Search found 588 matches

by dominicbeesley
Thu Aug 16, 2018 10:23 am
Forum: hardware
Topic: Rrad only 8271!
Replies: 6
Views: 198

Re: Rrad only 8271!

It might be worth measuring: a) the actual value of the 150R resistor...they can go low, or high b) the actual voltage on the WRPROT line The chip might not be faulty but the signal might be at the edge or out of the acceptable range and the chip's threshold at the other extreme causing it to misint...
by dominicbeesley
Mon Aug 13, 2018 10:15 am
Forum: hardware
Topic: New Replacement Keyboard Surrounds?
Replies: 14
Views: 1274

Re: New Replacement Keyboard Surrounds?

It doesn't particularly bother me - I think beebs look best when operated sans case. [When I was young you could tell people who really used their machine (as opposed to just play games) by the fact that the screws were not fitted and the lid was stuffed behind the monitor!] That said, my 4 beebs ha...
by dominicbeesley
Tue Aug 07, 2018 10:32 am
Forum: software: other
Topic: cc65 C Cross Compiler
Replies: 22
Views: 1937

Re: cc65 C Cross Compiler

I'll try and do something with the CC65/CA65 Git repository over the next couple of weeks. I'm using da65 to disassemble some stuff at the moment and would like to add some more directives...I hate working witr GitHub but I'll try and get it to a point where I can do a pull request In the meantime h...
by dominicbeesley
Sat Aug 04, 2018 6:20 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 134
Views: 2031

Re: Z80 Protocol Decoder

Kudos to you again dave.

Is this a ground up new application or a suite of processors?

I need to look at this for the 6x09...
by dominicbeesley
Sat Aug 04, 2018 4:44 pm
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

Re: SCSI / SCSI II adapaters?

After a couple of hours grabbed here and there I've got it doing some very basic and no doubt buggy talking across the bus. Here it's run the "inquiry" command on the hard drive.

This seems to take a lot of code...
by dominicbeesley
Thu Aug 02, 2018 6:41 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 86
Views: 6092

Re: New 65C02/W65C816 copro

Impressive! Is there a lot of difference between the wdc/rockwell/other parts? What way does it tend to fail?
by dominicbeesley
Thu Aug 02, 2018 10:55 am
Forum: hardware
Topic: Amstrad Gt64/65 Monitors
Replies: 12
Views: 261

Re: Amstrad Gt64/65 Monitors

Oops yes, brain fade from carrying too many boxes...
by dominicbeesley
Wed Aug 01, 2018 8:54 pm
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

Re: SCSI / SCSI II adapaters?

I can't wait to get the SCSI pins wired up and have a go at programming the thing...
by dominicbeesley
Wed Aug 01, 2018 8:18 pm
Forum: hardware
Topic: Amstrad Gt64/65 Monitors
Replies: 12
Views: 261

Re: Amstrad Gt64/65 Monitors

That's a DC offset problem, try putting a capacitor (1uf or greater - if polarised +ve end towards the beeb). The beeb doesn't include a blocking capacitor...and nor does the amstrad by the looks of things....

At least the sync seems to work!

D
by dominicbeesley
Mon Jul 30, 2018 9:36 pm
Forum: hardware
Topic: Amstrad Gt64/65 Monitors
Replies: 12
Views: 261

Re: Amstrad Gt64/65 Monitors

I seem to recall that the composite out of the bbc could be fed to both the luminance and sync pins to get a picture on these or am I wrong?
by dominicbeesley
Mon Jul 30, 2018 9:28 pm
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

Re: SCSI / SCSI II adapaters?

Thanks Simoni, RobC, I decided to take the plunge and have a go at a SCSI 2* board. I've made a quick start today (between house painting, packing, moving). I've based this round a z53c8003 chip. I've no idea how far I will get with this but it looks interesting, well, to me at least... I didn't get...
by dominicbeesley
Fri Jul 20, 2018 12:44 pm
Forum: hardware
Topic: 80 column teletext
Replies: 30
Views: 2760

Re: 80 column teletext

Thanks Rich "genius" is a bit strong, dabbler is more like it! I can't remember now what happened when I had the pixel clock going too fast for the data clock. I think it did leave blanks (shifting rather than rotating) but I can't recall 100%. Just the other day I pulled the test boards apart (I ne...
by dominicbeesley
Mon Jul 16, 2018 3:17 pm
Forum: hardware
Topic: Tube ULA Reverse Engineering
Replies: 128
Views: 15380

Re: Tube ULA Reverse Engineering

It'd be great to have another open source implementation! Here you go, I've added an Unlicence so if there's anything of any use feel free to help yourselves! I've not got much time to make it pretty but it should all be there https://github.com/dominicbeesley/65816_tube_altera I really should pull...
by dominicbeesley
Mon Jul 16, 2018 2:00 pm
Forum: hardware
Topic: Electron +Plus 1 + AP5 + MMFS question(s)
Replies: 8
Views: 282

Re: Electron +Plus 1 + AP5 + MMFS question(s)

Yes, thanks. I should have looked at the sourcecode first! I wasn't clear whether this was a "replacement support rom" for the plus 1 or a "support rom" for the plus 1 rom (i.e. in addition).

D
by dominicbeesley
Sat Jul 14, 2018 9:52 am
Forum: hardware
Topic: Electron +Plus 1 + AP5 + MMFS question(s)
Replies: 8
Views: 282

Re: Electron +Plus 1 + AP5 + MMFS question(s)

Thanks for all the hints, The problem only presented after a re-boot. After a lot of ROM-swapping I finally tried popping the original Plus 1 ROM altogether and fitted just the JGH/RH Plus One ROM in the AP5 (socket 13) and then everything seemed to work fine. So, to answer my own question: Yes, it ...
by dominicbeesley
Fri Jul 13, 2018 5:53 pm
Forum: hardware
Topic: Electron +Plus 1 + AP5 + MMFS question(s)
Replies: 8
Views: 282

Electron +Plus 1 + AP5 + MMFS question(s)

I've just got an AP5 for my Electron...I wish I could have afforded this and a floppy drive when I was younger! Rather than bombard Dave with questions I thought I'd ask here. I've fitted the Plus 1 expansion ROM from here: https://stardot.org.uk/forums/viewtopic.php?f=3&t=6280&p=59926#p59926 - I pu...
by dominicbeesley
Tue Jul 10, 2018 12:44 pm
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

Re: SCSI / SCSI II adapaters?

Thanks Rob,

So are both the Akhter and Oak Beeb 1MHz bus cards, I've been searching around for info but not finding much

Were all the host adaptors much of a muchness i.e. did they all have the same hardware API to the beeb? I might ditch the 53c8000 idea and just make a SASI interface...

D
by dominicbeesley
Tue Jul 10, 2018 10:13 am
Forum: emulators
Topic: emulator cycle vs walclock vs TIME accuracy
Replies: 8
Views: 520

Re: emulator cycle vs walclock vs TIME accuracy

That's a lot morer fasterer 8) than I'd have expected. I wonder if that is genuinely that much faster or whether that's pushing the accuracy of the timer or overflowing somewhere?
by dominicbeesley
Tue Jul 10, 2018 9:54 am
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

Re: SCSI / SCSI II adapaters?

Thanks Simoni, I'll take a look at your beebSCSI code, I'd not realised it contained an actual SCSI bus that should be very interesting. The drive I've got is a Micropolis 1578, it has its own controller but that seems to support various sector sizes including 256 bytes, though it will probably requ...
by dominicbeesley
Mon Jul 09, 2018 9:38 am
Forum: hardware
Topic: SCSI / SCSI II adapaters?
Replies: 8
Views: 403

SCSI / SCSI II adapaters?

I have been following the Domesday SCSI threads with interest and was wondering what other SASI/SCSI/2 adapters there were for the Beeb/Master. I got a little carried away and bought a SCSI disk (actually SCSI 2 which I'm not sure would even work with the original Master Domesday adapter?). I also h...
by dominicbeesley
Sun Jul 08, 2018 9:41 am
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 86
Views: 6092

Re: New 65C02/W65C816 copro

Sorry, that was a bit terse - I'm pushed for time at the moment moving out of one house while rebuilding another. The way I'd "solved" the clock domain problem was to treat only the available/full flags in the tube registers as mattering in terms of clock domains. I used a flancter to get them from ...
by dominicbeesley
Fri Jul 06, 2018 4:40 pm
Forum: hardware
Topic: New 65C02/W65C816 copro
Replies: 86
Views: 6092

Re: New 65C02/W65C816 copro

You might want to have a look at my TUBE ULA vhdl code I posted further up this thread - the implementation isn't great or full but I used Flancters to decouple the clocks and seemed to work though I never got my board to go much as fast as you're managing! I'll be looking carefully at your DPLL cod...
by dominicbeesley
Thu Jul 05, 2018 10:57 am
Forum: hardware
Topic: Tube ULA Reverse Engineering
Replies: 128
Views: 15380

Re: Tube ULA Reverse Engineering

So as far as I know, the Beeb816 and Matchbox derivative is still the only open source implemetation. I did a simplistic VHDL effort with an eye on BigEd's work for my 65816 experiments a few years ago (2015). I didn't try and make it 100% compatible just good enough to get the thing to work with B...
by dominicbeesley
Wed Jun 27, 2018 12:24 pm
Forum: hardware
Topic: Test ROM
Replies: 60
Views: 1838

Re: Test ROM

I had something like that on one of my beebs and discovered a dry joint and crack around one of the power ground connectors this didn't show up on a simple continuity test but was making for a relatively high inductance ground. I used to have an ESR meter that ran at ~1MHz that was quite good for te...
by dominicbeesley
Tue Jun 26, 2018 11:08 pm
Forum: emulators
Topic: emulator cycle vs walclock vs TIME accuracy
Replies: 8
Views: 520

Re: emulator cycle vs walclock vs TIME accuracy

When changing what speed tests ClockSp tests did you actually LIST the program? Yes, of course I did....I might not have read it _all_ every time though - I've listed it so many times that I've become blind to that part and forgot! :oops: [It doesn't make that much difference on my old test beeb th...
by dominicbeesley
Mon Jun 25, 2018 11:02 pm
Forum: emulators
Topic: emulator cycle vs walclock vs TIME accuracy
Replies: 8
Views: 520

Re: emulator cycle vs walclock vs TIME accuracy

Thanks both, Coesus, I'm pretty sure it's not with interrupts totally disabled, i.e. keyboard wouldn't work to type RUN! However, you seem to be on the right track, selecting "basic hardware only" in BeebEm has brought about something more realistic so there must be one of the hardware devices being...
by dominicbeesley
Mon Jun 25, 2018 12:06 pm
Forum: emulators
Topic: emulator cycle vs walclock vs TIME accuracy
Replies: 8
Views: 520

emulator cycle vs walclock vs TIME accuracy

Hello, I was playing with JGH's clocksp benchmark and noticed that the string manipulation test was spending a lot of time doing floating point divs so I tweaked it to pre-compute the LEN/2 and LEN/4 constants and wanted to re-calibrate the display to a 2.0MHz beeb and gave it a quick run in BeebEm ...
by dominicbeesley
Fri Jun 22, 2018 10:40 am
Forum: software: other
Topic: BBC Micro Compendium by Jeremy Ruston
Replies: 55
Views: 1784

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: 35
Views: 920

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: 35
Views: 920

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...