Sharing my experience of an Atmos resurrection (thread)

In this forum you can write about anything that does not fit in other forums.
This includes generic Oric talkings and things that are totaly unrelated but want to share with people here :)
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jacqu
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by jacqu »

jbperin wrote: Sun Jan 15, 2023 11:15 am Félicitation pour cette réanimation qui contribue à protéger l'espèce. :D
Merci ! Cette espèce est plutôt robuste mine de rien :)
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by ibisum »

This was a great journey to follow and you provided us all with quite some gems! Congrats on the working Atmos and for bringing the joy of that era to this generation too .. something a lot of us old-timers like to see, over and over (at least in my case) ..
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by jacqu »

ibisum wrote: Sun Jan 15, 2023 1:00 pm This was a great journey to follow and you provided us all with quite some gems! Congrats on the working Atmos and for bringing the joy of that era to this generation too .. something a lot of us old-timers like to see, over and over (at least in my case) ..
Thanks for this kind comment :D
Refurbishing this magical toy of our teen years and playing these old games is like a time travel.
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by Chema »

Great story! Thanks for sharing
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by ibisum »

jacqu wrote: Sun Jan 15, 2023 1:17 pm Refurbishing this magical toy of our teen years and playing these old games is like a time travel.
Now that you've gotten things booted up, you must surely enjoy the fact that there is a plethora of TWENTY-FIRST CENTURY Oric titles to explore. Your daughter will *certainly* have something more to think about when you introduce her to some of the, frankly amazing, stuff that has been done since we flipped the century bit.

Seriously, its important to note: the Oric didn't just survive. Its thrived, actually, for decades. Some of the new-school releases are astonishing!
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by Chema »

Nice repair. Thanks for sharing :)
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Re: Sharing my experience of an Atmos resurrection (thread)

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ibisum wrote: Tue Jan 17, 2023 7:59 pm
jacqu wrote: Sun Jan 15, 2023 1:17 pm Refurbishing this magical toy of our teen years and playing these old games is like a time travel.
Now that you've gotten things booted up, you must surely enjoy the fact that there is a plethora of TWENTY-FIRST CENTURY Oric titles to explore. Your daughter will *certainly* have something more to think about when you introduce her to some of the, frankly amazing, stuff that has been done since we flipped the century bit.

Seriously, its important to note: the Oric didn't just survive. Its thrived, actually, for decades. Some of the new-school releases are astonishing!
You’re completely right. I have only recently discovered the incredible extent of work that has been done here to develop new software for this old machine. This gave me the feeling that I stepped in just after the main party. I can't wait to receive my Cumana reborn to play some of the new games available. Thanks to this community for keeping this machine alive. Long live the Oric!
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by Dbug »

The disk drive will really give you an much expended experience :)
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6522 issue fixed

Post by jacqu »

Hi !

This last post to tell you that my VIA issue has been finally fixed. For those of you who did not read this whole lengthy thread, I had a remaining issue with the diagnostic program (https://oric.signal11.org.uk/html/diagrom.htm) failing at the STROBE ACK test. I finally desoldered the 6522 and replaced it with a brand new W65C22N6TPG-14 (https://www.mouser.fr/ProductDetail/955-W65C22N6TPG-14) which should be 100% compatible. And indeed it solved the issue.

It was not a straightforward path though. I stumbled over some fake 6522 chips I bought on eBay. They were branded « MEXIC » instead of « MEXICO », this should have raised a red flag before buying. Furthermore at the back, they were labeled « 6502 » instead of « 6522 ».
BD8FA85C-0ED1-431F-B6C8-9EF83535787A.jpeg
75610AE3-6358-4119-8C2B-7C132D382430.jpeg
As pointed out by someone in another thread of this forum, the diagnostic program gives an error with the new W65C22N6TPG-14 chip at the cassette input test as shown below:
D52356D1-2289-4169-BE1B-313875EC58A8.jpeg
In fact this chip counts more interrupts in average than the original one yielding a failure. I modified the diagnostic program by increasing the upper threshold to 09F9 instead of 0999 as in the 108j version. To do this I simply used an hex editor.

By the way, I tried to compile the ROM from the sources provided by Mike Brown using OSDK, but I did not find a tutorial explaining how to build a ROM. It is probably a simple procedure, but I would be interested by some help.

After inserting the new EPROM in my diagnostic board, all the tests passed. I did some endurance tests using the erebus and the cumana reborn with no issues so far. I think I can call this a success, this Oric is now 100% functional again.
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Re: 6522 issue fixed

Post by Dbug »

jacqu wrote: Sat Mar 04, 2023 10:30 pm By the way, I tried to compile the ROM from the sources provided by Mike Brown using OSDK, but I did not find a tutorial explaining how to build a ROM. It is probably a simple procedure, but I would be interested by some help.
Do you have the link somewhere?

There's no direct support for generating a ROM file, but you can technically just call XA.EXE with the source code and the proper parameters to generate the binary file (I assume it does not need a header) at the fixed address you want.

Assuming the source code is XA compatible, you can probably compile it with something like that:

Code: Select all

%OSDK%\BIN\XA.EXE -C -bt $C000 -o diagnostic.rom diagnostic.s
See the documentation here: https://osdk.org/index.php?page=documen ... =assembler
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Re: 6522 issue fixed

Post by jacqu »

Do you have the link somewhere?
The modified diagnostic ROM that is compatible with a modern 6522 is attached below if you are interested. It has only been tested on one machine, so maybe the modified threshold needs some additional tuning. Feedbacks are welcome.

Mike, thanks for the advice about ROM compilation, I will give it a try.

test108k.zip
(3.68 KiB) Downloaded 52 times
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Re: 6522 issue fixed

Post by iss »

jacqu wrote: Sun Mar 05, 2023 8:22 pmThe modified diagnostic ROM that is compatible with a modern 6522...
@mikeb checks exactly for the value 0x98A. You set the threshold up to 0x9E9, why so much and where from comes the big difference?
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Re: 6522 issue fixed

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iss wrote: Sun Mar 05, 2023 8:47 pm
jacqu wrote: Sun Mar 05, 2023 8:22 pmThe modified diagnostic ROM that is compatible with a modern 6522...
@mikeb checks exactly for the value 0x98A. You set the threshold up to 0x9E9, why so much and where from comes the big difference?
Mike Brown does not check for an exact value, but for an interval (see via.asm):

Code: Select all


	; Check count is about right
	LDA	Z_IRQH
	CMP	#$09
	BNE	vci_f			; High byte is off, fail
	LDA	Z_IRQL
	CMP	#$8A			; < 0x98A? Fail
	BMI	vci_f
	CMP	#$99			; >= 0x999? Fail
	BPL	vci_f
		
	; else PASS
I don’t know why this new IC generates more interrupts, but someone else on this forum made the same observation (I will try to find the thread and report back here). Of course this has to be confirmed by more tests.
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by iss »

Indeed, $98A <= X < $999 vs. yours $98A <= X < $9E9 i.e. threshold $0E vs. $5E or interesting is why difference is so big.
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Re: Sharing my experience of an Atmos resurrection (thread)

Post by jacqu »

iss wrote: Mon Mar 06, 2023 10:47 pm Indeed, $98A <= X < $999 vs. yours $98A <= X < $9E9 i.e. threshold $0E vs. $5E or interesting is why difference is so big.
Yes, this is the big question mark. The diag program generates a 800Hz square signal fed to the cassette input thanks to the loopback plug during 3 seconds. In theory, this would yield 2400 or hex 960 interrupts. Note that the theoretical number of interrupts is not within the interval, but this may be due to an approximate 3s duration. I observed that most of the time, the counting is very deterministic, yielding almost the same value. But sometimes, rarely, it differs a lot from the average value, and when it happens it is always higher than the average. This needs obviously more investigations on other machines before we can draw a conclusion.

I found the thread from @HigashiJun mentioning a failure of the diag program when using newer 65C22 chips:
https://forum.defence-force.org/viewtop ... 494#p23494
Another weird thing is when I launch the excellent DIAGROM (without any add-on cards): with the original VIA fitted, the "timer test" passes but when a 65C22N is inserted, timer test fails.
It is not exactly the same test that fails here, since in my case it is the cassette input test which comes after the two timer tests and shares the same protocol and textual format. Though, I suspect that the « timer test » mentioned by @HigashiJun may refer to the whole section of the diagnostic program dedicated to VIA checking. Not sure, if he reads this, maybe he may give us some clarifications.
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