Spectrum Computing

The biggest problem is the 'classic' vs 'newlib' situation. Half the libraries, tutorials, documentation, forums posts etc. are for classic and the other half are for newlib. Each library has its pros and cons but newlib is officially a dead end. Or at least semi-officially to add to the confusion....

Timmy wrote: ↑Fri May 17, 2024 9:54 am Building takes a bit of time but shouldn't be 25 minutes?

Building z88dk on my old (around 12 years old) desktop takes about 15 minutes. I could believe it takes 25 minutes on a modest laptop. But you only have to do it once in a while.

Put the math library link flag at the end of the line:

In the last set of tests, the ULA is not fitted, hence there is no AC signal, the circuit is only operating in a static / DC state. This is primarily to confirm that in a static state it is working okay. It's much easier to pick up basic faults in a static state. Oh yes, of course, that's why the U...

Sorry to stick by rather uninformed oar in again, but... Are you not measuring variable voltages (i.e. AC) with a digital multimeter and trying to interpret the results as DC? If I have, say, a 3.5MHz clock signal, which swings from 0V to +5V on a duty cycle of 50%, what would I expect to see if if ...

I've got a couple of traces from an issue 3 for comparison. This is from pin 32 of the ULA: https://i.ibb.co/wCcxxD9/NewFile2.png The waveform is the same as yours, which is good because it means your ULA is working. Or at least I think it does. I don't know how to read your 'scope's output. It look...

Sweevo wrote: ↑Mon May 13, 2024 12:14 pm I am using Linux Mint 21.3 Cinnamon.

Are you using X or Wayland?

It's odd that an application like Fuse is disturbing your system's graphics settings. That really shouldn't be possible.

Sweevo wrote: ↑Mon May 13, 2024 11:43 am Can anyone recommend a Spectrum emulator for Linux that does fullscreen, doesn't mess with the desktop resolution and is fully working (i.e. keyboard fully works etc).

What Linux distro (and version) are you using? What version of Fuse have you tried?

You do need to tell us how you're observing the clock signal and the waveforms around the transistor. If you have an oscilloscope do you know how to capture images from it so you can upload them?

Don't connect the ULA directly to the CPU. That's not a good idea. You said "cpu clock on pin 6 is incorrect". What do you mean, "incorrect"? Stuck high? Stuck low? Erratic level? Valid signal but at the wrong speed? Give us some details to work with! Also, what test equipment ar...

Given Manic Miner's copyright is disputable (if I'm reading joefish's comment correctly) I humbly suggest MM should be made available again. If they (SP) truly care about it they will need to submit a takedown request with legal proof etc. A takedown request is one option they might pursue. Another...

But then there's this, about Manic Miner : <snip!> I read that a few times, trying to understand why the author wasn't just dismissing their own argument. I was rather baffled by it, but I think I eventually understood the point being made. The ultimate point being made is that Software Projects ow...

It looks like someone got those trademarks, too.

But the Jet Set Willy one has the wrong sprite.

What's sad about that document is it's written by a paralegal. Not a solicitor. It carries no weight whatsoever. Look it up. It wouldn't carry any weight if it had been written by a solicitor either. Until a judge rules on it, it's just people saying what they think, making claims and counterclaims...

Can't remember (or no one knows?) if it was a bug or deliberate that the tune got progressively worse the more lives you lost (I think one of the delay times for the notes was linked to the number of lives remaining). It was a feature! It's in the disassembly, here . Because I always played with in...

FWIW I was a student in Southampton and liked it very much. I still live a bit (well, quite a bit) up the road from there.

pollito wrote: ↑Thu May 02, 2024 4:41 pm So sorry that our engineer mixed up the order number, there is no issue about the order.

Very odd for JLCPCB to mess up like that, they're normally flawless in my experience. Put it down to an aberration at their end.

To complete the story, in case anyone finds it in a search, I got the DC circuit working. I desoldered the cluster of components, then rejoined them all spread out so I could get access to those underneath. I then printed out the circuit shown here , and went through it point by point, ticking off e...

Redgatemodels wrote: ↑Sun Apr 21, 2024 10:16 am Hi, I guess this is a rookie question, but I am trying to get Jetpac onto microdrive and have failed.

Can it be done?

There's a remarkably in depth discussion of this exact question from about a year ago here.

+3code wrote: ↑Fri Apr 19, 2024 7:17 pm Sad. Somehow, I feel the calendar is running out of pages.

For all the tongue in cheek comments others have posted, sadness is my overwhelming emotion too.

Z80s have been part of the computing landscape for about as long as I have.

I know it's hard to tell, but if TR4 is getting hot, one of the 4116 (or equivalent) "lower" DRAM chips may have failed and is now drawing excessive current. Hence dragging the +12V rail down. I'll have a closer look at your photo later when I'm on a PC. This is the current working versio...

The website/blog you linked to is mine BTW. Yes, I thought so. Thanks for doing that. I wanted to tell you that the schematic has two D15 diodes on it, which has rather puzzled me. I think one of them is actually the new D17 which is one of my green dotted diodes in my image? I was also a bit puzzl...

That's an excellent video, but his final work doesn't look much like the board I have!

I'm still working on it...

I have an issue 3 board which has a faulty 12V supply (reads a wobbly +1.2V). -5V works correctly. I've never tried to fix a DC-DC problem before, so I thought I'd start from first principles. The board has had a DC-DC mod of some sort, so I've had a good look at it and taken notes. Here's an annota...

Oh, and during the RAM check that the ROM does, it may be possible to check for some RAM faults that the ROM code does not test for. It's not possible to pick up all RAM faults, because the intention of the ROM routine is to simply work out how much RAM is fitted, NOT if it works correctly. Hence t...