Posted By
Retroshire
on 2021-03-07
16:55:06
|  CPU replacement compatible with 1551???
OK: another strange observation >
FPGA CPU replacement (Piotr Bugaj) in C16: device not found error
Stock CPU in the same C16: no problem with 1551
the same situation with Plus/4:
FPGA CPU replacement (Piotr Bugaj) in Plus/4: break error
Stock CPU in the same Plus/4: no problem with 1551
IS THE FPGA CPU REPLACEMENT OF PIOTR BUGAJ COMPATIBLE WITH 1551 DISKDRIVE????
Progressive observation: a 2nd 1551 is working fine with FPGA CPU.
Why 1551 no.1 gives a device not found error with fpga CPU and is working fine with stock CPU, while 1551 no. 2 works fine with both FPGA CPU and stock CPU?
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Posted By
marcos64
on 2021-03-08
03:43:51
| Re: CPU replacement compatible with 1551???
I'm having problems too with a CPU replacement and disk drives: The CPU4C16 hangs often with Pets Recue, Slipstream and Majesty of Sprites while loading. With standart kernal or Jiffydos, and with uIEC3 or 1541. But still doing test to narrow the cause.
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Posted By
MCes
on 2021-03-09
04:43:37
 | Re: CPU replacement compatible with 1551???
@marcos64
It's first time that I hear problem like this on my CPU4C16, I'm interested in your test result.
I suppose that you are using a 64k internal ram expansion for play this games, try also the DIAG 264 to be shure of RAM bank integrity.
Remember that (independently of CPU used) for the correct use of jiffydos signals on 264's machines the tape unit cable has to be disconnected by the C16/PLUS4.
Please let me know about your tests, thanks
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Posted By
marcos64
on 2021-03-08
14:05:10
| Re: CPU replacement compatible with 1551???
Everything works but these games. More precisely: the games themselves work well, but they hang while loading. It looks like a problem with the loader used by Bauknecht.
Of course, it may be anything else.
I hope I have time the next days to do a proper final testing, but real life may think different...
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Posted By
Mad
on 2021-03-08
14:47:42
| Re: CPU replacement compatible with 1551???
@marcos64: I hope it's not a bigger problem. We used different loaders in our games. The first game using "Bitfire" was Pets Rescue all former games used "Krills Loader". So at least Majesty of Sprites and Pets Rescue use different loaders.  I have no clue about the whole loader topic, but I think at least that the timing is very critical there. But that's not a topic of a CPU replacement. If you got news I am really curious about that, too.
Maybe it's some sort of other problem like MCes suggested?
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Posted By
marcos64
on 2021-03-09
03:57:32
| Re: CPU replacement compatible with 1551???
Another thing I've noticed with Zador and Alpharay is that sometimes I get infinite lives. Perhaps beacuse I chose Easy level of dificulty? At first I thought that on easy the game gives a lot of extra lives and didn't think about it anymore but yesterday I played Alpharay and definitely it is infinite lives.
I wonder if this is normal?
And the Hiscore doesn't get saved within the same session (I play, enter hiscore and play again, and when I enter a new hiscore the hiscore previously entered does not apear. (Not talking about saving to disk, it doesn't stay in memory).
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Posted By
MCes
on 2021-03-09
07:05:16
| Re: CPU replacement compatible with 1551???
Each CPU4C16 and CPU4PLUS4 use a time-spec selected 6502A processor, and is tested with:
1) loading from tape a auto-turbo game
2) save on tape
------ disconnect tape unit plug from machine ---------
3) 4 times: loading with jiffydos (PAL) a big game from a 1541II.
4) loading with jiffydos (PAL) "Pets Rescue", executing it to arrive at the start of playable part: the presentation make access with own routines to 1541II
I think that this procedure test is able to determine the correct sw/hw compatibility.
Other (simple) test ideas are welcome
SIDE NOTE 1: it's compatible with krills loader since the first final version of the previous "85MC01"
SIDE NOTE 2: a signal noise reduction on board circuits lines can be done plugging it on cpu motherboard socket without the "adapter socket", this way lower the reference ground impedance from motherboard to circuit, normally it doesn't matter but it can be a variable to explore in testing it
----------------------------------------------------
SIDE NOTE 1.2 I remember that during 85MC01 test with krills loader my C16 wasn't able to load from disk aslo with a genuine and wellworking original MOS8501.
The problem was in the KERNAL version: it was the 318004-04 and not the latest version 318004-05.
Burned an EPROM with "-05" version the krills loader worked!
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Posted By
Mad
on 2021-03-09
08:06:24
| Re: CPU replacement compatible with 1551???
@marcos64: Alpharay has unlimited lives in easy level, that's right. Maybe Zador too, not sure about that, would have to check this. The highscores don't stay in memory, they have to be written to disc in almost all games. If I remember right Alpharay has no scores for easy, because you got unlimited lives there. If you get points in easy this is certainly a bug.
In short, yeah unlimited lives in Alpharay are normal in easy mode. And highscores don't stay in memory for any of our games.
Interresting side note 1.2 of MCes. Seems there can be problems with Krills Loader and even normal CPUs.
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Posted By
MCes
on 2021-03-10
05:14:48
| Re: CPU replacement compatible with 1551???
@MAD
I suppose that krills loader use some routine inside kernall without passing through the kernal jump table (maybe that it need only a part of some subroutines...), consequently a different kernal version is potentially a problems generator....
It is my guess.
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Posted By
marcos64
on 2021-03-15
05:28:07
| Re: CPU replacement compatible with 1551???
Well, I've put back in the original PLA and ROMs, installed the NOS TED i bought some months ago and changed the Sharp LH2464-12 (witch works ok on a C64) for NOS OKI M41464-10.
And I used both a 1541 and a 1541-II. A summary of what I've tried:
- Alpharay: Everything OK with the 1541.
- Goonies: it crashed twice with 1541, it works with 1541-II.
- HHGTTG (some modern multisystem interpreter I don't know the name): It worked with the 1541 but didn't with the 1541-II (and I tried 3 times).
- Zador: KO with 1541.
- Majesty of Sprites: KO with 1541 and 1541-II.
- Pet's Rescue: works OK with 1541 and 1541-II.
- Slipstream: KO with 1541 and 1541-II.
So, summarizing: Some ramdom hangs while loading. The same behavior from the begining. It looks like it is more frequent with the Krills Loader but hard to know.
I've put back in the EPROMS, the original TED and the Sharps RAMs because it makes no diference. And will try again with the uIEC3.
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Posted By
MCes
on 2021-03-15
12:47:30
| Re: CPU replacement compatible with 1551???
@marcos64
The easiest way for the next test is to plug into your expanded C16 an original 8501 and repeat the experiment with the games that have problems.
I'm afraid that it can't be done...
Please verify that:
A) your kernal rom MOS318004 is "...-05" (and not less).
B) during disk activity the C16 tape connector has to be free from any plug (no plug/cable/adapter/... connected).
C) Plug the CPU4C16 without the "socket adapter" (remove the extra socket), and please repeat the test.
If you can, please send me the .D64 files with the games that have the most clear errors in the tests: Majesty of Sprites, Slipstream (than I'll test them on my machine).
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Posted By
marcos64
on 2021-03-17
04:29:11
| Re: CPU replacement compatible with 1551???
@MCes
I was thinking too that the only way to be sure is to check it with a real 8501.
A) Yes, it is a -05.
B) Nothing connected to the tape connector when using the 1541 or 1541II. When using the uIEC3, I connect the +5V and GND to the tape connector.
C) I didn't plug the extra socket (I thought it was only to use if the original was of bad quality). So I'll plug it.
All the D64 have been downloaded from here after I received the CPU4C16.
UPDATE 17/3/2021:
With the socket adapter all it happens is a black screen. But I think it is a mechanical problem, the pins of the socket are too thin.
Good thing is that Rabenstein has worked ok with Jiffydos and uIEC3. First try ok, second it hangs, third graphics ok but text corrupted, forth ok. So now I know an easy way of checking. To play and wait it to hang is a real PITA :D
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Posted By
Retroshire
on 2021-03-17
07:10:38
| Re: CPU replacement compatible with 1551???
How is your serialcable? Does it have broken wires inside? Is it earthed on the metal shielding of the plug?
Is your 1541 close to a CRT monitor, then interference might be the problem.
Did you clean the head of your 1541 with IPA?
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Posted By
gerliczer
on 2021-03-17
07:24:10
| Re: CPU replacement compatible with 1551???
Cleaning drive read-write heads with India Pale Ale. How cool is that? 
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Posted By
MCes
on 2021-03-17
11:43:09
| Re: CPU replacement compatible with 1551???
   
The pics are:
1) Slipstream
2) the columns of sockets for tests: TED+CPU=8 sockets (without the motherboard sockets): they make signals more noisy....
3+4) Majesty of Sprites (standard edition)
(tested with 1541)
@marcos64
I don't understand what problem your system is having, the best test is to use an original MOS8501 and test it another time otherwise it will be very difficult to find the problem, I suppose.
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Posted By
Retroshire
on 2021-03-18
05:39:09
| Re: CPU replacement compatible with 1551???
@Gerliczer: that would be nice, but please don't drink too much Isopropanol or you will see no Plus 4 instead of two, haha.
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Posted By
marcos64
on 2021-03-26
04:30:54
| Re: CPU replacement compatible with 1551???
I've notice that my 1541 has a 6502AD, so I swaped it with the 6502A of the CPU4C16. The only difference I've noticed is that Alpharay has hang after I lost the first life.
Now Land of Zador doenst'n load (no matter with which 6502). Strange, it has load previously. But Curse of Ravenstein now works ok every time.
So, everything works ok except it hang sometimes while loading with Jiffydos or a turbo loader. But only with multiload games, it has never failed with single load PRG's.
Hard to come to any conclusion. I let it like this and will see if something different happends.
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Posted By
MCes
on 2021-03-26
13:11:48
| Re: CPU replacement compatible with 1551???
@marcos64
Your experience pushed me to test another time my project and I discovered that a new "lot" of components are more critical than older!
Now I'm improving the noise margin of CPLD internal architecture, in this moment I have a new CPLD revision (1221) that only doesn't work with jiffydos but that load (1541 and 1541II ) also the "Slipstream" and Majesty of Sprites (standard edition).
Modern chips are able to see a very slim noise that old MOS chips ignore, this kind of problems are very depending of chipset/board/components/... all! so it is not simple to reproduce a critical condition for testing the noise problem..
In this period I haven't a lot of time to do it, but I want to try to make it working with jiffydos too. At the end of this improvement activity I'll send you a new CPLD programmed with the last revision.
So I aplogize for all this and I ask you:
1) please use the 6502A that I have provided on CPU4C16.
2) please identify a game that has always problem with my project, then I'll use this game for the tests.
2B) please declare clearly which game is it and where found it:"Land of Zador" may be "Majesty of Sprites 2 - (The Lands Of Zador)" but I don't find it on "plus4world" game database.
Thanks a lot
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Posted By
marcos64
on 2021-03-28
06:01:11
| Re: CPU replacement compatible with 1551???
@MCes Thanks for looking into it!
1) I've already put back in the 6502A.
2) The problem is, it's not always the same game, or at least at the same place, where it hangs.
One that fails a lot is Curse of Rabenstein. I think I downloaded it from here: https://8bitgames.itch.io/rabenstein Its MD5 is: d617b57f33cdfa80d9aa320b908386ba
The MD5 os Slipstream I use is: 356b1e656d6092729821695bcf7c19f6
The MD5 of The Lands Of Zador is eec2e3cb0bf4501fecc83600c2d06b54
Both downloaded from here.
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Posted By
MCes
on 2021-04-01
04:03:51
| Re: CPU replacement compatible with 1551???
  
@marcos64
I remembered what you wrote:
"Good thing is that Rabenstein has worked ok with Jiffydos and uIEC3. First try ok, second it hangs, third graphics ok but text corrupted, forth ok. So now I know an easy way of checking."
The development of the new CPLD release finds a wall with "Rabenstein", so the genius idea: a real MOS8501!
SURPRISE: also with a real MOS8501 the jiffydos is not stable with "Rabenstein" (see pic A for the case of good graphics but not good the text)!
I don't know why it happens, but now it isn't a CPU problem.....
The diagnose/improvement work has already fruits: the signal noise source is the same that on a real 8501 make not usable the jiffydos with (someone?) tape unit connected to the plug (pic B),
it's so true that now the CPU4C16/PLUS4 can use jiffydos also with the tape unit connected (pic C)!
Work in progress, but with a little luck we are close to the end of this new CPLD revision.....
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Posted By
marcos64
on 2021-04-01
08:14:26
| e of RabensteinRe: CPU replacement compatible with 1551???
Curse of Rabenstein has worked OK everytime with the 6502AD. With te 6502A it works sometimes.
BUT, it's always very random. I'm sure if I try more times it will fail.
And it's the same with everything with a turbo multi load. With the 6502AD or the 6502A.
Anyway. don't rush it. I'm fine with it as it is now. A lot better than before
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Posted By
MCes
on 2021-04-11
05:30:41
| Re: CPU replacement compatible with 1551???
@ marcos64
Release "1321" is ready!
It can't do what the original MOS8501 doesn't... (read my previous post)
Improved the noise immunity of the signal present on the port pin.
It work with jiffydos also with multiload, with Krills loader, etc....
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Posted By
marcos64
on 2021-04-16
04:47:57
| Re: CPU replacement compatible with 1551???
@MCes
Is there a way to update my CPU4C16 with the new version?
Anyway, too many problems to deal with in real life... not in the mood at the moment for an intensive testing.
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Posted By
MCes
on 2021-04-18
06:40:22
| Re: CPU replacement compatible with 1551???
@Marcos64
Today I sent to you a new CPLD "1321" programmed....
Have you read my PM (from Amibay)?
12th April 2021
Hi Marcos,
few days and I will send you a new CPLD chip "1321" programmed for your CPU4C16.
For the extraction of the old chip the best solution is the specific tool, but it can be done also with a couple of tiny screwdrivers (or a couple of sewing pins).
Remember to observe the chip orientation before the extraction to plug the new one with the same orientation.
Cheers
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Posted By
marcos64
on 2021-04-29
14:34:56
| Re: CPU replacement compatible with 1551???
@MCes
Sorry, I don't read my email often. And haven't connected to Amibay again.
And thanks for sending the new CPLD.
As soon as I receive it, I'll test it. The C16 is still in my desk although I haven't used it since some weeks.
UPDATE 29/04/2021:
Today I fixed my old PC and was able to use the XE1541 again. I've transferred to real disk 2 demos: Rocket Science and Metamerism.
I tested first Metamerism and no problem. Then I tested Rocket Science and the first time it hung at the "workbench hand with disk" scene. The second time it worked OK. With a 1541 and Jiffydos.
So, still the random fails, it seems.
@MCes
And then, a moment ago, I checked the mail and you letter was there. I try to install it as soon as I found some calm time.
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Posted By
Retroshire
on 2021-04-30
03:56:55
| Re: CPU replacement compatible with 1551???
Rocketscience is not suitable for a 1551, runs only on 1541 and without Jiffydos. Otherwise the workbench logo appears and stays on the screen.
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Posted By
marcos64
on 2021-05-10
06:08:52
| Re: CPU replacement compatible with 1551???
Quick test with the new CPLD.
With the extra socket blank screen. So, I don't use it.
With 1541 and Jiffydos: Rocket Science and Metamerism work ok (only tried once.)
With uIEC3 and Jiffydos: Slipstream doesn't work. Tried 3 or 4 times and it freezes at the begining.
With uIEC3 and normal kernal: Slipstream seems to work ok. I just let it play alone and only push the button were it is necesary to continue but it doesn't hung. For almost 10 times. Un improvement here. Only there is some garbage flashing while loading.
UPDATE 10/5/2021:
Everything with uIEC3.
Lands of Zador: with JD it doesn't load, with kernal I had no problems.
M.O.S: with JD it doesn't load, with kernal I had no problems.
Pet's Rescue: with JD I had no problems loading but it doesn't remember hiscores.
Alpharay: with JD, first try it worked ok, second try it crashed. And it doesn't remember hiscores.
So, I think that it works better with the new CPLD, but hard to be sure, the fails are too random.
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