Rick's b.log - entry 2023/01/22

Electron

I note on eBay the prices are all over the place, but "about eighty quid" for one (buy it now). That's the British eBay. There are none on the French eBay (except a complete kit over €200) because nobody wants to deal with the crappy postage and customs formalities.

That's why I'm not going to be sending mine to VinceH. I have no problem with doing so, I mean, it's not as if I have ever used it. But international... god's sake. Call it yet another Brexit Bonus.

Anyway, it's the baby brother to the venerable BBC Micro.

Acorn Electron.

You can see there are none of the infamous red function keys. They are duplicated by pressing the FUNC key (under ESCAPE) and one of the regular numbers.
Actually, that FUNC key is a busy little thing. Do you see all those BASIC keywords printed on the fronts of the keys? Pressing FUNC and Z and then FUNC and X would cause ENDPROC to appear (as END and then PROC).
However unlike the Spectrum this was not forced. You could write it out if you preferred.

Speaking of the Spectrum, Acorn were worried that the infamously rubbish but much cheaper Spectrum was selling bucketloads and this was a problem for Acorn. Obviously, the vastly superior Beeb offered many facilities that were irrelevant to many home users. Space for an Econet interface? Tube? 1MHz bus? Provision for a speech synthesis.
So they created the Electron, codenamed Elk, which took the 100-odd chips in the Beeb to a much smaller (and cheaper) 15 or so.

Offering 32K or RAM and 32K of ROM, it behaved akin to a model B. And, one must say, it had a simple but lovely design. A simple creamy-beige box that didn't scream "look at me". Just precisely understated.

So it arrived in the lower price band - £199 at launch, with a very nice keyboard compared to its contemporaries (the Oric-1 must surely stand out as a keyboard from hell) as well as better graphics capabilities than the others.
It wasn't, however, perfect. It did have a number of important limitations compared to the Beeb; and after a while the price was reduced to £129. Alas, it wasn't plain sailing for Acorn as the 80s home computer market imploded causing losses and a deal with Olivetti to prop up Acorn.
That being said, Acorn tried again shortly after with the Master Compact, and in the Archimedes era, with the A3000; and later on with the A30x0 range.

While Acorn may have lost interest in the Electron, it's low price shifted many units so third party companies made many add-ons.

The other part of the puzzle is the wall wart or power brick. Brick is an appropriate word. Anyway, it's the baby brother to the venerable BBC Micro.

Power brick.

The PSU is inside the Electron itself. What this lump is, is a big transformer to drop the mains down to 17-20V AC, which is what the Electron accepts as a power supply.

So, wang it into the composite to VGA adaptor and the wall wart and...

A quick program.

That power lead is the one to the composite to VGA adaptor. I've just taken a photo of the screen.

Running the program does this, as expected.

It actually works!

Well, not quite. There is no colour. I whipped out my soldering iron and dragged a blog of solder to short out LK4 (in the middle of the bottom left quadrant) to add the colour carrier, however this upset the VGA adaptor which pushed the left margin of the video over to the right hand side of the screen, so I undid this. It'll just have to be monochrome. I suspect analogue equipment might have been more forgiving... but I don't have anything to try it on, not any more.

Since I had the thing open, we can peek inside. It's a marvel of miniaturisation compared to the BBC Micro.

Electron motherboard (issue 4).

It's basically split into five sections. The left third of the board is the audio and video circuity. A whole plug at the top goes to a speaker, and the line of pins in the middle of all of this is the keyboard connector.

The next section is the two ROMs at the top. This was originally a 16K MOS ROM and a 16K BASIC ROM, however for release models these were combined in a single 32K ROM and the holder on the left is unused (and is removed completely in later models).

The long chip is the 6502 processor. It's a generic 6502A. You'll need to wait for the Master before the 65C02 or 65C102 come into the question. It is, however, the Synertek version of the processor as this one can support stopping the system clock.

Along the bottom right, four RAM chips of 8K each, offering 32K in total. However, it is four 64Kbit (8KB) devices arranged to provide four bits at a time. This means that every byte requires two memory reads. The ULA handles this, however between this and the video memory sharing the memory bandwidth, the processor runs at 1MHz (rather than the usual 2MHz) when accessing RAM; and in high resolution/colour screen modes (0-3) there is not enough bandwidth to support interleaved access to the processor and video system, to the processor is actually stopped as data for the active part of the display is read out of memory; that is to say, in a 64µS period, the video system will claim 40µS to read out the pixel data, and the processor will run for the remaining 24µS (the flyback time).
Plus some logic for decoding.

Which leaves that huge 68 pin ULA.

The ULA.

The Electron has RAM, ROM, some video handling, and a CPU. This ULA is the "everything else", an attempt to put a Beeb into a chip. It provides incomplete clones of the various bits of hardware inside a Beeb, such as:

• Audio generator (but onhly one channel at a time, and amplitude can't be varied)
• CRTC (but it's not as customisable)
• Video ULA (but it shares memory timing with the CPU so the processor runs at half speed when accessing RAM)
• Serial hardware and serial ULA (for the tape interface, there's no serial port and 300 baud isn't supported).
• Keyboard interface (it's a weird system where data signals sent appear on the address bus (it is mapped in as ROMs 8 and 9, or addresses &9FFF to &BFFE); so there's no 6522 in here).
• ...which means the 6522 timers aren't available.
• System timing for video sync, memory refresah, etc.

There's also no MODE 7.

Because of this reduction of facilities, you have the following friendly I/O ports.

I/O ports.

UHF TV output, normally channel 36.
Composite video, normally monochrome.
TTL RGB output (either on or off, not analogue).
And finally the tape interface (with start/stop control) using standard CUTS tones and a 1200 baud data rate, but an Acorn specific block header (so rewind/retry works).

Around back there's an interface for other things, and the Plus series of adaptors have added on things like 3.5" floppy drives.

Expansion port.

It is segmented into two parts. I think the smaller part is all the various power lines (including the 19VAC directly from the transformer!) as well as data, address, control, and timing signals.
But like the Spectrum, it's a PCB edge connector that positively invites having random stuff short it out. This probably should have been hidden behind a sprung flap or something...
While the many ports bristling underneath the BBC Micro offered a rather limited access to the internal address and data bus, the Electron's expansion bus offers the complete internal bus for ease of adding things to the machine.

The smaller part on the right carries the entire address bus as well as 0V and +5V on the far right. The larger part carries the entire data bus (right), timing and control signals (middle), and power (18VAC, +5V, 0V, -5V; left).

Here's the power supply.

Power supply.

The power supply outputs +5V (1.5A) and -5V (100mA, used by the cassette interface).

Overall, it was fairly crippled compared to a BBC Micro. However it was quite popular, especially with the Plus 3 expansion which brought the more durable 3.5" floppies along with ADFS, making it at one point the best selling home computer in the UK.

Tory tax

Gardening

The 'before' picture.

I did the right hand half at the end of last year, after having cut it back in March 2021. It's ridiculous/depressing how quickly the trees regrew. I'll have to keep them down so they - hopefully - get the message.

Anyway, a little bit of work later and...

The 'after' picture.

I also tied up the downpipe in its place. It hasn't really been right since the storm in May 2020 broke several of the mountings. I suppose I ought to see if I can get new ones and rig it up better than tying stuff up with bits of the plastic twine that's used to bale hay.

Today? It's quarter past two in the afternoon and just crossed 1°C. It went to -6°C in the early morning (around 9am). Accordingly, I stayed in bed and watched random rubbish on YouTube. I won't be going outside. Oh, and that 14°C anomaly? Won't see those sorts of temperatures until March. Hmmm...

Radio!

Just pop the radio on for a moment or two.

Lower right, how long that station has been playing, and how long the connection has been running for. Yup, uninterrupted for all that time.
The 1/14 is saying that this is channel 1 of 14 remembered as favourites.

I've still not tested the radio's battery life. However I listen to it quite a lot (currently BeGoodRadio for 80s metal) and it works reliably. No glitching, and the internal speaker sounds better than my desktop ones. The UI is simple and to the point.
Just as long as you don't fiddle too much with the order of the favourites (where it gets itself in a twist) or try to stream .m4a AAC (crashes it!), all works nicely. If you treat it as a simple radio, you can basically pick a station and then leave it to get on with playing.

If you want better audio, external speakers and an amplifier are a good idea. With a line out socket, this is easily catered for.

Free electricity!

Chèque energie.

I could send this to EDF, but since this is France, I just went to the government website, gave the number of the cheque and my electricity contract/client numbers and an email address to get the confirmation. Sorted in three minutes.

I have specified to have this done automatically in the future as long as I'm elegible.
There are other associated protections. If I miss paying a bill, they cannot reduce my consumption level during the winter months (I don't think they can turn you off, but the usual response to unpaid bills that escalate is to drop people to 1kW), plus I will ber exhonerated the mass of admin fees that get attached to late/unpaid bills, plus the interest and other penalties.
That being said, I find failure to pay would be... shameful. Plus such things will get noted and could affect things in the future. I understand that some people have a lot more difficulty with paying than me, so this gesture may prove to be a literal lifesaver to some.

I'm lucky. I'm an introvert who grew up in cold bedrooms. I'm heating a little right now (fingers get cold bashing on these keys!) but I suspect most people coming into my home would say "Jesus Christ!" (or some other blasphemy or obscenity) and turn right around. Me? Put a jacket on and make another cup of tea. Of course it's cold, it's winter!

Anyway, cold. Yeah. Single, alone, and perfectly happy to occupy myself by myself, like writing this crap. ☺ Which means that my wage is more than sufficient for the way I live. Oh, and I don't have expensive tastes in food. A lot of pasta, porridge, pasta, and maybe some pasta. Going to Picard (good but pricey) is a luxury. Dropping fast food has helped too. So, yeah, I'm doing okay. But I accept that my way of life is probably alienating to the rest of the world.
I mean, during my meeting with my boss, she pointing out all the positives of integrating with others. So I smiled and said "uh-hu". She. Doesn't. Understand.

Put it like this. My dream is to win the lottery.............and buy an old observatory on top of a mountain, so I can spend the rest of my days admiring the view, during the day and the night. I think, like Wednesday Addams, I tolerate other people. ☺

Anyway. I guess that's my winter bill sorted. Thank you, France.

PS: France - you use a lot of nuclear and the price of gas has come down after Putin's shock was more him shooting himself in the foot than anything else. So why is the company I work for asking us to turn the lights off in empty rooms because the price of electricity is going up 75%? What the hell? That's going to have quite an impact on manufacturing.

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Rick, 22nd January 2023, 15:22

https://twitter.com/VinceMH/status/1616518991664619520

VinceH, 22nd January 2023, 17:06

I paid £49 for the Electron including the P&P.    It's possible I have the original wall wart (I'd forgotten it was one of those; I just remember it being big) from my old Electron. It depends how I got rid of it (if sold/given away, it would have gone with it, but if I skipped the Electron, I might still have it buried somewhere).    However, Andrew Conroy said he has one and (if he remembers) will bring it up to the RISC OS SW show.    Failing either of those options, I don't think it'll be too difficult to find something suitable - I have a lot of these things in various crates etc.

David Pilling, 22nd January 2023, 17:09

My memory of the Electron is that one Christmas (there's an excellent wikipedia page) 1983, people were excited "we're getting an Electron for Christmas", and they didn't, by the next Christmas there were lots of Electrons and no one wanted one.  All the folly of assuming memory would be expensive forever - I gather that 4 bits at a time memory is what delayed matters.    Lots of chat about how French nukes are not running as much as they would hope - lots of maintenance. Prices, they hedge against rises, that's why what you pay does not drop instantly when the spot price falls. Hedging works both ways. Interest will be what happens next year.

David Pilling, 22nd January 2023, 18:39

Have you seen the hotel in an observatory on top of an Alp:  https://www.youtube.com/watch?v=OAf6nFbDMxI    (Switzerland’s Kulmhotel Gornergrat)    When things on the energy front started to get bad, EON handed out free socks to its customers. The politician who suggested people get a woolley jumper and that the cold would be good for them and for the planet would not get far.    For some people being cold is a big risk - might have been cheaper for government to pay for them to go on holiday in the South.

Rick, 22nd January 2023, 18:56

Oh, now THAT place looks interesting.    <looks at booking.com> My god, I'd need a lottery win just to be able to go there!

John, 22nd January 2023, 19:04

We pensioners have had an embarrassment of payments - £400 in 4 instalments, and our winter fuel payment of £250 each IIRC.    People on benefits got a bit more in the instalments bit, but I do pity the poor sods who are actually poor, where the choice between eating and heating is very real!

J.G.Harston, 23rd January 2023, 02:51

Dave Hitchens/RetroHardware still does Electron spares and repairs, as well as new and reimplemented hardware expansions. I've written some of the support firmware. :)  He doesn't have a website, but you can find him on StarDot.

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