04 10 00 b3 b4 00 00 fb
.:1028 00 b3 00 b3 a3 ff 00 fb
.:1030 04 f3 00 f3 04 ff 00 bb
.:1038 04 b7 00 f3 04 ff 00 b3
...on my workhorse breadbin from a cold start with an AR6 present. The board is an assy. 250425 (made in Hong Kong by Kalex) with most of the RAM saying MCM6665BP20 on the first line and FQQ8502 on the second.
My other breadbin is repeating ff ff 00 00 and seems to swap the values at the start of a page boundary - that's another assy. 250425, the RAM says JAPAN4L3U on the first line and HM4864P-3 on the second.
(i'm squinting a lot to read the numbers, there may be "hiccups" in there...)
i have another old board and i think two C64Cs knocking about that work, could pull them out at the weekend perhaps... |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
that first pattern seems... kinda unlikely :) for best results, use the c000 page (higher chance that it wasnt used for whatever) and power off the C64 for half a minute or so |
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T.M.R
Account closed
Registered: Dec 2001
Posts: 749 |
Quoting Groepazthat first pattern seems... kinda unlikely :) for best results, use the c000 page (higher chance that it wasnt used for whatever) and power off the C64 for half a minute or so
i've just started it again (with just an AR6 present, it's been off since i posted) and here's what i see:
.:c000 54 fb 00 ff 50 ff 00 ef
.:c008 04 ff 00 fb 27 af 90 af
.:c010 04 ff 00 fb 27 af 00 fb
.:c018 00 ff 10 fb a4 ff 00 ff
.:c020 54 fb 99 fb ff ff 99 ab
.:c028 00 fb 00 fb af af a2 af
.:c030 14 fb 04 fb 04 bb 00 bb
.:c038 10 1c 00 fb 86 af 24 ff
Then, after powering down for around two minutes, it looks like this:
.:c000 04 fb 00 ff 06 04 a0 fb
.:c008 04 ff 00 fb a6 ff b2 ff
.:c010 04 ff 00 fb 04 ff 02 fb
.:c018 04 ff 00 fb 04 ff 00 ff
.:c020 04 fb 00 fb 04 85 00 ff
.:c028 00 ff 00 fb ff ff 04 fb
.:c030 04 ff 00 fb 04 ff 00 bb
.:c038 04 fb 00 fb a3 df 54 34
Don't look at me, the odd number might be a typo because i'm tired but there's no simple $00 and $ff pattern! =-) |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
WEIRD =)
i have knocked up a very simple test program and added a bit of info here ... the program may be useful for those that dont have a ML monitor handy (do such people exist? =P) and the readme might give you a hint on what kind of description i am looking for. |
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Karmic
Registered: Apr 2015
Posts: 66 |
.:c000 03 f0 00 f0 00 f0 03 f0
.:c008 0f ff 0f ff 0f ff 0f ff
.:c010 81 ff ff ef ff 0f ff 0f
.:c018 f0 00 f0 00 f0 00 f0 00
.:c020 00 f0 00 f0 b0 f0 00 f0
.:c028 0f ff 0f ff 0f ff 0f ff
.:c030 ff c0 ff 0f ff ef 80 0f
.:c038 f0 00 f0 00 f0 00 f0 01
NEC D41464C 8605FU037, ASSY no. 250466 |
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iAN CooG
Registered: May 2002
Posts: 3132 |
this was also discussed in C64 Emulator Bugs
you can add to the problematic rels:
Comic Art 09
Flying Shark Preview + |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Isn't convenient to analyze the 00-3ff area? I think is the primary cause of programs malfunctions... |
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tlr
Registered: Sep 2003
Posts: 1714 |
Quote: Isn't convenient to analyze the 00-3ff area? I think is the primary cause of programs malfunctions...
Everything except the stack is initialized on reset...
I don't think it's especially common to rely on the initial contents of the $0100-$01ff area. |
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lft
Registered: Jul 2007
Posts: 369 |
Is this true for all the common carts too? |
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tlr
Registered: Sep 2003
Posts: 1714 |
Yes, most probably. In carts there are obviously some modifications to vectors and things like this though. |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
What make ram cells have the values they have after a cold start?
Is a "internal ram chip" question or some external factor can influence them?
Maybe bus 'activity' or other chips init?
Reading this Gpz sentence:
Quote:repeating ff,ff,00,00,00,00,ff,ff pattern, every $4000 bytes the pattern seems to be inverted (for another $4000 bytes). occasional random bytes
i started thinking if Vic init-activity can influence ram values...
FF/00 are values usually "leaved" on bus by vic during normal operations... |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
IAN: what an epic thread that is - we've come a long way since then :)
others: if you post dumps, try to post a page at least, that makes it much easier to see patterns. if you dont want to type it all out, you could also just save c000-d000 in monitor and send the resulting file to me via email. (in this case please put assy no and ram type in the filename AND add the same info in the mail itself) |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
Quote:What make ram cells have the values they have after a cold start?
Is a "internal ram chip" question or some external factor can influence them?
Maybe bus 'activity' or other chips init?
its simple law of physics - at poweron the internal flipflops will flip to either 0 or 1 randomly, roughly with a 50:50 chance. now the actual pattern you see results from the internal organisation of the RAM chips, for example neighboured cells may more likely flip into the same state. additionally *some* RAMs apparently contain reset circuitry that actually makes them start up in a defined way (i dont think this is a case for those old RAMs as found in C64s though).
other chips having an impact on the behaviour is unlikely IMHO - because for that to happen the write line of the RAM would have to be pulled low actively from somewhere, which shouldnt happen at poweron. |
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tlr
Registered: Sep 2003
Posts: 1714 |
It's DRAM we are talking about so the memory cells do not consist of flip-flops. They are basically caps.
I agree that the pattern probably arises from the organisation of the cells. Perhaps half of the cells are referenced to VDD? |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
ok perhaps i should have written "RAM cells" :) |
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tlr
Registered: Sep 2003
Posts: 1714 |
An important point about the cells being caps is that they aren't going to have 50:50 to land in any state. The most likely state is uncharged, which will mean 1 or 0 depending on if it is referenced to VDD or GND. Upon a power cycle all cells will (surprisingly slowly) fade towards the uncharged state. A quick power cycle will likely keep most contents.
The source of the spurious bits in the initial state could be due to how the refresh logic is implemented perhaps? E.g an initial glitch that injects some random bits. Remember that there are no resets to the ram chips so some strange startup behaviour is likely. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
sounds convincing :)
infact, now that i checked all my C64s (updates in the repo coming soon) i can say that even the one that first showed a seemingly random pattern (like TMR posted) dropped to mostly $00 and $ff after powering it off for several minutes. |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
...mmm...
What happen if you fill all ram with 00 or FF and power-cycle your C64?
If is only a question of caps charge,at least in one case,you should get the perfect 00/FF pattern back...
No? |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
i actually tried that on the C64 that retains its RAM content for very long... no, it doesnt improve the situation, you really have to power off for some (!) minutes (!).
i updated the test program and also the readme with results from my own C64s |
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tlr
Registered: Sep 2003
Posts: 1714 |
btw, I think the presence of randomness is an important emulation aspect. Some programs (originals) check for the presence of randomness in the start up pattern as a means of detecting a prefilled memory vs a normal "dirty" startup.
DarkStar BBS V3.1 did this, but I'm sure it was fairly common.
I guess it has to be pseudo random in some smart way, not to violate the reproducability of the startup sequence. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
good point! guess some code for that needs to be added to VICE as well then :)
edit: btw it would be cool to extract some of those "is there randomness in memory" check routines extracted and made into test programs :) |
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ChristopherJam
Registered: Aug 2004
Posts: 1378 |
C64C+RR
:b000 00 00 00 00 00 00 00 00
:b008 00 00 00 00 00 00 00 00
:b010 00 00 00 00 00 00 00 00
:b018 00 00 00 00 00 00 00 00
:b020 00 00 00 00 00 00 00 00
:b028 00 00 00 00 00 00 00 00
:b030 00 00 00 00 00 00 00 00
:b038 00 00 00 00 00 00 00 00
:b040 00 00 00 00 00 00 00 00
:b048 00 00 00 00 00 00 00 00
:b050 00 00 00 00 00 00 00 00
:b058 00 00 00 00 00 00 00 00
:b060 00 00 00 00 00 00 00 00
:b068 00 00 00 00 00 00 00 00
:b070 00 00 00 00 00 00 00 00
:b078 00 00 00 00 00 00 00 00
:b080 ff ff ff ff ff ff ff ff
:b088 ff ff ff ff ff ff ff ff
:b090 ff ff ff ff ff ff ff ff
:b098 ff ff ff ff ff ff ff ff
:b0a0 ff ff ff ff ff ff ff ff
:b0a8 ff ff ff ff ff ff ff ff
:b0b0 ff ff ff ff ff ff ff ff
:b0b8 ff ff ff ff ff ff ff ff
:b0c0 ff ff ff ff ff ff ff ff
:b0c8 ff ff ff ff ff ff ff ff
:b0d0 ff ff ff ff ff ff ff ff
:b0d8 ff ff ff ff ff ff ff ff
:b0e0 ff ff ff ff ff ff ff ff
:b0e8 ff ff ff ff ff ff ff ff
:b0f0 ff ff ff ff ff ff ff ff
:b0f8 ff ff ff ff ff ff ff f0
:c000 ff ff ff ff ff ff ff ff
:c008 ff ff ff ff ff ff ff ff
:c010 ff ff ff ff ff ff ff ff
:c018 ff ff ff ff ff ff ff ff
:c020 ff ff ff ff ff ff ff ff
:c028 ff ff ff ff ff ff ff ff
:c030 ff ff ff ff ff ff ff ff
:c038 ff ff ff ff ff ff ff ff
:c040 ff ff ff ff ff ff ff ff
:c048 ff ff ff ff ff ff ff ff
:c050 ff ff ff ff ff ff ff ff
:c058 ff ff ff ff ff ff ff ff
:c060 ff ff ff ff ff ff ff ff
:c068 ff ff ff ff ff ff ff ff
:c070 ff ff ff ff ff ff ff ff
:c078 ff ff ff ff ff ff ff ff
:c080 00 00 00 00 00 00 00 00
:c088 00 00 00 00 00 00 00 00
:c090 00 00 00 00 00 00 00 00
:c098 00 00 00 00 00 00 00 00
:c0a0 00 00 00 00 00 00 00 00
:c0a8 00 00 00 00 00 00 00 00
:c0b0 00 00 00 00 00 00 00 00
:c0b8 00 00 00 00 00 00 00 00
:c0c0 00 00 00 00 00 00 00 00
:c0c8 00 00 00 00 00 00 00 00
:c0d0 00 00 00 00 00 00 00 00
:c0d8 00 00 00 00 00 00 00 00
:c0e0 00 00 00 00 00 00 00 00
:c0e8 00 00 00 00 00 00 00 00
:c0f0 00 00 00 00 00 00 00 00
:c0f8 00 00 00 00 00 00 00 0f
Note the last byte of each page..
edit: I only powered off for a few seconds, but before that $c000-$c100 contained random crap from whatever I last ran a couple of weeks ago. |
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soci
Registered: Sep 2003
Posts: 473 |
Quoting Groepazi actually tried that on the C64 that retains its RAM content for very long...
I guess it was not a C64C then as that's where the 10 Ohm discharge resistor was added for the off position. |
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lft
Registered: Jul 2007
Posts: 369 |
Nah, that resistor drains a lot of caps, but not the ones inside the ram chips. Those are isolated from the outside world when they're not being addressed. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
soci: see the readme in the repo - it infact was a C64C :)
edit: ok so, updated the readme again with config examples for VICE that (mostly) reproduce the patterns listed. also i update the preview of the RAM init pattern in WinVICE r31093 (ie this nights build) so you can try yourself to reproduce the pattern of your C64 there.
Christopher Jam: does the pattern inverting happen every $1000 bytes over the whole memory range? (and could you check what RAM type is in your C64 please?)
where are the others? come one, we need more data! :) |
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Burglar
Registered: Dec 2004
Posts: 1031 |
here's mine, depends on time of day.
:c000 p0 0p p0 0p p0 0p p0 0p
:c008 p0 0p p0 0p p0 0p p0 0p
:c010 p0 0p p0 0p p0 0p p0 0p
:c018 p0 0p p0 0p p0 0p p0 0p
:c020 p0 0p p0 0p p0 0p p0 0p
:c028 p0 0p p0 0p p0 0p p0 0p
:c030 p0 0p p0 0p p0 0p p0 0p
:c038 p0 0p p0 0p p0 0p p0 0p
:c040 p0 0p p0 0p p0 0p p0 0p
:c048 p0 0p p0 0p p0 0p p0 0p
:c050 p0 0p p0 0p p0 0p p0 0p
:c058 p0 0p p0 0p p0 0p p0 0p
:c060 p0 0p p0 0p p0 0p p0 0p
:c068 p0 0p p0 0p p0 0p p0 0p
:c070 p0 0p p0 0p p0 0p p0 0p
:c078 p0 0p p0 0p p0 0p p0 0p |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
IIRC the C64 -emulated- in the C128 have a ram pattern of 64-$FF/64-$00 at start...
Maybe this was a cause of -incompatibility-, back in the days...
Anyway i started to collect datas from my machines.
I used a Breadbin, a C64c and a C64g.
I cold started all 3 c64 and i dumped all ram from $0800 to $CFFF, then i filled $0800-$CFFF with $FF and power-cycled each machine, waiting a minute before turn it on again.
Then re-dumped same ram area again. Same with $00.
All files, with some photos (expecially those of the Breadbin, which i photographed also ram chips) are in DB folder linked below.
Here is only "cold start" patterns:
C64 breadbin pattern looks like:
.:c000 36 ff 00 00 ff ff 00 00 6.......
.:c008 ff ff 00 00 ff ff 00 00 ........
.:c010 ff ff 00 00 ff ff 00 00 ........
.:c018 ff ff 00 00 ff ff 00 00 ........
.:c020 ff ff 00 00 ff ff 00 00 ........
.:c028 fe ff 00 00 ff ff 00 00 ........
.:c030 ff ff 00 00 ff ff 00 00 ........
.:c038 ff ff 00 00 ff ff 00 00 ........
.:c040 ff ff 00 00 ff ff 00 00 ........
.:c048 ff ff 00 00 fe ff 08 00 ........
.:c050 ff ff 00 00 ff ff 00 00 ........
.:c058 ff ff 00 00 bf ff 00 00 ........
.:c060 ff ff 00 00 ff ff 00 00 ........
.:c068 ff fb 00 00 ff ff 00 00 ........
.:c070 ff ff 00 00 ff ff 00 00 ........
.:c078 ff ff c0 40 fe fe cc 06 ...@..L.
.:c080 76 fe 00 00 ff ff 00 00 ........
.:c088 ff ff 00 00 ff ff 00 00 ........
.:c090 ff ff 00 00 ff ff 00 00 ........
.:c098 ff ff 00 00 ff ff 00 00 ........
.:c0a0 ff ff 00 00 ff ff 00 00 ........
.:c0a8 ff ff 00 00 ff ff 00 00 ........
.:c0b0 ff ff 00 00 ff ff 00 00 ........
.:c0b8 ff ff 00 00 ff ff 00 00 ........
.:c0c0 ff ff 00 00 ff ff 00 00 ........
C64C:
.:c000 ff ff ff ff ff ff ff ff ........
.:c008 ff ff ff ff ff ff ff ff ........
.:c010 ff ff ff ff ff ff ff ff ........
.:c018 ff ff ff ff ff ff ff ff ........
.:c020 ff ff ff ff ff ff ff ff ........
.:c028 ff ff ff ff ff ff ff ff ........
.:c030 ff ff ff ff ff ff ff ff ........
.:c038 ff ff ff ff ff ff ff ff ........
.:c040 ff ff ff ff ff ff ff ff ........
.:c048 ff ff ff ff ff ff ff ff ........
.:c050 ff ff ff ff ff ff ff ff ........
.:c058 ff ff ff ff ff ff ff ff ........
.:c060 ff ff ff ff ff ff ff ff ........
.:c068 ff ff ff ff ff ff ff ff ........
.:c070 ff ff ff ff ff ff ff ff ........
.:c078 ff ff ff ff ff ff ff ff ........
.:c080 00 00 00 00 00 00 00 00 ........
.:c088 00 00 00 00 00 00 00 00 ........
.:c090 00 00 00 00 00 00 00 00 ........
.:c098 00 00 00 00 00 00 00 00 ........
.:c0a0 00 00 00 00 00 00 00 00 ........
.:c0a8 00 00 00 00 00 00 00 00 ........
.:c0b0 00 00 00 00 00 00 00 00 ........
.:c0b8 00 00 00 00 00 00 00 00 ........
.:c0c0 00 00 00 00 00 00 00 00 ........
C64G
.:c000 00 00 ff ff ff ff 00 00 ........
.:c008 00 00 ff ff ff ff 00 00 ........
.:c010 00 00 ff ff ff ff 00 00 ........
.:c018 00 00 ff ff ff ff 00 00 ........
.:c020 00 00 ff ff ff ff 00 00 ........
.:c028 00 00 ff ff ff ff 00 00 ........
.:c030 00 00 ff ff ff ff 00 00 ........
.:c038 00 00 ff ff ff ff 00 00 ........
.:c040 00 00 ff ff ff ff 00 00 ........
.:c048 00 00 ff ff ff ff 00 00 ........
.:c050 00 00 ff ff ff ff 00 00 ........
.:c058 00 00 ff ff ff ff 00 00 ........
.:c060 00 00 ff ff ff ff 00 00 ........
.:c068 00 00 ff ff ff ff 00 00 ........
.:c070 00 00 ff ff ff ff 00 00 ........
.:c078 00 00 ff ff ff ff 00 00 ........
.:c080 00 00 ff ff ff ff 00 00 ........
.:c088 00 00 ff ff ff ff 00 00 ........
.:c090 00 00 ff ff ff ff 00 00 ........
.:c098 00 00 ff ff ff ff 00 00 ........
.:c0a0 00 00 ff ff ff ff 00 00 ........
.:c0a8 00 00 ff ff ff ff 00 00 ........
.:c0b0 00 00 ff ff ff ff 00 00 ........
.:c0b8 00 00 ff ff ff ff 00 00 ........
.:c0c0 00 00 ff ff ff ff 00 00 ........
Maybe C64G pattern is the best one =) ?
All files are here:
https://www.dropbox.com/sh/34w7h11mps6ss0n/AAB8t2CiRY9kT-5ADrXB.. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
could you post fotos from the RAM chips of the other two C64s as well? the case/keyboard is not very interesting for this =) |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Other 2 C64 were never opened, and i want to leave them as they are.
Someone else may have similar models and maybe wants to open them... |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
well, the model really doesnt tell you anything about the type of RAM (or even the ASSY) :) why not open them? afraid of voiding warranty? =D |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Matter of superstition ...
usually we say: "do not touch the sleeping dog", which means: "if something is working, don't thouch it".
I am sure that if I opened them, something stop working ...
=P
PS: I'm not superstitious because it brings bad luck.
=D
Edit: i'm pretty sure that more old are the ram chips, more random values are included in the patterns... |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
could you tell the ASSY NO of that breadbin then at least, please? :) |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Assy n. 250407 artwork 251137 rev C. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
updated
TMR/Karmic/Christopher Jam: could also make a memory dump? |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Just for the record, Typical works if in Vice we set "first byte: $00", "lenght of constant: 4" and "lenght of pattern: 8".
This create a pattern like:
.:c000 00 00 00 00 ff ff ff ff ........
.:c008 ff ff ff ff 00 00 00 00 ........
.:c010 00 00 00 00 ff ff ff ff ........
.:c018 ff ff ff ff 00 00 00 00 ........
.:c020 00 00 00 00 ff ff ff ff ........
.:c028 ff ff ff ff 00 00 00 00 ........
.:c030 00 00 00 00 ff ff ff ff ........
.:c038 ff ff ff ff 00 00 00 00 ........
.:c040 00 00 00 00 ff ff ff ff ........
.:c048 ff ff ff ff 00 00 00 00 ........
.:c050 00 00 00 00 ff ff ff ff ........
.:c058 ff ff ff ff 00 00 00 00 ........
.:c060 00 00 00 00 ff ff ff ff ........
.:c068 ff ff ff ff 00 00 00 00 ........
.:c070 00 00 00 00 ff ff ff ff ........
.:c078 ff ff ff ff 00 00 00 00 ........
.:c080 00 00 00 00 ff ff ff ff ........
.:c088 ff ff ff ff 00 00 00 00 ........
.:c090 00 00 00 00 ff ff ff ff ........
.:c098 ff ff ff ff 00 00 00 00 ........
.:c0a0 00 00 00 00 ff ff ff ff ........
.:c0a8 ff ff ff ff 00 00 00 00 ........
.:c0b0 00 00 00 00 ff ff ff ff ........
.:c0b8 ff ff ff ff 00 00 00 00 ........
.:c0c0 00 00 00 00 ff ff ff ff ........
|
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MagerValp
Registered: Dec 2001
Posts: 1055 |
https://www.dropbox.com/s/f7anwdudabcd9f4/Foto%202016-04-29%202..
https://www.dropbox.com/s/xzf5so80buvx62w/Foto%202016-04-29%202.. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
flavioweb: for typical the only thing that is needed is that $3fff is 0 (or perhaps even something different to $ff) :) |
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willymanilly
Registered: Jan 2016
Posts: 27 |
My C64C PAL (ASSY 250466) with Action Replay VI connected has the following power on ram values:-
0000-3fff 128 times $ff, 128 times $00, repeat
4000-7fff 128 times $00, 128 times $ff, repeat
8000-bfff 128 times $00, 128 times $ff, repeat
c000-ffff 128 times $ff, 128 times $00, repeat
There are some random bytes in the above patterns, mainly with the 4 LSB's of those bytes.
I got the same results without AR connected. |
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Pitcher
Registered: Aug 2006
Posts: 61 |
Cars in the garage tomorrow morning, I'll dig my 2 out and have a look, both breadbins but with completely different boards. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
willymanilly: could you check what type of RAM is on that board, please? |
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willymanilly
Registered: Jan 2016
Posts: 27 |
It has 2xMN41464-15 Japan 6D632 in U9 and U10 |
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willymanilly
Registered: Jan 2016
Posts: 27 |
I don't use dropbox so I just emailed pictures to you. You might want to check your spam if you don't receive them. |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
thanks!
so where are the rest? :) |
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Fierman
Registered: Feb 2002
Posts: 85 |
too lazy to dump and xfer file
http://i.imgur.com/Xlc9IBu.jpg
assy 250407
and here the internals:
http://i.imgur.com/9dOVV9O.jpg |
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Hypnosis
Registered: Mar 2015
Posts: 36 |
Mine looks like this:
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
0000 0000 0000 00ff ff00 0000 bf00 0000
0000 0000 0000 0000 0000 0000 4000 4000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
0000 0000 0000 00ff ff00 0000 bf00 0000
0000 0000 0000 0000 0000 0000 4000 4000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
0000 0000 0000 00ff ff00 0000 bf00 0000
0000 0000 0000 0000 0000 0000 4000 4000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ffff ffff ffff ffff ffff ffff ffff ffff
ASSY NO.250407
RAM M3764-20RS OKI Japan 3Y311 |
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Pitcher
Registered: Aug 2006
Posts: 61 |
Heres a sample, have photos if needed of full dumps, both from a cold start after being sat in the cuboard, last used 1 week+ ago.
Bread bin 1 - 1983 - assy 250407 - serial B1442003
has had some chips changed by the looks of things
C000 -
00 FF EE FF 00 00 00 EB
FF 00 FF 41 EE E2 FF 00
EE 00 FF FF FF 00 FF 00
EE 00 FF 00 FF 00 FF 00
00 FF FF FF EA A3 EF 40
EB EF FF 21 00 C0 FF E3
EF 00 FF A0 FF 00 FF 00
Bread bin 2 - 1984 - assy 250425 - serial B2399395
c000 -
FF 00 FF 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00
FF 00 FF 00 77 00 FF 00
FF 88 75 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00
FF 00 DF 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00 |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
could you also check the type of RAM chips please? |
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Pitcher
Registered: Aug 2006
Posts: 61 |
Quote: Heres a sample, have photos if needed of full dumps, both from a cold start after being sat in the cuboard, last used 1 week+ ago.
Bread bin 1 - 1983 - assy 250407 - serial B1442003
has had some chips changed by the looks of things
C000 -
00 FF EE FF 00 00 00 EB
FF 00 FF 41 EE E2 FF 00
EE 00 FF FF FF 00 FF 00
EE 00 FF 00 FF 00 FF 00
00 FF FF FF EA A3 EF 40
EB EF FF 21 00 C0 FF E3
EF 00 FF A0 FF 00 FF 00
Bread bin 2 - 1984 - assy 250425 - serial B2399395
c000 -
FF 00 FF 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00
FF 00 FF 00 77 00 FF 00
FF 88 75 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00
FF 00 DF 00 FF 00 FF 00
FF 00 FF 00 FF 00 FF 00
Breadbin 1 - mn4164p
3n6-15
Breadbin 2 - mn4164p
4d1-15 |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Coding my own emu (don't ask why) and I just noticed that the KERNEL relies on uninitiated memory. Check this small startup dump of the KERNEL:
FCE2 A2 LDX #$FF A:00 X:00 Y:00 P:24 SP:FD
FCE4 78 SEI A:00 X:FF Y:00 P:A4 SP:FD
FCE5 9A TXS A:00 X:FF Y:00 P:A4 SP:FD
FCE6 D8 CLD A:00 X:FF Y:00 P:A4 SP:FF
FCE7 20 JSR $FD02 A:00 X:FF Y:00 P:A4 SP:FF
FD02 A2 LDX #$05 A:00 X:FF Y:00 P:A4 SP:FD
FD04 BD LDA $FD0F,X A:00 X:05 Y:00 P:24 SP:FD
FD07 DD CMP $8003,X A:30 X:05 Y:00 P:24 SP:FD
FD0A D0 BNE $FD0F A:30 X:05 Y:00 P:24 SP:FD
FD0F 60 RTS A:30 X:05 Y:00 P:24 SP:FD
FCEA D0 BNE $FCEF A:30 X:05 Y:00 P:24 SP:FF
FCEF 8E STX $D016 A:30 X:05 Y:00 P:24 SP:FF
FCF2 20 JSR $FDA3 A:30 X:05 Y:00 P:24 SP:FF
FDA3 A9 LDA #$7F A:30 X:05 Y:00 P:24 SP:FD
FDA5 8D STA $DC0D A:7F X:05 Y:00 P:24 SP:FD
FDA8 8D STA $DD0D A:7F X:05 Y:00 P:24 SP:FD
FDAB 8D STA $DC00 A:7F X:05 Y:00 P:24 SP:FD
FDAE A9 LDA #$08 A:7F X:05 Y:00 P:24 SP:FD
FDB0 8D STA $DC0E A:08 X:05 Y:00 P:24 SP:FD
FDB3 8D STA $DD0E A:08 X:05 Y:00 P:24 SP:FD
FDB6 8D STA $DC0F A:08 X:05 Y:00 P:24 SP:FD
FDB9 8D STA $DD0F A:08 X:05 Y:00 P:24 SP:FD
FDBC A2 LDX #$00 A:08 X:05 Y:00 P:24 SP:FD
FDBE 8E STX $DC03 A:08 X:00 Y:00 P:26 SP:FD
FDC1 8E STX $DD03 A:08 X:00 Y:00 P:26 SP:FD
FDC4 8E STX $D418 A:08 X:00 Y:00 P:26 SP:FD
FDC7 CA DEX A:08 X:00 Y:00 P:26 SP:FD
FDC8 8E STX $DC02 A:08 X:FF Y:00 P:A4 SP:FD
FDCB A9 LDA #$07 A:08 X:FF Y:00 P:A4 SP:FD
FDCD 8D STA $DD00 A:07 X:FF Y:00 P:24 SP:FD
FDD0 A9 LDA #$3F A:07 X:FF Y:00 P:24 SP:FD
FDD2 8D STA $DD02 A:3F X:FF Y:00 P:24 SP:FD
FDD5 A9 LDA #$E7 A:3F X:FF Y:00 P:24 SP:FD
FDD7 85 STA $01 A:E7 X:FF Y:00 P:A4 SP:FD
FDD9 A9 LDA #$2F A:E7 X:FF Y:00 P:A4 SP:FD
FDDB 85 STA $00 A:2F X:FF Y:00 P:24 SP:FD
FDDD AD LDA $02A6 A:2F X:FF Y:00 P:24 SP:FD
FDE0 F0 BEQ $FDEC A:FF X:FF Y:00 P:A4 SP:FD
Right there at $FDDD!!! What the fuck? :)
Kind regards, Andreas |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Code at $FDDD is executed twice during reset:
$FF5B/65371: Initialize screen editor
Jump from $FCFB, $FF81:
FF5B: 20 18 E5 JSR $E518 ; Initialize I/O
Jump from $FF61:
FF5E: AD 12 D0 LDA $D012 ; VIC: Raster Position
FF61: D0 FB BNE $FF5E
FF63: AD 19 D0 LDA $D019 ; VIC: Interrupt Request Register (IRR)
FF66: 29 01 AND #$01
FF68: 8D A6 02 STA $02A6 ; Flag: TV Standard
FF6B: 4C DD FD JMP $FDDD ; Enable Timer
first "setup" is overwritten by the second call at $FDDD |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
yes, ok, still bad design. More over, when autostarting files the timing between c64 / vic may vary depending on men init. Can be good to know. :) |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
please.... keep that thread free from offtopic (make a new thread, its interesting afterall :)) - but post your own RAM init pattern! we really need more data! |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: please.... keep that thread free from offtopic (make a new thread, its interesting afterall :)) - but post your own RAM init pattern! we really need more data!
Sorry! :) |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
I have a ram dump from a breadbin with ceramic ram chips:
https://dl.dropboxusercontent.com/u/93655104/CeramicRAM.zip
At powerup
0000:0000 | 00 00 00 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E | ...~ÿÿ~~ÿÿ~~ÿÿ~~
0000:0010 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E FF | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~ÿ
0000:0020 | 83 81 00 71 00 81 00 00 81 81 00 00 81 81 00 71 | ...q...........q
0000:0030 | 83 81 00 00 89 81 00 00 81 81 00 00 81 81 00 0A | ................
0000:0040 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~~
0000:0050 | FF FF 7E 7F FF FF 7F 7E FF FF 7E 7E FF FF 7E 7E | ÿÿ~.ÿÿ.~ÿÿ~~ÿÿ~~
0000:0060 | 81 81 00 00 81 81 00 00 81 81 00 60 81 83 00 00 | ...........`....
0000:0070 | 71 83 00 00 81 81 00 04 81 81 00 00 83 40 75 00 | q............@u.
0000:0080 | DF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E | ßÿ~~ÿÿ~~ÿÿ~~ÿÿ~~
0000:0090 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E FF | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~ÿ
0000:00A0 | 8F 81 00 71 81 81 00 00 81 81 00 00 81 81 00 71 | ...q...........q
0000:00B0 | 8B 81 00 00 89 81 00 00 81 81 00 00 81 81 00 0A | ................
0000:00C0 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~~
0000:00D0 | FF FF 7E 7F FF FF 7B 7E FF FF 7E 7E FF FF 7E 7E | ÿÿ~.ÿÿ{~ÿÿ~~ÿÿ~~
0000:00E0 | 81 81 00 00 81 81 00 00 81 81 00 74 81 83 00 00 | ...........t....
0000:00F0 | 51 83 00 00 81 81 00 04 81 81 00 00 81 01 75 00 | Q.............u.
0000:0100 | 76 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF | v~ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ
0000:0110 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF 7E | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿ~
0000:0120 | 06 00 81 F0 81 00 81 81 00 00 81 81 00 00 81 F0 | ...ð...........ð
0000:0130 | 02 00 81 81 08 00 81 81 00 00 81 81 00 00 81 8B | ................
0000:0140 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ
0000:0150 | 7E 7E FF FE 7E 7E FE FF 7E 7E FF FF 7E 7E FF FF | ~~ÿþ~~þÿ~~ÿÿ~~ÿÿ
0000:0160 | 00 00 81 81 00 00 81 81 00 00 81 F1 00 02 81 81 | ...........ñ....
0000:0170 | F0 02 81 81 00 00 81 85 00 00 81 81 02 C1 F4 81 | ð............Áô.
0000:0180 | 5A 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF | Z~ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ
0000:0190 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF 7E | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿ~
0000:01A0 | 0A 00 81 50 00 00 81 81 00 00 81 81 00 00 81 50 | ...P...........P
0000:01B0 | 0A 00 81 81 08 00 81 81 00 00 81 81 00 00 81 8B | ................
0000:01C0 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ
0000:01D0 | 7E 7E FF 7E 7E 7E DA FF 7E 7E FF FF 7E 7E FF FF | ~~ÿ~~~Úÿ~~ÿÿ~~ÿÿ
0000:01E0 | 00 00 81 81 00 00 81 81 00 00 81 F1 00 02 81 81 | ...........ñ....
0000:01F0 | 50 02 81 81 00 00 81 85 00 00 81 81 00 C0 F4 81 | P............Àô.
Filling ram with $FF then turned off and on after 30 secs:
0000:0000 | 00 00 00 8A FF FF 7E 7E FF FF 7E 7E 8B FF 7E 7E | ....ÿÿ~~ÿÿ~~.ÿ~~
0000:0010 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 8A | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~.
0000:0020 | 81 80 0C 00 81 81 00 00 E1 81 C0 00 81 81 00 00 | ........á.À.....
0000:0030 | 81 81 00 54 81 81 00 00 81 81 00 00 41 81 00 00 | ...T........A...
0000:0040 | FF FF 7E FF FF FF 7E 7E FF 9F 7E FF FF FF 7E 7E | ÿÿ~ÿÿÿ~~ÿ.~ÿÿÿ~~
0000:0050 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E EE FF 7E 7E | ÿÿ~~ÿÿ~~ÿÿ~~îÿ~~
0000:0060 | 81 81 00 80 81 81 00 00 81 81 00 00 81 81 80 74 | ...............t
0000:0070 | 81 81 00 00 81 81 00 00 81 81 00 06 83 81 00 00 | ................
0000:0080 | FF FF 3E 8F FF FF 7E 7E FF FF 7E 7E 8F FF 7E 7E | ÿÿ>.ÿÿ~~ÿÿ~~.ÿ~~
0000:0090 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 0B | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~.
0000:00A0 | 81 81 0C 00 81 81 00 00 F5 81 A0 00 81 81 00 00 | ........õ. .....
0000:00B0 | 81 81 02 54 81 81 00 00 81 81 00 00 01 81 00 00 | ...T............
0000:00C0 | FF FF 7E FE FF FF 7E 7E FF 9F 7E FE FF FF 7E 7E | ÿÿ~þÿÿ~~ÿ.~þÿÿ~~
0000:00D0 | FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E | ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ~~
0000:00E0 | 81 81 00 00 81 81 00 00 81 81 00 00 81 81 80 74 | ...............t
0000:00F0 | 81 81 00 00 A1 81 00 00 81 81 00 0C 81 81 00 00 | ....¡...........
0000:0100 | 7E 7E BF 1A 7E 7E FF FF 7E 7E FF FF 0A 7E FF FF | ~~¿.~~ÿÿ~~ÿÿ.~ÿÿ
0000:0110 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF 0A | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿ.
0000:0120 | 00 00 8D 81 00 00 81 81 70 00 61 81 00 00 81 81 | ........p.a.....
0000:0130 | 00 00 81 D5 00 00 81 81 00 00 81 81 D0 00 81 81 | ...Õ........Ð...
0000:0140 | 7E 7E FF 7E 7E 7E FF FF 7E 5E FF 7E 7E 7E FF FF | ~~ÿ~~~ÿÿ~^ÿ~~~ÿÿ
0000:0150 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿÿ
0000:0160 | 00 00 81 01 00 00 81 81 00 00 81 81 00 00 01 F5 | ...............õ
0000:0170 | 00 00 81 81 20 00 81 81 00 00 81 87 02 00 81 81 | .... ...........
0000:0180 | 7E 7E BF 0B 7E 7E FF FF 7E 7E FF FF 0A 7E FF FF | ~~¿.~~ÿÿ~~ÿÿ.~ÿÿ
0000:0190 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 7E 7E FF 8B | ~~ÿÿ~~ÿÿ~~ÿÿ~~ÿ.
0000:01A0 | 00 01 8D 81 00 00 81 81 50 00 41 81 00 00 81 81 | ........P.A.....
0000:01B0 | 00 00 83 D5 00 00 81 81 00 00 81 81 C0 00 81 C1 | ...Õ........À..Á
0000:01C0 | 7E 7E FF 7F 7E 7E FF DF 7E 5E FF 7F 7E 7E FF FF | ~~ÿ.~~ÿß~^ÿ.~~ÿÿ
0000:01D0 | 7E 7E FF FF 7E 7E FF FF 7E 7E FF FF 5E 7E FF FF | ~~ÿÿ~~ÿÿ~~ÿÿ^~ÿÿ
0000:01E0 | 00 00 81 81 00 00 81 81 00 00 81 81 00 00 01 F5 | ...............õ
0000:01F0 | 00 00 81 81 20 00 81 81 00 00 81 8D 00 00 81 81 | .... ........... |
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chatGPZ
Registered: Dec 2001
Posts: 11114 |
thanks! |
