Search found 544 matches

by simoni
Wed Sep 16, 2020 9:25 pm
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

Right; I'm suffering from spending too much time playing with the AIV SCSI adaptor which has a better design... If the design does use a swing between 0V and 3V, it's not a good design as it wouldn't function if the device used CMOS buffers :) It's possible that the input circuitry on the 74LS240 is...
by simoni
Wed Sep 16, 2020 8:37 pm
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

I'm clearly getting confused! I assumed that when neither end is driving the bus that the terminating resistors would act as a potential divider, which is where I got the 3v from (5v x 330 / (330+220)). Actually, I think you're right there; but it would only float at 3Vs with the cable disconnected...
by simoni
Wed Sep 16, 2020 8:01 pm
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

The pull up/down configuration serves a couple of purposes; as well as terminating they have the effect of pulling the lines up to 5Vs when the cable is disconnected (which is why the values aren't symmetrical) - the SCSI bus is inverted logic, so all 1's is everything 'off'. So on the 5V SCSI bus t...
by simoni
Wed Sep 16, 2020 5:25 pm
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

Which SCSI signal do you consider needs individual control? I don't recall any; pretty much all the SCSI pins should be terminated via pull up/down resistors (so can't by definition be floating).
by simoni
Wed Sep 16, 2020 4:29 pm
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

I could be miles off (working from memory) - but the 74245 is an 8-bit bi-directional buffer with open-drain iirc... it should have a direction pin and a !OE pin - if you disable the outputs they should float... so with 2 control pins from the CPLD (on for direction and one for output enable) you sh...
by simoni
Mon Aug 03, 2020 7:29 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

I'm not a lawyer either; but the statement is pretty clear. Here's a nice PDF with a plain English FAQ on page 4: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/375956/Libraries_Archives_and_Museums.pdf I'm sure that the CfCH are well aware of this.
by simoni
Mon Aug 03, 2020 6:55 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

Yes, I'm sure you do respectfully think that you know more about the subject than I. However you might want to read the text of the copyright exemptions that you so readily refer to; specifically the bit that says "The law requires that the work to be copied for preservation purposes must be an item...
by simoni
Mon Aug 03, 2020 6:07 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

Because I state the archive isn't accessible and you say it is. You imply that my concerns are invalid as we all have access to some magical resource which is just a 'quick email to the right person away' - which isn't the case. Last time I checked, retired BBC employees aren't given the keys to the...
by simoni
Mon Aug 03, 2020 5:32 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

Clearly I need to be more terse:

Are we talking about:

a) the archive (i.e. National/BBC Archive) copies of the PAL Domesday material in a lossless format

or

b) not (a) but something else - like the jpgs I mentioned.

?
by simoni
Mon Aug 03, 2020 4:16 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

Sounds like progress; good for Andy :) By 'ingested images' are we talking about the 696x522 images (lossy compressed with jpeg) made for Domesday Reloaded, or the full PAL images from the tapes?
by simoni
Mon Aug 03, 2020 2:52 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

I don't understand what you mean by "that no one can use"
Clearly we have wildly different ideas of what 'usable' actually means. No matter; since we are drifting totally off topic we'll just have to agree to disagree (again).
by simoni
Mon Aug 03, 2020 1:11 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

I believe the expression coined in the 15th century is "a bird in the hand is worth two in the bush". What 'we' don't have is little advantage compared to the thing we do. Also - there is the argument - which I have placed in front of you time and time again - that Domesday is just two of the AIV di...
by simoni
Mon Aug 03, 2020 12:37 pm
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

Great thing about RF laserdisc preservation is that you can decode and decode - so the current worth of the chroma-decoder in ld-decode vs one no one has access too is a moot point; once/if it's implemented, you simply run ld-decode again and benefit. Recovering the still pictures from the laserdisc...
by simoni
Mon Aug 03, 2020 10:43 am
Forum: 8-bit acorn emulators
Topic: BBC Domesday Emulator
Replies: 28
Views: 1360

Re: BBC Domesday Emulator

I've emailed Andy Finney and the domesday86 folk The DD86 crew is here to help :) I've sent you an email with the details arj. As for 3D support in the PAL transform decoder; it's been implemented - I'd have to check with the dev about the details, but all of the GPLv3 source code is of course avai...
by simoni
Mon Jul 27, 2020 2:09 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm [NOW FULL!]
Replies: 105
Views: 6018

Re: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm [NOW FULL!]

I see that I'm missing a summary for the Domesday86 part II talk... As I mentioned during the last talk, this one will be all about the magic of ld-decode with an in-depth dive into the world of LaserDiscs, how they work and what it takes to build a software defined player. The original inventor of ...
by simoni
Sun Jul 26, 2020 4:49 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm [NOW FULL!]
Replies: 105
Views: 6018

Re: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm

Can you add Ian Smallshire to the list please. He's on a Domesday86 mission for me at the moment and can't do it himself :)

Username: ianSmalls
by simoni
Sat Jul 11, 2020 4:20 pm
Forum: 8-bit acorn hardware
Topic: And then there were - 4!
Replies: 12
Views: 949

Re: And then there were - 4!

That's great; thanks for dumping it - good to know it matches :)
by simoni
Tue Jul 07, 2020 9:13 am
Forum: 8-bit acorn hardware
Topic: And then there were - 4!
Replies: 12
Views: 949

Re: And then there were - 4!

That's a really kind offer on the discs - but I doubt I'd be able to read them without the original player; so (since I'm based in Sweden and the postage wouldn't be super-cheap) it's probably best that I decline. I look forward to the ROM image though :) The IVIS software was supplied on floppy dis...
by simoni
Tue Jul 07, 2020 5:50 am
Forum: 8-bit acorn hardware
Topic: And then there were - 4!
Replies: 12
Views: 949

Re: And then there were - 4!

LDP-1500P makes sense; it was a PAL only Sony from exactly the right time. There is a PAL version of Dragon's Lair too; so the LDP can be used for that (although I don't believe that was the original player used in the PAL cabinets). If it was used in schools it was likely for IVIS discs. The Centre...
by simoni
Mon Jul 06, 2020 9:38 pm
Forum: 8-bit acorn hardware
Topic: And then there were - 4!
Replies: 12
Views: 949

Re: And then there were - 4!

It looks very much like a softoption setup, so I'm guessing the laserdisc player was a VP410? It would be great if you could let me know the type of player and provide a copy of the ROM(s) - I'd like to add the info to the Domesday86 website. If the original system came with any laserdiscs it would ...
by simoni
Mon Jul 06, 2020 2:14 pm
Forum: 8-bit acorn hardware
Topic: BeebSCSI 7_7
Replies: 241
Views: 17839

Re: BeebSCSI 7_7

Yes, there is a new design on github. The case is better looking and also slides together (doesn't need screws like the old one). You can print it in both single and multimaterial. It is designed for a right-angle connector though. The OpenSCAD source code is GPLv3; so you can clone it, play with it...
by simoni
Sat Jul 04, 2020 5:53 am
Forum: acorn atom and acorn system series
Topic: TimeData MZ163 User manual and schematic
Replies: 2
Views: 951

Re: TimeData MZ163 User manual and schematic

It may have taken a few years before it was useful; but eventually it was :)

Glad it helped with the upgrade!
by simoni
Thu Jun 18, 2020 7:49 am
Forum: 8-bit acorn hardware
Topic: New SCSI Host Adaptor
Replies: 121
Views: 6911

Re: New SCSI Host Adaptor

It really depends on what you want to do. You can fork a repo (like BeebSCSI) then branch it; that way if the underlying repo changes you can merge it with you branch. You can have a forked repo as part of your main repo to... so you treat BeebSCSI like a library 'under' your own code. Generally, if...
by simoni
Sat May 16, 2020 1:41 pm
Forum: 8-bit acorn hardware
Topic: Beeb-Bot - A fully 3D printable clone of the BBC Buggy
Replies: 6
Views: 564

Re: Beeb-Bot - A fully 3D printable clone of the BBC Buggy

It's hard to say as I printed lots (and lots) of prototype parts working towards the finished thing. It's not as much as you'd think though since all the component parts are quite small, so I'd say less than a quarter of a reel of each colour (grey and red - for black, even less). You could run it t...
by simoni
Sat May 16, 2020 11:11 am
Forum: 8-bit acorn hardware
Topic: Beeb-Bot - A fully 3D printable clone of the BBC Buggy
Replies: 6
Views: 564

Re: Beeb-Bot - A fully 3D printable clone of the BBC Buggy

Next step: a BBC-driven 3D printer?
Or... a 3D printed BBC driving a 3D printed printer printing a Beeb-Bot :)

Glad you liked the project :)
by simoni
Sat May 16, 2020 9:22 am
Forum: 8-bit acorn hardware
Topic: Beeb-Bot - A fully 3D printable clone of the BBC Buggy
Replies: 6
Views: 564

Beeb-Bot - A fully 3D printable clone of the BBC Buggy

This is not a BBC Buggy and contains no parts from it… This is a Beeb-Bot – a fully open-source, open-hardware 3D printable clone. All parts are backwardly compatible with the original BBC Buggy; you can either print one from scratch (like the one pictured) or use a combination of original and new p...

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