Search found 1963 matches

by BigEd
Tue Aug 14, 2018 5:15 pm
Forum: hardware
Topic: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male
Replies: 10
Views: 176

Re: Raspberry Pi B+ compatible GPIO Extender 40-way Ribbon Cable Female-Male

The Master is, for this purpose, a much more solid design than the Beeb. The Tube bus is more or less private to the things you connect to it, and so it can tolerate a long cable. The Beeb is much less solid. Everything you add on the inside or outside adds to the load on an already overloaded inter...
by BigEd
Tue Aug 14, 2018 9:30 am
Forum: general
Topic: BBC releases computer history archive
Replies: 112
Views: 2511

Re: BBC releases computer history archive

... how pervasive wifi would become. You can nearly get away without data service... How smoothly do you find that working? Just about well enough, with the exception of when I use the phone as a satnav. There are quite a few components to the attractiveness of a modern smart phone, and I'm not sur...
by BigEd
Mon Aug 13, 2018 9:08 pm
Forum: general
Topic: BBC releases computer history archive
Replies: 112
Views: 2511

Re: BBC releases computer history archive

Indeed, touch came out second. I do wonder though if it might have been developed first. There's a lot of cleverness in the on screen keyboard, disambiguating big fat fingerpresses. Something which perhaps wasn't quite clear at that time is how pervasive wifi would become. You can nearly get away wi...
by BigEd
Mon Aug 13, 2018 4:57 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

I'm intrigued - what's the idea? Easy enough if the z80 has something between itself and the socket?
by BigEd
Wed Aug 08, 2018 8:07 pm
Forum: acorn atom
Topic: Building an Acorn System 1
Replies: 13
Views: 461

Re: Building an Acorn System 1

(Hello world dates from at least 1972!)
by BigEd
Wed Aug 08, 2018 11:38 am
Forum: acorn atom
Topic: Building an Acorn System 1
Replies: 13
Views: 461

Re: Building an Acorn System 1

Great result!
by BigEd
Tue Aug 07, 2018 7:20 pm
Forum: software
Topic: Unix for Archimedes
Replies: 21
Views: 461

Re: Unix for Archimedes

A bit later than that, I've just found the R140 from 1989 with a floating point coprocessor (at least as an option?) Acorn introduced the WE32206 Floating Point Co-Processor at the same time as the R140 Unix Workstation. http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_AKA20_WE3220...
by BigEd
Tue Aug 07, 2018 7:14 pm
Forum: software
Topic: Unix for Archimedes
Replies: 21
Views: 461

Re: Unix for Archimedes

Looks like the Archimedes with ARM3 had a socket for a floating point coprocessor, the FPA10 or later FPA11 , both from 1993: In July 1993 Acorn finally released the FPA10 Floating Point Accelerator for the A540, A5000 and R260 which boosted floating point performance by a factor of 50. The Acorn A...
by BigEd
Tue Aug 07, 2018 6:22 pm
Forum: upcoming and recent events & exhibitions
Topic: Vintage Computer Fest - Mountain View, California - Aug 4-5
Replies: 3
Views: 181

Re: Vintage Computer Fest - Mountain View, California - Aug 4-5

myelin wrote:
Tue Aug 07, 2018 6:13 pm
A few pics from this event, on the FB group.
Hmm seems to be a closed group - any chance you could liberate these photos?
by BigEd
Tue Aug 07, 2018 3:15 pm
Forum: development tools
Topic: Deploy-and-run from PC to Beeb?
Replies: 26
Views: 459

Re: Deploy-and-run from PC to Beeb?

I think I've used PerlHost, on Linux, and I'm pretty sure hoglet has too. (It's been a while.)

Edit: reference http://mdfs.net/Software/Tube/Serial/ because I keep getting confused about host software vs client software.
by BigEd
Tue Aug 07, 2018 8:34 am
Forum: hardware
Topic: Acorn Sales Figures of Model A/B
Replies: 4
Views: 254

Re: Acorn Sales Figures of Model A/B

Some tiny hints in the booklet "Towards Computer Literacy" : Meanwhile the Model A had been chosen by the Department of Industry as one of two micros which qualified for 50% government funding for use in secondary schools, and many schools were keenly awaiting their machines. Early reviews of pre-pro...
by BigEd
Tue Aug 07, 2018 7:17 am
Forum: hardware
Topic: Acorn Sales Figures of Model A/B
Replies: 4
Views: 254

Re: Acorn Sales Figures of Model A/B

I'm pretty sure I've read that Acorn and the BBC expected the bulk of sales to be the Model A, and so they produced too many Model A. Some unsold Model A were then upgraded before sale to Model B. But I can't find any reference for this. It might be that one can spot a factory-upgraded machine like ...
by BigEd
Mon Aug 06, 2018 8:08 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

Just for completeness: mine's an SGS Z8400BB1 Z80B CPU (6MHz) datecode 88346
by BigEd
Mon Aug 06, 2018 7:58 pm
Forum: development tools
Topic: Deploy-and-run from PC to Beeb?
Replies: 26
Views: 459

Re: Deploy-and-run from PC to Beeb?

I suppose this is the link for UPURS:
https://www.retro-kit.co.uk/UPURS/
by BigEd
Mon Aug 06, 2018 6:51 pm
Forum: software: other
Topic: cc65 C Cross Compiler
Replies: 22
Views: 1916

Re: cc65 C Cross Compiler

Do you have a repo which is easy to pick up from?
by BigEd
Mon Aug 06, 2018 6:44 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

hoglet wrote:
Mon Aug 06, 2018 6:24 pm
Ed,

What flavour of Z80 does your Z80 Second Processor contain?

Dave
Ah, good question. It turns out to be an SGS. The label is rather unclear, but that much is certain.
by BigEd
Mon Aug 06, 2018 6:03 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

Richard Russell wrote:
Mon Aug 06, 2018 5:48 pm
BigEd wrote:
Mon Aug 06, 2018 4:32 pm
60 LD A, &38 :\ value to be copied
The semicolon comment delimiter, as listed by the OP, is accepted by BBC BASIC (Z80) isn't it?
Yes, it is. I'd meandered my way to an acceptable syntax, and not found the optimum route.
by BigEd
Mon Aug 06, 2018 4:32 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

Mutatis mutandis, as we used to say: >L. 10 DIM code &100 :REM reserve some code space 20 DIM data1 &100 :REM reserve some data space to read from 30 DIM data2 &100 :REM reserve some data space to write to 40 P%=code 50 [OPT 0 60 LD A, &38 :\ value to be copied 70 LD (data1), A :\ store this in data...
by BigEd
Mon Aug 06, 2018 12:51 pm
Forum: hardware
Topic: Acorn Sales Figures of Model A/B
Replies: 4
Views: 254

Re: Acorn Sales Figures of Model A/B

This thread doesn't answer your exact question, but it's related:
by BigEd
Mon Aug 06, 2018 10:05 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

The answer may be here - the only path to read IR is through an incrementer: Perfect, that explains it. Sorry, I was quite wrong! The extra increment is caused by the ED prefix - LD A, R is a prefixed instruction. The prefix gives you an extra M1 cycle, apparently. Did you also see this : NEW From ...
by BigEd
Mon Aug 06, 2018 9:15 am
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

There might well be a difference between power on and a subsequent reset: I think Ken Shirriff found that the bits which decide which of the register sets is the current one and which is the alternate are not initialised.
by BigEd
Mon Aug 06, 2018 9:13 am
Forum: development tools
Topic: Deploy-and-run from PC to Beeb?
Replies: 26
Views: 459

Re: Deploy-and-run from PC to Beeb?

I have been known to paste smallish programs over the RS423 serial port, but UPURS is a much faster and more convenient interface: it's a simple cable, and a ROM.
by BigEd
Mon Aug 06, 2018 6:42 am
Forum: programming
Topic: Beeb SOUND weirdness
Replies: 7
Views: 183

Re: Beeb SOUND weirdness

Good digging! (I tried to find where I'd got the info from, and failed.)

I think this finding reinforces the idea that this kind of sound chip isn't especially musical, and hints at why Bob Yannes was able to do better, with the SID.
by BigEd
Sun Aug 05, 2018 8:35 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

The answer may be here - the only path[1] to read IR is through an incrementer: http://static.righto.com/images/z80/Z80_arch.svg-w700.png See also, perhaps, The Z-80's 16-bit increment/decrement circuit reverse engineered and generally Ken's Z80 reverse-engineering series . [1] Edit: Oh hang on, tha...
by BigEd
Sun Aug 05, 2018 7:56 pm
Forum: software
Topic: Unix for Archimedes
Replies: 21
Views: 461

Re: Unix for Archimedes

Ooh, nice thread! I see there that it's Jules Richardson who has some ARX source code.
by BigEd
Sun Aug 05, 2018 7:40 pm
Forum: software
Topic: Unix for Archimedes
Replies: 21
Views: 461

Notes on ARX, not a Unix

Have to admit that I'd forgotten about ARX :oops: Was it Unix like? That's a good question: I think probably not, on the inside. Certainly not derived from Unix. In terms of capabilities, perhaps somewhat: multi user, multi process, pre-emptive. But I'm not sure any ARX materials survive - no wait,...
by BigEd
Sun Aug 05, 2018 6:14 pm
Forum: programming
Topic: Beeb SOUND weirdness
Replies: 7
Views: 183

Re: Beeb SOUND weirdness

I think I read recently in another thread that the MOS detunes one note if you play the same pitch on different channels, so you get a fatter sound. JSBeeb is doing the same thing as the others, I think.
by BigEd
Sun Aug 05, 2018 5:34 pm
Forum: software
Topic: Unix for Archimedes
Replies: 21
Views: 461

Re: Unix for Archimedes

That's good to know Rob... but let's not forget the unreleased ARX which was what Acorn intended to use, but which wasn't looking likely to finish in time (or at all), and so ARTHUR was born. ARX was an unreleased Mach-like operating system written in Modula-2+ developed by Acorn in the UK, and late...
by BigEd
Sun Aug 05, 2018 5:00 pm
Forum: hardware
Topic: Z80 Protocol Decoder
Replies: 114
Views: 1612

Re: Z80 Protocol Decoder

Hmm, I did a second load:

Code: Select all

LD R, A
LD A, R
LD A, R
and the result is A gets A+4