Search found 426 matches

by tom_seddon
Sun Oct 18, 2020 9:57 pm
Forum: archive requests
Topic: DataGem by Gemini
Replies: 11
Views: 1093

Re: DataGem by Gemini

I've got the ROMs for this. No other materials, though - no carrier board, no manual, no disks!

One ROM appears to be just FFs, so I assume it's erased itself over the years. The other is a match for Bill's encrypted DataGem 2039 B.

--Tom
by tom_seddon
Thu Oct 15, 2020 3:40 pm
Forum: 8-bit acorn emulators
Topic: 6502 cycle-level instruction detail
Replies: 19
Views: 506

Re: 6502 cycle-level instruction detail

The Synertek 6502 hardware manual (there's a copy on 6502.org) has tables at the back for the bus accesses for each type of instruction.

--Tom
by tom_seddon
Fri Oct 09, 2020 3:29 pm
Forum: 8-bit acorn hardware
Topic: Technomatic Newbie Eprom Programmer Saga
Replies: 5
Views: 174

Re: Technomatic Newbie Eprom Programmer Saga

just installed a Technomatic EPROMER II Eprom Programmer into BBC Model B and software disk installed on MMC drive. Looks like you have an undumped version of Epromer II v2.5, we currently only have v2.3 archived. Would yo be able to dump it and attach here? It might be $.rprom2 on the disk I poste...
by tom_seddon
Tue Sep 15, 2020 8:24 pm
Forum: programming
Topic: Using a Mac or PC for BBC games authoring
Replies: 45
Views: 1480

Re: Using a Mac or PC for BBC games authoring

having managed to get an SSD image working on WIndows, I have almost got it on the Mac. I can't seem to get BeebEm or b2 to automatically reload the disc. In the case of BeebEm on the Mac, I get an error: "The document “droid.ssd” could not be opened. BeebEm5 cannot open files in the “DocumentType”...
by tom_seddon
Sat Sep 12, 2020 11:39 pm
Forum: programming
Topic: Zalaga
Replies: 5
Views: 435

Re: Zalaga

Searching this site there seem to be issues in the past with the game using 65C02 op codes, but my beeb has a 65C02, but the beebem setup I used was bog standard. I think Zalaga uses 6502 illegal opcodes & therefore (unpatched) doesn't work on a 65C02. I believe it doesn't run on a Master for the s...
by tom_seddon
Wed Sep 09, 2020 1:00 am
Forum: programming
Topic: Using a Mac or PC for BBC games authoring
Replies: 45
Views: 1480

Re: Using a Mac or PC for BBC games authoring

This is the sort of workflow b2 is designed to (hopefully) work well with. The way I do this on Mac OS is to use the HTTP API, as documented (if perhaps a bit tersely...) here: https://github.com/tom-seddon/b2/blob/master/doc/Debug-version.md#http-api The intended workflow here is to leave b2 perman...
by tom_seddon
Wed Sep 09, 2020 12:30 am
Forum: scanning of books, magazines, ads and letters
Topic: BBC Master Reference Manual [Remastered PDFs]
Replies: 7
Views: 602

Re: BBC Master Reference Manual [Remastered PDFs]

+1 - this is great, thank you. An excellent (and searchable) replacement for the enormous PDF (of not-quite-aligned images) that I've been using so far!

--Tom
by tom_seddon
Thu Sep 03, 2020 11:50 pm
Forum: programming
Topic: The NMI is (almost) a lie!
Replies: 2
Views: 288

The NMI is (almost) a lie!

The CMOS CPUs have a lot of NOPs, with the 1 cycle ones being particularly interesting. 1-cycle instructions aren't super easy to fit into the 6502's execution model, so clearly a bit of shoehorning was required, and they had to shave off some bits to make them fit. Like the bit where it checks for ...
by tom_seddon
Fri Aug 28, 2020 11:17 pm
Forum: 8-bit acorn hardware
Topic: Looking for a cheap BBC B
Replies: 16
Views: 1505

Re: Looking for a cheap BBC B

I have a BBC B issue 3 and issue 7 PCBs, is there a document that details the changes in the BEEB PCB versions? There's a summary in the BBC Micro Service Manual Oct 1985 Section 1, available from Chris's Acorns: http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Manuals.html#SM Not ment...
by tom_seddon
Thu Aug 27, 2020 9:11 pm
Forum: off-topic
Topic: Rapid not selling 60/40 to general punters anymore?
Replies: 24
Views: 1422

Re: Rapid not selling 60/40 to general punters anymore?

It's not the requested brand, but you can get lead solder from https://www.cricklewoodelectronics.com/Solder-60-Tin-40-Lead-0.7m-diameter-100grams.html I also bought some from Amazon - https://www.amazon.co.uk/gp/product/B0001P0GLW - but it's rather expensive, even if it did arrive quickly. Seems a ...
by tom_seddon
Wed Aug 26, 2020 12:37 am
Forum: 8-bit acorn hardware
Topic: BBC Model B - new keyboard connector?
Replies: 25
Views: 816

Re: BBC Model B - new keyboard connector?

I use dupont cable, about 25 cm long... doesn't seem to be a problem. I think my setup involves 3 strips of stuck-together wires, so it's not too much of a forest inside. Though it does look a bit messy. Unplugging the keyboard is a lot more hassle, as there's no longer just one solid plug you can p...
by tom_seddon
Tue Aug 25, 2020 3:35 pm
Forum: 8-bit acorn emulators
Topic: MAME: Emulating FDC Boards
Replies: 62
Views: 9585

Re: MAME: Emulating FDC Boards

Pernod wrote:
Sat Aug 15, 2020 1:44 am
We currently only have a dump of UDM DDFS 2.00. There are earlier versions out there if anyone has one, specifically looking for 0.98 and maybe 1.1.
Beeb apparently with UDM DFS 1.10 up for sale on eBay: https://www.ebay.co.uk/itm/BBC-32K-micr ... 4415544379

--Tom
by tom_seddon
Sat Aug 22, 2020 11:47 pm
Forum: programming
Topic: A new BBC Micro MOS Reassembly
Replies: 32
Views: 1636

Re: A new BBC Micro MOS Reassembly

JGH has the beginnings of a Master MOS disassembly here: http://mdfs.net/Info/Comp/Acorn/Source/MOS.htm - I haven't been through it in any great detail, but it looks like it covers the key parts of Terminal and MOS, and he's disentangled some of the tables and added some commentary for MOS 3.20. I'v...
by tom_seddon
Sat Aug 22, 2020 9:37 pm
Forum: 8-bit acorn software: other
Topic: What's wrong with OSGBPB?
Replies: 23
Views: 1081

Re: What's wrong with OSGBPB?

Should do - the FDC consumes or produces 1 byte per ~64 µsec or so, so you can presumably use Tube transfer modes 0 or 1 (the slowest but most convenient bulk transfer methods). --Tom P.S. BeebLink's OSGBPB runs at full OSFILE speed (and a good thing too, because its OSBGET/OSBPUT throughput is terr...
by tom_seddon
Sat Aug 22, 2020 1:21 am
Forum: programming
Topic: A new BBC Micro MOS Reassembly
Replies: 32
Views: 1636

Re: A new BBC Micro MOS Reassembly

try: https://tobylobster.github.io/mos/os120_acme.a This works for me, trying it just now on my Mac. The links on the site don't work for me, though, either on my Mac (tried just now) or my work PC (tried earlier). --Tom P.S. the web version at https://tobylobster.github.io/mos/mos/index.html works...
by tom_seddon
Fri Aug 21, 2020 12:54 am
Forum: 8-bit acorn emulators
Topic: b2 - new emulator
Replies: 170
Views: 19624

Re: b2 - new emulator

Sorry this doesn't work as-is! - b2 doesn't really support the Raspberry Pi, partly because I don't have a modern one, and partly because I'd assumed (correctly, it sounds like...) that performance would be terrible anyway. But since it looks like it probably won't actually be all that much work, I'...
by tom_seddon
Mon Aug 17, 2020 11:13 pm
Forum: 8-bit acorn hardware
Topic: Beeb Issue 3 Questions
Replies: 2
Views: 222

Re: Beeb Issue 3 Questions

The red socket with the link between pins 9 and 12 will probably be to do with the disk interface - the Acorn 1770 interface comes with a (much lower tech) little staple to do exactly the same thing, if you've no IC in that socket. I'm not sure exactly what it does, but symptoms when I mis-installed...
by tom_seddon
Fri Aug 14, 2020 2:57 am
Forum: 8-bit acorn hardware
Topic: Corroded Master 128 battery plug
Replies: 3
Views: 254

Corroded Master 128 battery plug

The metal bits inside the plug for my Master's battery pack have transformed themselves into unconductive green gunk. I need to replace the plug... what should I buy to replace it? Do I buy some specific item, or will any 3-pin SIL connector do the job? Also - is this green stuff, presumably oxidize...
by tom_seddon
Sat Aug 08, 2020 12:45 am
Forum: for sale / freebies
Topic: VideoNuLA boards
Replies: 157
Views: 28353

Re: VideoNuLA boards

I'm interested in a NuLA board if there's any currently available!

--Tom
by tom_seddon
Wed Aug 05, 2020 12:00 am
Forum: 8-bit acorn hardware
Topic: Watford Electronics 16K SWR
Replies: 1
Views: 281

Re: Watford Electronics 16K SWR

I added some wires, and attached them to the appropriate address pins of the CPU, and the device seems to be working as expected... I am now pretty certain it came with 28 pins originally :lol: Since there's no obvious info on the internet about this particular item, here are some notes for the bene...
by tom_seddon
Tue Aug 04, 2020 2:28 am
Forum: 8-bit acorn hardware
Topic: Watford Electronics 16K SWR
Replies: 1
Views: 281

Watford Electronics 16K SWR

Anybody got one of these, and/or a manual? (All I've got is the board, and some handwritten notes.) Untitled.png Mine is missing pins 15 (data bit 3), 4 (address bit 6) and 25 (address bit 13)... is it supposed to be like that? Surely not! There's a flying lead to connect the board to pin 8 of IC77,...
by tom_seddon
Mon Aug 03, 2020 1:18 am
Forum: 8-bit acorn hardware
Topic: Master 128 Issue 1/2 differences
Replies: 9
Views: 478

Re: Master 128 Issue 1/2 differences

I've got an issue 2 Master. If you don't get any better offers, I'll try taking some close up daylight shots with my phone's camera and see if they stitch together OK.

--Tom
by tom_seddon
Sat Aug 01, 2020 12:29 pm
Forum: 8-bit acorn hardware
Topic: Dead BBC B with apparent 81LS95 problem
Replies: 14
Views: 916

Re: Dead BBC B with apparent 81LS95 problem

Yes probably a faulty socket. That's why 1024MAK always says test from chip leg to chip leg where possible. Did any of the earlier chip replacements help or was it just the CRTC bad traces all along? Bad CRTC traces, a bad trace in the memory addressing logic, and a faulty IC45 (74LS139). Broken IC...
by tom_seddon
Sat Aug 01, 2020 11:30 am
Forum: 8-bit acorn hardware
Topic: Dead BBC B with apparent 81LS95 problem
Replies: 14
Views: 916

Re: Dead BBC B with apparent 81LS95 problem

Regarding ROM socket 14 (IC100) - wrote some code to cycle through accesses to the ROM slots. IC20 pins 9-12 chip select outputs looked fine, but the corresponding pin 20 inputs were only going low for the chips in sockets 12, 13 and 15. Narrowed down to what I assume is not-quite continuity between...
by tom_seddon
Fri Jul 31, 2020 8:50 pm
Forum: 8-bit acorn hardware
Topic: The latest broken beeb repair
Replies: 40
Views: 1312

Re: The latest broken beeb repair

Colday wrote:
Fri Jul 31, 2020 4:28 pm
@tom_seddon

Well, I have managed to locate a place in the UK that has some in stock, I am waiting for a quote.
Thanks - sounds good.

Regarding @, i don't think the forum understands it - i think people only get notified if you quote reply their post or reply to a thread they created.

--Tom
by tom_seddon
Fri Jul 31, 2020 4:18 pm
Forum: 8-bit acorn hardware
Topic: The latest broken beeb repair
Replies: 40
Views: 1312

Re: The latest broken beeb repair

I checked with Mark at RC, he has no spare beeb RAM currently so I will be making an order with the United States of Murica! I'll open this up, does anyone else want to tag along with my order? Might do, I should probably get some spares as these don't seem particularly widely available. Feels like...
by tom_seddon
Fri Jul 31, 2020 1:12 am
Forum: archive submissions
Topic: Various 32K ROMs
Replies: 10
Views: 826

Re: Various 32K ROMs

Interestingly, Beebug's Master ROM carrier board's PAL chip is marked "IWORD". Thanks for these. The Master ROM 1.05 was previously undumped, dumped versions are 1.01 and 1.03. This actually uses the same carrier board PAL as Inter-Base. Of note is this version is dated 1991 whereas previous versio...
by tom_seddon
Thu Jul 30, 2020 10:55 pm
Forum: 8-bit acorn software: other
Topic: TECHNOMATIC EPROMER II EPROM PROGRAMMER
Replies: 6
Views: 1210

Re: TECHNOMATIC EPROMER II EPROM PROGRAMMER

Here's an ssd and adl of what claims to be EpromRyter 3.3 - "(c) 1986 GsoFt 11/87 V3.3".

The original was an ADFS disk, hence the adl file.

I've got a manual for this that looks to be slightly different from the one Dave posted. I'll get it scanned at some point.

--Tom
by tom_seddon
Wed Jul 29, 2020 11:11 pm
Forum: 8-bit acorn hardware
Topic: Dead BBC B with apparent 81LS95 problem
Replies: 14
Views: 916

Re: Dead BBC B with apparent 81LS95 problem

I assume I could just solder some wires on the bottom of the motherboard, and that'd fix it? The fix way is just put some wire point to point on the bottom side of the board. If you have lots of time you can hunt the breaks/bad vias down and repair them almost invisibly. It takes some practice. Wir...

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