Search found 1107 matches

by Coeus
Tue Dec 11, 2018 1:26 am
Forum: general
Topic: Morecambe & Wise restored using BBC BASIC!
Replies: 14
Views: 321

Re: Morecambe & Wise restored using BBC BASIC!

I recently got round to watching the new WW1 film "They shall not grow old" which is impressive but ultimately, distracting because the eye is drawn to the errors in colour choice and the loss of detail in the images due to the photoshop smoothing that is inherent in the process. Faces appear way t...
by Coeus
Mon Dec 10, 2018 11:29 pm
Forum: off-topic
Topic: Scanning
Replies: 6
Views: 109

Re: Scanning

flaxcottage wrote:
Mon Dec 10, 2018 10:36 pm
In addition to the music I find a good Malt makes the scanning fly by. Mind you the last few pages need a bit of editing to get them square. :lol:
I can see that would help.
by Coeus
Mon Dec 10, 2018 11:28 pm
Forum: off-topic
Topic: Scanning
Replies: 6
Views: 109

Re: Scanning

Now, unless I'm doing something wrong (quite possible), I fed in a magazine from 1984 that had had its spine very carefully removed, told the software to get started, and then sat back expectantly, but after the first side was scanned the machine seemed to sit for a while and then threw up an error...
by Coeus
Mon Dec 10, 2018 7:14 pm
Forum: off-topic
Topic: Scanning
Replies: 6
Views: 109

Scanning

I am sure i have read comments on here about people struggling to put up with the boredom of scanning large manuals etc. I had a go at the Epson FX manual yesterday and did pretty much the same as with the BCPL manual such that you could, perhaps, call it a process or formula. Firstly, I choose a ti...
by Coeus
Sun Dec 09, 2018 11:24 pm
Forum: emulators
Topic: Printer Emulation..(ie ESC P printer emulation)
Replies: 32
Views: 1043

Re: Printer Emulation..(ie ESC P printer emulation)

I have just discovered I have a copy of the Epson FX Printer Operation Manual in my loft so I have fetched it down. In Appendix F the dot patters for the various characters are shown including variations for several languages.
by Coeus
Sun Dec 09, 2018 9:31 pm
Forum: software: other
Topic: Bootstrapping a CP/M installation
Replies: 6
Views: 196

Re: Bootstrapping a CP/M installation

Richard Russell's Z80 BBC Basic can read files from the current Acorn filing system over the tube as well as from the CP/M filing system and there is a program on what I think is the standard CP/M disc one called READDFS.BBC which takes advantage of this to transfer between CP/M and Acorn FS.
by Coeus
Tue Dec 04, 2018 11:14 pm
Forum: emulators
Topic: More interesting 6522 VIA emulation discrepancies
Replies: 28
Views: 502

Re: More interesting 6522 VIA emulation discrepancies

Thank you Ed! Results are consistent with the original run, so I didn't screw up. So the VIA doesn't acknowledge the IRQ if a load/store happens in the same cycle that it's generated. We can probably theorise all sorts of reasons why this might be the case, but as far as emulating it goes, it's a c...
by Coeus
Tue Dec 04, 2018 4:04 pm
Forum: software & utilities for the pc, mac or unix
Topic: Matrix Brandy BASIC V for Linux with SDL: V1.21.17 released
Replies: 425
Views: 14447

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

I can build and test Matrix Brandy Basic builds for MinGW/SDL, MinGW, DJPP and RISC OS, but don't have a unix build environment. I can dual boot my PC into Puppy Linux. Can anybody recommend a suitable C compiler to build Brandy? I am not sure commerical C compilers have ever taken off for Linux. g...
by Coeus
Mon Dec 03, 2018 2:15 pm
Forum: emulators
Topic: More interesting 6522 VIA emulation discrepancies
Replies: 28
Views: 502

Re: More interesting 6522 VIA emulation discrepancies

- b-em, b2, jsbeeb shouldn't be adding one to the T2 counter when in pulse counting mode. I can see that this is an improvement in that, from a software perspective, the 6522 emulation looks correct, and it should be easy to add a test for pulse count mode and not add the 1. I am not convinced it m...
by Coeus
Sat Dec 01, 2018 1:04 pm
Forum: emulators
Topic: Testing for deterministic NMI timing
Replies: 12
Views: 251

Re: Testing for deterministic NMI timing

The NMI signal then stays asserted, and that changes the timing on subsequent runs, making the test not very repeatable. According to the 1770 data sheet the INTRQ line, which I assume is the one being asserted here, is reset by reading the status register. Is the timing consistent after doing that?
by Coeus
Sat Dec 01, 2018 12:59 pm
Forum: emulators
Topic: Testing for deterministic NMI timing
Replies: 12
Views: 251

Re: Testing for deterministic NMI timing

Also, both b-em and jsbeeb (which copies the FEslowdown table verbatim) consider 0xFE20 - 0xFE3F and 0xFE80 - 0xFE9F 2Mhz accesses regardless of whether there's an i8271 or wd1770 present. Could be that's corrent for i8271 but not wd1770. Although I had not noticed that clock being stretched out to...
by Coeus
Sat Dec 01, 2018 12:21 am
Forum: emulators
Topic: Testing for deterministic NMI timing
Replies: 12
Views: 251

Re: Testing for deterministic NMI timing

Much more promising, has a dedicated command 0x0D to force an NMI immediately! Would love to confirm this in action on a real wd1770-equipped beeb as well as confirming the timing of this event. The name of the command does tend to suggest its purpose is to generate an interrupt but the data sheet ...
by Coeus
Thu Nov 29, 2018 2:06 am
Forum: emulators
Topic: Default sn76489 sound chip state
Replies: 13
Views: 263

Re: Default sn76489 sound chip state

So it is ... I knew there was something different about it! Look at the startup message as embedded in OS 1.20 - the addresses are file offsets so this is actually at C300: 00000300 - 4C 1D CB 0D 42 42 43 20 43 6F 6D 70 75 74 65 72 L...BBC Computer 00000310 - 20 00 31 36 4B 07 00 33 32 4B 07 00 08 ...
by Coeus
Tue Nov 27, 2018 7:33 pm
Forum: hardware
Topic: Need help with BBC just picked up please
Replies: 169
Views: 3017

Re: Need help with BBC just picked up please

At this point it would be good to understand what makes PCB tracks lift off and how to make sure more of the same does not happen in the attempt to repair the ones that have already lifted. Can one of the more experienced hardware guys offer some insight here?
by Coeus
Tue Nov 27, 2018 6:27 pm
Forum: emulators
Topic: Can someone try some simple 6522 VIA queries for me on a real BBC?
Replies: 34
Views: 562

Re: Can someone try some simple 6522 VIA queries for me on a real BBC?

I have just thought of another subtlety that I think B-Em may get wrong, though, which is that in latching mode the mixing of the input/output values as per the DDR should happen at latching time, not at reading time.
by Coeus
Tue Nov 27, 2018 6:08 pm
Forum: emulators
Topic: Can someone try some simple 6522 VIA queries for me on a real BBC?
Replies: 34
Views: 562

Re: Can someone try some simple 6522 VIA queries for me on a real BBC?

Maybe Rich means the thing whereby when you read port A you get pin values or latched pin values (and DDRA plays no role - it's controlled entirely by latching enable/disable), and when you read pin B you get pin values (for output bits) or ORB/latched pin values (for input bits). For most normal c...
by Coeus
Tue Nov 27, 2018 4:15 pm
Forum: hardware
Topic: Need help with BBC just picked up please
Replies: 169
Views: 3017

Re: Need help with BBC just picked up please

My conclusion that bit 7 is stuck high, not low came from the fact that the colour coding in the Frogger screen is OK, which uses teletext codes with bit 7 set? But I could well be wrong, not an expert on teletext codes. Teletext, at least of that era, is 7 bit. With bit 7 as zero, these codes woul...
by Coeus
Tue Nov 27, 2018 1:56 pm
Forum: emulators
Topic: Can someone try some simple 6522 VIA queries for me on a real BBC?
Replies: 34
Views: 562

Re: Can someone try some simple 6522 VIA queries for me on a real BBC?

Oh, I am vaguely terrified of the 6845, not sure how strongly I'll bat for accuracy there. In terms of what's observable to 6502 code, most of the 6845 is read-only. If we discount the light pen feedback, the main (only?) observable is the vsync interrupt timing. Also memory address generation and ...
by Coeus
Tue Nov 27, 2018 1:50 pm
Forum: emulators
Topic: Can someone try some simple 6522 VIA queries for me on a real BBC?
Replies: 34
Views: 562

Re: Can someone try some simple 6522 VIA queries for me on a real BBC?

...b2 also suffered from the T1 issue, but it did sort-of do the right thing provided DDRB bit 7 was always an input, so Snapper-V1 happened to work, by accident, in most cases. Now fixed. Interesting. My understanding of the test case from earlier in the thread running on a real machine is that th...
by Coeus
Mon Nov 26, 2018 5:30 pm
Forum: hardware
Topic: Need help with BBC just picked up please
Replies: 169
Views: 3017

Re: Need help with BBC just picked up please

so thats not viable any other ideas please I would like to save this one from the scrap heap Please don't scrap it whatever you do. Hoglet's "Bring it to ABUG" suggestion is a good one. At the one ABUG meeting I have been to there was an impressive range of test equipment and expert guys who enjoye...
by Coeus
Mon Nov 26, 2018 2:07 pm
Forum: emulators
Topic: Can someone try some simple 6522 VIA queries for me on a real BBC?
Replies: 34
Views: 562

Re: Can someone try some simple 6522 VIA queries for me on a real BBC?

el! So now we all know how 6522 VIAs behave in this instance, and how to get Snapper to work properly. Also, MAME gets some form of trophy for having better 6522 emulation than the dedicated BBC emulators. That is no surprise to me. MAME takes the approach of trying to emulate individual components...
by Coeus
Sun Nov 25, 2018 12:45 pm
Forum: software: other
Topic: Midi to Ample Converter
Replies: 10
Views: 359

Re: Midi to Ample Converter

Can Studio 5000 record the Music 4000 to AMPLE? If so, on Linux at least, you use the OS MIDI features to play the MIDI file into B-Em on the MIDI port that emulates the Music 4000. Unfortunately that would not keep velocity/aftertouch info. I don't think you can do it with ALSA RAW but ALSA SEQ and...
by Coeus
Sat Nov 24, 2018 5:55 pm
Forum: general
Topic: British Micro Federation
Replies: 35
Views: 753

Re: British Micro Federation

Looks a pretty disturbing development to me. Just with games, you don't just have a download and that's it, until the hard disk knackers. Some git with a mouse decides how long or often you access it. Welcome to the monopoly granted by copyright. In the case of the Amazon example, what you're also ...
by Coeus
Wed Nov 21, 2018 5:51 pm
Forum: hardware
Topic: Need help with BBC just picked up please
Replies: 169
Views: 3017

Re: Need help with BBC just picked up please

Test rom is 27c2560 It was a 27C256 (32K) containing two identical copies of the 16K test ROM. Dave So if the most significant address line (A14) was not reaching the test EPROM correctly it would still work as it would read the same code if it was high or low. The same would not be true of the OS ...
by Coeus
Mon Nov 19, 2018 10:20 pm
Forum: hardware
Topic: Cracking tinnitus, Gromit
Replies: 10
Views: 439

Re: Cracking tinnitus, Gromit

I haven't watched the video you attatched yet (problem is at my end) but when you say it beeps, is that a continuous beep or the expected boo-bip? from watching the video, the sound is the first one only, i.e. the one due to the sound chip not having been initialised yet. The ^G clean-sounding beep...
by Coeus
Mon Nov 19, 2018 9:27 pm
Forum: software: other
Topic: Updated BASIC Editor
Replies: 46
Views: 3528

Re: Updated BASIC Editor

...and then used *SRLOAD BASICED 8000 4 but that results in a Channel error... Is the file too big? I wonder if it is overwriting the filing system workspace and thus causing the channel error. The filing system workspace would be low on a BBC B but on a master I believe it is in some RAM that is p...
by Coeus
Sat Nov 17, 2018 6:09 pm
Forum: software: other
Topic: Searching for an old demo
Replies: 4
Views: 230

Re: Searching for an old demo

Not all music was rubbish on the beeb. Take for instance this great catchy tune called Melvyn Wright's Music Machine (or simply Beebioli): www.youtube.com/watch?v=GNiiBc6bjnU That has more than passing similarity with "Liberty Bell" by Sousa, well known as the Monty Python theme tube. I'm not sure ...
by Coeus
Thu Nov 15, 2018 4:55 pm
Forum: general
Topic: How much of this is just rose-tinted specs?
Replies: 21
Views: 580

Re: How much of this is just rose-tinted specs?

When we think we see times changing it might just be perspective... That's an interesting point and sometimes it is hard to be sure which is which. As an example, I knew how the internal combustion engine worked before I went to primary school because I had seen it explained on TV. The fact there w...
by Coeus
Tue Nov 13, 2018 11:01 pm
Forum: software: other
Topic: First third party DFS ?
Replies: 20
Views: 688

Re: First third party DFS ?

^STL issue1, as can see on board pins, there is only 1 bit logic #-o hence pants. Ok, so I have dug out the circuit diagram for the issue 1 board: http://www.adsb.co.uk/bbc/disk_controllers/ddfs_v1.jpg I think what you are talking about is this little bit of the circuit: latch.png Where they have c...