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by RobC
Sun Feb 18, 2018 12:49 pm
Forum: emulators
Topic: When should keyboard interrupts be enabled during startup?
Replies: 4
Views: 65

Re: When should keyboard interrupts be enabled during startup?

hoglet wrote:I have a suspicion the keyboard status is normally polled off the 100Hz timer interrupt.

Yes - the System VIA Timer 1 is set to go off every 10ms and this triggers the polling of the keyboard.
by RobC
Fri Feb 16, 2018 8:38 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

The Oric is another one I've emulated! Unfortunately it doesn't have 8x1 attributes, it has 6x1 Ah! I just saw that attributes could be changed per scanline and assumed they were 8x1. I did own an Atmos for a bit so should have paid more attention! (EDIT2: it's only 240 pixels across though, so if ...
by RobC
Fri Feb 16, 2018 5:43 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

The Camputers Lynx may be easier than the CPC, it also uses a 6845. Not so much software out there for it though. I have a Lynx and think it can do 8 colours at something like 256x256 with no attribute clash. Again, the 12MHz attribute mode might get close but it's not quite good enough. And as you...
by RobC
Fri Feb 16, 2018 5:01 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Thanks Thomas - I'll take a look at those games. Also, the info on the CPC is very useful as I'm not very familiar with it apart from knowing that it uses a 6845! I'd thought about the MSX-type machines as I have an Einstein and know a little bit about it. The sprites are a problem as each can have ...
by RobC
Fri Feb 16, 2018 1:54 pm
Forum: hardware
Topic: Music 5000 - sound generation
Replies: 12
Views: 357

Re: Music 5000 - sound generation

On a semi-related note, would it have been possible to intercept OSWORD 7 and OSWORD 8 to use a different chip... Yes - see here for an implementation that sends SOUND commands to a MIDI interface: http://mdfs.net/Software/MIDI/ A while back, I used it with a home-made MIDI interface and a Yamaha k...
by RobC
Fri Feb 16, 2018 11:24 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

I was hoping that NuLA could control it and that a NuLA reset could be used to reset the frame, but I guess not. Unfortunately, all the sync stuff is controlled by the 6845. The Video ULA just outputs the serialised data and continues to do so unless told not to by the DISEN signal. I'll try to fin...
by RobC
Fri Feb 16, 2018 11:07 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

It's only interlace, but the user manually has to choose to swap the fields if they are the wrong way around unless some one has found a way to detect which field is showing. Rob, does NuLA know which field is showing/can it set it? I have a vague recollection that someone found that the timing of ...
by RobC
Thu Feb 15, 2018 9:38 pm
Forum: hardware
Topic: Music 5000 - sound generation
Replies: 12
Views: 357

Re: Music 5000 - sound generation

I wouldn't expect to see it used as a sound peripheral for a game. There a quote from Nick "Orlando" Pelling about using the Music 500 in Firetrack 2 in the Lost & Found section of the Stairway to Hell site. He basically says the same thing - it just takes up too much of the CPU's tim...
by RobC
Thu Feb 15, 2018 2:47 pm
Forum: hardware
Topic: Myelin's in-system updateable MegaROM for the BBC Master 128
Replies: 14
Views: 583

Re: Myelin's in-system updateable MegaROM for the BBC Master 128

jgharston wrote: Just need somebody to unsolder my VULA and socket it.

I'll to do it if you're happy to cover P&P. Royal Mail charge £4.40 each way for 1st class/signed for if you just send the PCB in cardboard and bubble wrap...
by RobC
Thu Feb 15, 2018 12:10 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

I've heard of someone using the BBC Master shadow memory in order to double the vertical resolution with interlacing. Yes - I remember typing in a program that did this from Acorn User. Unfortunately, my monitor wasn't happy with it (or maybe I made a typo!) If you search on 8bs for GLM PD disk 8, ...
by RobC
Thu Feb 15, 2018 6:48 am
Forum: hardware
Topic: Running DosPlus (version 2.1) with Raspberry Pi 80286 processor emulator on BBC master 128.
Replies: 33
Views: 1480

Re: Running DosPlus (version 2.1) with Raspberry Pi 80286 processor emulator on BBC master 128.

I have a CF/HD disk image that comes from an install I did from floppies onto my DC. Haven't tried using BeebSCSI yet so don't know whether it can use the same disk images (.dat) but I can send you a link to my disk image if you want. Also, if you've got ADFS explorer, you can browse files and see t...
by RobC
Wed Feb 14, 2018 11:58 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Sorry - calling it "shadow screen memory" was misleading. According to this (and other sources I've found), the CPC can display screen data from any address in its 64KB RAM and use it for double buffering etc.: http://www.irespa.eu/daan/lib/howtoCPCemu.htm I need to think whether this is g...
by RobC
Wed Feb 14, 2018 8:43 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Thanks Rich - I've only just started looking into it as I don't know too much about the CPC. The similarities between the hardware made me think that it's worth exploring. The Spectrum emulator already has a mechanism for timing host actions (e.g. border and sound) based on the number of tstates so ...
by RobC
Wed Feb 14, 2018 7:49 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Thanks tricky - I'll give it a go. I notice that a lot of downloadable snapshot games are in .z80 format and not the .sna format used by SpectROM. Thanks for the tip Ken. I could add .z80 support if required as I only chose .SNA because I had a CD full of them - I think it came with the !Z80Em emula...
by RobC
Tue Feb 13, 2018 8:33 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

remember to set the sound volume to silent... Thanks tricky. Presumably this is the volume for tone generator 1 rather than the noise channel? It should be fairly easy for me to try this out so I'll give it a go in the next day or so. (I've just started looking at a CPC emulator so that's taking up...
by RobC
Tue Feb 13, 2018 7:18 pm
Forum: introduce yourself
Topic: new to BBC
Replies: 11
Views: 207

Re: new to BBC

Welcome.

I've managed to find an old link to the Windows MMBImager software via the Wayback machine:
https://web.archive.org/web/20161115035534/https://swhs.home.xs4all.nl/bbc/mmbeeb/windows.html

Not sure if there are later versions though...
by RobC
Tue Feb 13, 2018 1:42 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Rob, have you tried using "periodic noise" with the frequency controlled by the sound channel for lower frequencies? Hi tricky. I haven't - could you explain how this would work as I'm not familiar with the concept? I've tried PCM with frequency set to the highest value and volume based o...
by RobC
Tue Feb 13, 2018 12:40 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

This is working pretty amazingly well Rob, very impressive Thanks - I'm really pleased with how well it works :D The true star is the Pi co-pro as it does all the heavy lifting. Even the audio sounds great. It works better in some games than others - the speech in Ghostbusters is intelligible but t...
by RobC
Mon Feb 12, 2018 10:17 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

Thanks for pointing that out Dave. Not sure how it got corrupted but it looks like the README file has overwritten part of the ROM image. It should be okay again now. (It's better to use the version from the Dropbox link as it fixes a couple of keyboard handling issues...) There are some SNA files a...
by RobC
Mon Feb 12, 2018 7:52 pm
Forum: upcoming and recent events & exhibitions
Topic: RISC OS SouthWest Show 2018 - Saturday 24th February, 2018
Replies: 2
Views: 238

Re: RISC OS SouthWest Show 2018 - Saturday 24th February, 2018

I took some Beebs along last year and could do the same again. The Beebs generated a bit of interest but it meant I didn't get to see as much of the show as I'd done in previous years... If there's enough interest, I could ask for a table again and have the Spectrum emulator running just to confuse ...
by RobC
Mon Feb 12, 2018 11:04 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3270

Re: SpectROM - Speccy emulator for the Pi co-pro

I've updated the VideoNuLA support pack to document the new Spectrum and Thomson attribute modes and have added the latest version of the SpectROM emulator. It can be downloaded from Dropbox via the following link: https://tinyurl.com/y75cmrxe This corrects a couple of bugs in the keyboard handling ...
by RobC
Sat Feb 10, 2018 1:24 pm
Forum: hardware
Topic: Screen shadow memory
Replies: 18
Views: 513

Re: Screen shadow memory

I think the IntegraB board adds shadow RAM in a similar way to the B+ but I'm not sure there's anything that does it in the same way as the Master (i.e. having two banks available for display). I guess the connections to the 6845 are a problem or it would have been before. It would be a useful upgra...
by RobC
Fri Feb 09, 2018 12:08 pm
Forum: hardware
Topic: Kempston Competition Pro
Replies: 12
Views: 255

Re: Kempston Competition Pro

Lardo Boffin wrote:And it works! Wow. I really suck at Commando. Garish!

Glad it works.

You can sort out the Commando colours with VideoNuLA :wink:

I've been playing the Spectrum version under SpectROM and the game's better but the colours are still not the best!
by RobC
Fri Feb 09, 2018 11:36 am
Forum: hardware
Topic: Kempston Competition Pro
Replies: 12
Views: 255

Re: Kempston Competition Pro

Try Commando or Firetrack - pretty sure they both work with joysticks.

It's a really nice joystick and quite sought after so a nice bonus.
by RobC
Fri Feb 09, 2018 7:49 am
Forum: hardware
Topic: Kempston Competition Pro
Replies: 12
Views: 255

Re: Kempston Competition Pro

Not seen a user port version before of that before. I have an identical looking joystick but it plugs into the analogue port. It works well with most games that support joysticks apart from those that require analogue/proportional movement (like Elite & Revs). Unfortunately, I don't know any gam...
by RobC
Thu Feb 08, 2018 3:31 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

and then it hangs. That's probably because ADFS is looking to boot from a disk. Try doing Escape-Break [*] and then setting the configuration options as described in the manual (or the link above). [*] I think Escape-Break will get you out of ADFS but I'm not near enough to my Master to try it out!
by RobC
Thu Feb 08, 2018 2:46 pm
Forum: software: classic games
Topic: Does it exists a version of "Death race" for the beeb?
Replies: 6
Views: 441

Re: Does it exists a version of "Death race" for the beeb?

There's a BASIC version for the Spectrum in this book:
http://www.worldofspectrum.org/infoseekid.cgi?id=2000146

I played it on SpectROM earlier and it's pretty terrible but I can extract the source if you like.
by RobC
Wed Feb 07, 2018 10:18 pm
Forum: wanted
Topic: Risc PC or RPC bits
Replies: 20
Views: 383

Re: Risc PC or RPC bits

If the main sticking point with the Pi is the lack of a MIDI interface, it may be worth reading through this thread: https://www.riscosopen.org/forum/forums/11/topics/1651 There's a (WiP) module that implements the RISC OS MIDI API through a USB interface. I've thought about trying it out a few time...
by RobC
Wed Feb 07, 2018 5:10 pm
Forum: projects
Topic: Going great guns on a Prince of Persia port...
Replies: 197
Views: 13814

Re: Going great guns on a Prince of Persia port...

daveejhitchins wrote:The MK II will have just such a block available :D

Sounds good. I was just wondering whether having lots of ROM available was good enough (as that's what the existing MGC provides)?
by RobC
Wed Feb 07, 2018 2:29 pm
Forum: hardware
Topic: Minimal Tube 6502decode bus snoop with FTDI USB
Replies: 30
Views: 889

Re: Minimal Tube 6502decode bus snoop with FTDI USB

I'd like a board and CPLD too please!