Search found 561 matches

by dominicbeesley
Fri Jun 22, 2018 10:40 am
Forum: software: other
Topic: BBC Micro Compendium by Jeremy Ruston
Replies: 49
Views: 1268

Re: BBC Micro Compendium by Jeremy Ruston

Hi Dave, I think the algorithms are right, I've been comparing to my BASIC port, which to my chagrin turns out I forked from a 4.00 source not 4.32 (it's about 5 years since I started this and it turns out I started with the wrong disassembly file!). Anyway I was playing with it and wondering why it...
by dominicbeesley
Wed Jun 20, 2018 3:21 pm
Forum: hardware
Topic: My Turbo MMC Misadventures
Replies: 20
Views: 427

Re: My Turbo MMC Misadventures

Not having a go at anyone, just sharing my experiences

Replacing the beebs sockets with turned pins is not a bad idea though...

However, the OP's problem is hopefully sorted!

D
by dominicbeesley
Wed Jun 20, 2018 9:51 am
Forum: hardware
Topic: My Turbo MMC Misadventures
Replies: 20
Views: 427

Re: My Turbo MMC Misadventures

I'd strongly advise against putting turned pin sockets into BBC motherboard sockets. The ones in the beeb are quite soft metal which after thirty odd years is not as springy as it once was. I've had to replace most of the sockets in my main machine, often due to poking in things that I shouldn't! On...
by dominicbeesley
Tue Jun 19, 2018 3:36 pm
Forum: software: other
Topic: BBC Micro Compendium by Jeremy Ruston
Replies: 49
Views: 1268

Re: BBC Micro Compendium by Jeremy Ruston

Thanks Dave, I'll have to check but I suspect that I did...inadvertently - I will have recoded any table addressing stuff, no doubt, to use the 16 bit facilities of the 6809. I just compared with some of the tests https://stardot.org.uk/forums/viewtopic.php?t=10111#p121157 and my port comes out bett...
by dominicbeesley
Tue Jun 19, 2018 3:07 pm
Forum: software: other
Topic: BBC Micro Compendium by Jeremy Ruston
Replies: 49
Views: 1268

Re: BBC Micro Compendium by Jeremy Ruston

I've just stumbled across this thread, I've got a bit of bug chasing to do in my 6809 port of BASIC 4.32. The transcendental functions, I can't remember which but one, gives slightly different results. I ported it more or less blind (i.e. without trying to understand too deeply what was going on) bu...
by dominicbeesley
Tue Jun 19, 2018 2:49 pm
Forum: hardware
Topic: Acorn Domesday AIV SCSI Boards - now free...
Replies: 25
Views: 1072

Re: Acorn Domesday AIV SCSI Boards - now free...

Aha, thanks Simon, that's very helpful! That's given me the leg up I needed. One final question before I print a load of this out to read in bed. Am i right then in thinking that the Beeb SCSI/SASI interface doesn't do the "arbitration" step and that it is always the initiator, or have I got hold of...
by dominicbeesley
Tue Jun 19, 2018 11:48 am
Forum: hardware
Topic: Acorn Domesday AIV SCSI Boards - now free...
Replies: 25
Views: 1072

Re: Acorn Domesday AIV SCSI Boards - now free...

I had a look at the https://www.domesday86.com/?page_id=64 documentation for the interface which is great. By no "decent information" I meant proper standards documentation for parallel SCSI-1 interface, not a criticism of what you have done. What I was hoping for is something that lays out in detai...
by dominicbeesley
Tue Jun 19, 2018 11:17 am
Forum: hardware
Topic: Acorn Domesday AIV SCSI Boards - now free...
Replies: 25
Views: 1072

Re: Acorn Domesday AIV SCSI Boards - now free...

Thanks Simoni, I'd not clocked that PL12 was CMOS, I was hoping a '138 might be enough to interface to the 1MHz bus. It looks like yet another slow burn project for me, first I need to find some decent information on how the low level bus protocol works as it doesn't look as straightforward as IDE! ...
by dominicbeesley
Mon Jun 18, 2018 10:05 pm
Forum: hardware
Topic: Acorn Domesday AIV SCSI Boards - now free...
Replies: 25
Views: 1072

Re: Acorn Domesday AIV SCSI Boards - now free...

I've got a pile of full height SCSI drives to play with soon. Does this plug into the Pl12 connector? Would one of these boards be adaptable to work in a model B by hooking up to the 1MHz bus with a simple address decoder, or maybe I'd be better making something from scratch for the model B? D PS: I...
by dominicbeesley
Mon Jun 18, 2018 10:42 am
Forum: hardware
Topic: Acorn Master and Electron cartridge breakout
Replies: 44
Views: 1122

Re: Acorn Master and Electron cartridge breakout

Got mine, now I can't find my box of scsi cables!

D
by dominicbeesley
Mon Jun 18, 2018 10:42 am
Forum: hardware
Topic: My Turbo MMC Misadventures
Replies: 20
Views: 427

Re: My Turbo MMC Misadventures

The good thing about the beeb is that it is pretty tough. I regularly manage to put chips in the wrong way round etc and so far I've not killed one. When I had Spectrums they seemed to die if you so much as looked at the expansion connector sideways! I use one of these for most of my dip IC removal....
by dominicbeesley
Mon Jun 18, 2018 10:20 am
Forum: hardware
Topic: Master PSU repair - not going well
Replies: 14
Views: 407

Re: Master PSU repair - not going well

Did you check that you put the switch connectors back correctly? Easily mixed up and would produce a nice short circuit when you switch on if they're out by 90 degrees!
by dominicbeesley
Sun Jun 17, 2018 10:50 pm
Forum: hardware
Topic: Meanwell PSU in a model B
Replies: 6
Views: 339

Re: Meanwell PSU in a model B

Hi Tricky, I managed to forget to take pictures. The info here https://www.waitingforfriday.com/?p=794 is a big help. I can't remember the exact dimensions but the brackets were made up from a couple of pieces of scrap MDF. I hand drilled holes and used 20mm long M3 machine screws to mount the new p...
by dominicbeesley
Fri Jun 15, 2018 9:04 am
Forum: hardware
Topic: Meanwell PSU in a model B
Replies: 6
Views: 339

Re: Meanwell PSU in a model B

What brackets though? The only ones I've found were for a master case not model b. Thanks for the hint 're mark and cables, however i got all the crimp tools and connectors ac while bank and have made a custom loom with an extra molex connector and datacentre connector. In the end the brackets only ...
by dominicbeesley
Wed Jun 13, 2018 10:06 am
Forum: hardware
Topic: Hybrid system
Replies: 2
Views: 169

Re: Hybrid system

Yes, some switch cleaner in the cable plugs and clean up the connector pins on motherboard and keyboard gently with a nail-file first. Next, its worth trying carefully cleaning re-seating all the socketed chips, the sockets themselves are worth inspecting. Many of the problems I've had on all the Mo...
by dominicbeesley
Tue Jun 12, 2018 6:59 pm
Forum: hardware
Topic: Meanwell PSU in a model B
Replies: 6
Views: 339

Re: Meanwell PSU in a model B

Yes, thanks, they're the ones I've already got. I've whittled something imperfect from a couple of off-cuts for now.
by dominicbeesley
Tue Jun 12, 2018 4:30 pm
Forum: hardware
Topic: Meanwell PSU in a model B
Replies: 6
Views: 339

Meanwell PSU in a model B

Does anyone know of a source of brackets for fitting a Meanwell PSU into a model B PSU carcass? I got all the bits to put one into my Master but the Rifa's have popped (with only a modest amount of smoke) in my model B this afternoon and I'd like to fit the PSU to the model B as that is the one that...
by dominicbeesley
Mon Jun 04, 2018 2:42 pm
Forum: hardware
Topic: Acorn Master and Electron cartridge breakout
Replies: 44
Views: 1122

Re: Acorn Master and Electron cartridge breakout

A set for me please if there are any left
by dominicbeesley
Sun May 20, 2018 4:55 pm
Forum: hardware
Topic: Screaming CUB monitors
Replies: 10
Views: 501

Re: Screaming CUB monitors

You should try collecting 405 TV's they run at 10Khz which more people can hear. My missus complains if one is on two floors away. 15kHz doesn't seem to bother my 3 year old daughter who watches Peppa pig on my old Decca Bradford TV. Most people became desensitized/used to 15kHz at a young age in th...
by dominicbeesley
Thu May 17, 2018 9:26 am
Forum: hardware
Topic: SASI HDD
Replies: 19
Views: 2254

Re: SASI HDD

I'm afraid I've not done much with SCSI disks. Are you a programmer? Maybe a BASIC program using http://beebwiki.mdfs.net/OSWORD_%2672 and sending the results over the serial port to a PC might be worth a try? I don't know if Phil (Myelin) has any of his serial port cards available - one of these ma...
by dominicbeesley
Wed May 09, 2018 11:07 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 59
Views: 4490

Re: A blitter for the beeb?

Yay FLEX! 20180509_202739-s.jpg This took a bit of work to get going: A 64K linear RAM mode which allows the CPU to address a straight 64K of RAM (switching in 0-8000 from the system when writing to the screen) and a hacked together "mini-MOS" built out of hacked together bits of the 6809 MOS. Then ...
by dominicbeesley
Mon Apr 23, 2018 3:00 pm
Forum: hardware
Topic: SWRAM protection at power down
Replies: 8
Views: 570

Re: SWRAM protection at power down

Yes, I was being over optimistic / stupid, I should have checked it out really. I'd always just assumed that reset _surely must_ get asserted to stop the CPU going daft at switch off and writing to RAM or worse hardware and setting off an erroneous disk write or nuclear war...

D
by dominicbeesley
Mon Apr 23, 2018 10:17 am
Forum: hardware
Topic: SWRAM protection at power down
Replies: 8
Views: 570

Re: SWRAM protection at power down

Thanks Mark, That's kind of what I'd done but I'd assumed that nRESET would go low quickly enough and could use that to then control the chip select signal. [I say kind of what I'd done, I then for some idiotic reason, just before sending the boards off, put in a second inverter that defeated the ob...
by dominicbeesley
Mon Apr 23, 2018 9:54 am
Forum: hardware
Topic: Soldering and Hotair station options
Replies: 38
Views: 1575

Re: Soldering and Hotair station options

This one looks the business https://www.pcb-soldering.co.uk/aoyue-2 ... ation.html

Even looks to have a fume extractor for the soldering iron. I did a lot of soldering this past couple of weeks and the fumes are pretty horrible!

D
by dominicbeesley
Fri Apr 20, 2018 10:52 am
Forum: hardware
Topic: SWRAM protection at power down
Replies: 8
Views: 570

Re: SWRAM protection at power down

Thanks all, This confirms my suspicions. Initially I'd assumed such protection unnecessary - the only SWRAMs I used much were some little Aries(?) plug in single-slot jobbies with no protection and I don't recall them getting corrupted often, if ever. Then again, I probably wouldn't have used them f...
by dominicbeesley
Thu Apr 19, 2018 3:05 pm
Forum: hardware
Topic: SWRAM protection at power down
Replies: 8
Views: 570

SWRAM protection at power down

Hello, I'm having some problems with the SWRAM on the cpu/blit/ram/rom board I'm developing. All works ok until a power-down happens. The processor tends to go a crazy as the power slowly falls off, if a battery backed sideways RAM bank is paged in it can get trampled. The motherboard clock seems to...
by dominicbeesley
Fri Apr 13, 2018 1:03 pm
Forum: hardware
Topic: speaker replacement
Replies: 1
Views: 203

speaker replacement

Hello, To assist developing my soundcard/blitter I've been using an external speaker : 2x4" taken from an old telly in a custom built baffle - well shoved in a cardboard box, connected straight to the beeb's speaker connector. This has served quite well but I decided to try something a bit neater. I...
by dominicbeesley
Fri Apr 13, 2018 12:44 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 59
Views: 4490

Re: A blitter for the beeb?

Although after watching the video, all I could think of was 'speaker in a cardboard box productions' :lol: I was admiring the Sony reference monitors - very nice! Careful though, you’ll be triggering sbadger’s CRT fetish. :lol: But yes, great work Dominic, very interesting. I've had a bit of a Sony...
by dominicbeesley
Fri Apr 13, 2018 10:17 am
Forum: hardware
Topic: Elk advice
Replies: 14
Views: 637

Re: Elk advice

Yes please,

Most of the keys seem to be ok physically, except for L which was always a pain. I think the misbehaviour was down to the plus1 playing up.

D
by dominicbeesley
Fri Apr 13, 2018 10:09 am
Forum: hardware
Topic: A blitter for the beeb?
Replies: 59
Views: 4490

Re: A blitter for the beeb?

Fair enough Phil, I'll maybe hang on to your board for a while before sending, I've not tried it in the Elk and it may need extra physical tweaks to get it to work... The second / even faster serial port(s) on your board would be super-useful. I'm running HostFS on it for the 6809 and using the ACIA...