Search found 1398 matches

by BigEd
Sun Oct 22, 2017 12:19 pm
Forum: acorn atom
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1191
Views: 79460

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

Ah, my mistake. I saw 'Rev A' and thought it might be an early board. I see now that Dave has already said he does see the extra capacitors.
by BigEd
Sun Oct 22, 2017 11:56 am
Forum: acorn atom
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1191
Views: 79460

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

I'm not confident from that photo that this board has the extra bypass capacitors on it - and we know that those extra capacitors are needed for stable operation. [Edit: oops, not so] On the subject of the DIP switches, I think I remember Jason saying that they were not all soldered in the same...
by BigEd
Sun Oct 22, 2017 9:27 am
Forum: acorn atom
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1191
Views: 79460

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

If you have any cold spray you could explore to see which part is suffering from heat. Or maybe a finger will tell you that.
https://www.maplin.co.uk/p/maplin-freez ... 00ml-n68an
by BigEd
Sun Oct 22, 2017 8:54 am
Forum: acorn atom
Topic: Matchbox sized 6502 / Z80 / 6809 Co Pro
Replies: 1191
Views: 79460

Re: Matchbox sized 6502 / Z80 / 6809 Co Pro

Do you have a multimeter or other way to check that the Beeb's power supply is putting out a healthy 5 volts?
by BigEd
Fri Oct 20, 2017 9:45 am
Forum: off-topic
Topic: colse wifi ???
Replies: 2
Views: 67

Re: colse wifi ???

close wifi - disable wifi - no wifi
by BigEd
Wed Oct 18, 2017 6:00 am
Forum: general
Topic: Beeb Spotting
Replies: 21
Views: 1574

Re: Beeb Spotting

Four times!
by BigEd
Tue Oct 17, 2017 9:05 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 18
Views: 718

Re: Electron ULA Schematics

Ah, so the MONO signals relate to the monostable using external RC components. We saw two off-sheet connectors because they go to the periphery of the chip - but only to one pin. Maybe.

(Nice one Dave!)
by BigEd
Tue Oct 17, 2017 4:45 pm
Forum: general
Topic: Beeb Spotting
Replies: 21
Views: 1574

Re: Beeb Spotting

Well spotted! At the University of Kent in Canterbury according to a placard:
https://youtu.be/uE5POhMnN78?t=10m11s
and
https://youtu.be/uE5POhMnN78?t=12m7s
by BigEd
Tue Oct 17, 2017 6:43 am
Forum: software: other
Topic: Z80 on a BBC B
Replies: 30
Views: 327

Re: Z80 on a BBC B

(These days I'd recommend the pi-based solution for cost, availability, and convenience in updating: https://github.com/hoglet67/PiTubeDirect/wiki/Level-Shifter-options It's true that there's no physical Z80 chip in there. But it's a piece of hardware you plug into your Beeb and it runs exactly like...
by BigEd
Tue Oct 17, 2017 4:42 am
Forum: general
Topic: Beeb Spotting
Replies: 21
Views: 1574

Re: Beeb Spotting

Oh, found the one and only gold-plated Beeb in the virtual Science Museum!
https://goo.gl/maps/QTJiL6sgqdE2
by BigEd
Mon Oct 16, 2017 9:33 pm
Forum: general
Topic: Beeb Spotting
Replies: 21
Views: 1574

Re: Beeb Spotting

Spotted a Beeb at 9:50 in this walkaround of last year's Vintage Computer Festival in Zurich:
https://youtu.be/yyTZtli-mlc?t=9m50s
by BigEd
Mon Oct 16, 2017 4:52 pm
Forum: bbcmicro.co.uk
Topic: search and alternative versions
Replies: 41
Views: 1058

Re: search and alternative versions

Certainly worth mentioning it's an 8 bit micro from Acorn. I'd probably make 'request' the link, not 'BBC'.
by BigEd
Mon Oct 16, 2017 1:51 pm
Forum: general
Topic: Adventures for your BBC micro BOOK on eBay
Replies: 24
Views: 365

Re: Adventures for your BBC micro BOOK on eBay

The archive.org approach managed to get these two lines out of that distorted image:

Code: Select all

690 S=S-5
700 RETURN

I would think a conventional scan of that would work well.
by BigEd
Mon Oct 16, 2017 1:32 pm
Forum: hardware
Topic: 6502 second processor poll
Replies: 38
Views: 883

Re: 6502 second processor poll

If you planned to make a game for a second-processor equipped machine, you might be interested in how many people are an in a position to appreciate it.

For some purposes, the proportion matters, and for others, the absolute number. For other purposes, it's all just a bit of fun.
by BigEd
Mon Oct 16, 2017 9:48 am
Forum: bbcmicro.co.uk
Topic: search and alternative versions
Replies: 41
Views: 1058

Re: search and alternative versions

The important thing is to be found by search engines - a descriptive title is a big win there.
by BigEd
Mon Oct 16, 2017 7:14 am
Forum: general
Topic: Adventures for your BBC micro BOOK on eBay
Replies: 24
Views: 365

Re: Adventures for your BBC micro BOOK on eBay

BTW, if you upload a zip of page images to archive.org, they will - OCR - convert to PDF, to text file and to ebook - display a flipbook - host everything and all for free. All you really need to know is to name the zip file to match *_images.zip Images can be jpg, png, or quite possibly other forma...
by BigEd
Sun Oct 15, 2017 6:09 pm
Forum: projects
Topic: Cowgol: actually a thing
Replies: 12
Views: 364

Re: Cowgol: actually a thing

Interesting to know - thanks for the measurements. I'm going to suppose you're in the first part of "make it work first, then make it work fast!" Having something which works is no mean feat - well done!
by BigEd
Sun Oct 15, 2017 6:07 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 19
Views: 386

Re: Open Source Logic Analyzer Experiments

This is an excellent thing Dave!
by BigEd
Sun Oct 15, 2017 1:50 pm
Forum: projects
Topic: Cowgol: actually a thing
Replies: 12
Views: 364

Re: Cowgol: actually a thing

Presumably it's not helping that you're also compiling the support library from source. Is the setup such that it could be compiled once, and linked in at a late stage?
by BigEd
Sun Oct 15, 2017 9:41 am
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 19
Views: 386

Re: Open Source Logic Analyzer Experiments

Actually thinking about it while going back would be great. Just setting the JSR address to the two writes gives the user in the disassembly the clue of where you have come from. Might also be worth checking the address stored with the predicted address when you think you know that the instruction ...
by BigEd
Sat Oct 14, 2017 9:47 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 19
Views: 386

Re: Open Source Logic Analyzer Experiments

Ha ha - I walked into that! A classic "how hard can it be" moment.
by BigEd
Sat Oct 14, 2017 9:36 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 19
Views: 386

Re: Open Source Logic Analyzer Experiments

this is amazing work. The pc calculation is very clever. You could also work backwards [once] you know the first true address to fill in the blanks as the JSR stacks where you currently are, the same for IRQ. actually I think a double or triple write will contain the address of where you currently ...
by BigEd
Sat Oct 14, 2017 5:49 pm
Forum: emulators
Topic: MAME: Tube devices
Replies: 50
Views: 1964

Re: MAME: Tube devices

Thanks!
by BigEd
Sat Oct 14, 2017 11:27 am
Forum: emulators
Topic: MAME: Tube devices
Replies: 50
Views: 1964

Re: MAME: Tube devices

Thanks
[WINDOW ONLY, NON-SDL] Fast forward. While held, runs game with
throttling disabled and with the maximum frameskip.

Would that speed up floppy access too? Or just CPU? I was thinking of something which would speed up floppy access but not CPU.
by BigEd
Sat Oct 14, 2017 11:13 am
Forum: emulators
Topic: MAME: Tube devices
Replies: 50
Views: 1964

Re: MAME: Tube devices

Well, I'm a user of MMFS - but it would be easier, I would think, just to zero out the modelling of floppy head movement and rotational delay, and stick with DFS. Either would do, just to speed up file access, for those uses where file access is a limiting factor... I'm thinking of Cowgol although F...
by BigEd
Sat Oct 14, 2017 11:01 am
Forum: emulators
Topic: MAME: Tube devices
Replies: 50
Views: 1964

Re: MAME: Tube devices

(Can MAME emulate solid state storage? Or infinitely fast floppies, which is probably about the same thing?)
by BigEd
Fri Oct 13, 2017 5:43 pm
Forum: projects
Topic: Cowgol: actually a thing
Replies: 12
Views: 364

Re: Cowgol: actually a thing

A very good point - applies also the Matchbox, for those running an up to date release of the design. Same I/O interface for the banking.
by BigEd
Fri Oct 13, 2017 5:40 pm
Forum: hardware
Topic: 6502 second processor poll
Replies: 38
Views: 883

Re: 6502 second processor poll

(Way back in December, Kjell had already shipped over 100 converter boards for PiTubeDirect users - with some ten months of sales since then, the numbers of people with access to 6502 second processor function must be pretty high now.)
by BigEd
Fri Oct 13, 2017 5:36 pm
Forum: projects
Topic: Cowgol: actually a thing
Replies: 12
Views: 364

Re: Cowgol: actually a thing

I believe Alan Cox felt the MOS performance was too slow to support a comfortable Fuzix experience. You are, by the sound of it, pushing the file system hard too. As you say, some buffering (or other intelligence) at the application level could make a big difference. Many - perhaps most - modern use...
by BigEd
Fri Oct 13, 2017 9:46 am
Forum: for sale / freebies
Topic: BeebSCSI mini
Replies: 61
Views: 3409

Re: BeebSCSI mini

flynnjs wrote:Even I was surprised. I've added another 10 on the shop.

A very successful project!

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