Spectrum Computing

Thanks for all the great input, much of it does not make any sense at the moment but I will endeavour to learn more. What I take away is I will leave it as is for now but I must implement some code - and potentially optimise my code - to write to screen following the Rasta scan.

I’ll definitely be coming back to this post once I am ready. Thank you.

ParadigmShifter wrote: ↑Thu Mar 21, 2024 2:43 pm It still shouldn't flicker as long as you are drawing ahead of the raster.

That’s good to know, once I’ve sorted the main game features I’ll look at understanding the Rasta and hope that it smooths the whole thing out.

Most games will draw the game to somewhere else in memory first, with all the scrolling done, sprites added, then copy that to the screen in one go. It's not as fast as drawing straight to screen memory, but it cuts out a lot of flicker. Also you can define your in-memory screen however you want. M...

A question, when you mean "attribute scrolling" you mean 8-pixel scrolling including pixels, and not just attributes, right? In that case n-pixel scrolling won't solve your problem with flicker, because the amount of screen (in bytes) that is being updated has not changed. I am mostly pri...

I’ve taken a long time - some 2 months to develop an attribute scrolling “game engine”. In the centre of the screen is my Sprite, it never moves, it is the screen around it that moves. As you press the “up” key the screen looks for the next line of data and draw direct to screen starting at top left...

And what kind of game are you writing if I may ask? Are you already struggling with little memory left or are you just checking? If memory is a problem then you need to consider some optimisations. No problem as yet. I am just think ahead. The code can definitely be optimised but right now I am jus...

Loading screen shouldn't really be any problem. You load it directly to screen memory while loading and the game later overwrites it. It doesn't occupy any memory when the game is running. Or did you mean something else? A game need some Basic loader. But if you keep it minimal (load loading screen...

I’ve been building a game since January, it’s still chock full of challenges before I get it near to finished. So rather than find out when I’ve nearly finished I would like to get a view from those that know how much memory I will need to leave at the end of the game for loading screens and such li...

I would imagine they are still going strong “… our ten megabyte computer…” future proofed for sure It does make me wonder when did we stop talking about storage and start with CPU speeds?

Ughh, school boy error, should be visible now.

So I have taken this project as far as I intend for now. its been a real mark in the sand for me as I now know I can look to use my Spectrum for a whole host of other projects. I was really surprised at how the components in the books circuit diagrams can still be bought and used some 40 years later...

Hey Mark, All working. :dance excuse my messy work bench! The led lights shows the sensor being triggered, the board additionally sends approx 5v to an output pin which the Spectrum will pick up on via "IN 1". In the book I am working from, the original design for the trigger had the light...

That’s so much good info. Above and beyond Mark but thank you so much. Now all the bits have arrived, I am going to take it slow but hope to have something together by tomorrow.

1024MAK wrote: ↑Tue Feb 13, 2024 4:30 pm I'll get a real one out later and take a photo.

Mark

Thanks Mark, I believe using my multimeter I can identify the base so I will just use that as the reference point and hope for the best.

Thanks Mark, I had a good look and it really helps to have as a reference point. It helped me realise that my previous post was not very clear. The problem I have with the transistor, if you look at the farnell data sheet go clockwise from the emitter and the next leg is the collector whereas on you...

Thanks again Mark, I’ll sit down with a cup of tea and go through all that, at a high level it makes sense. I am waiting on the resistors to arrive so have at least a few hours tomorrow morning before my postie arrives - although I suspect Wednesday is more likely.

Thank you Mark,

So with the base being positive does that mean it is attached to the 1k resistor above it that currently shows the collector?

Beginner Alert !!!! I am a bit confused by the book, and wonder of someone experienced with circuits can help - or confirm there is an inconsistency in the book. The book shows a Transistor BC108 mounted in the circuit yet the names of the legs in the book don't seem to correlate to the Farnell Data...

I presume you mean this I/O board from Tynemouth Software on the Sell My Retro site? Tynemouth Software made a blog post about this I/O board here . Ahhh that’s it… I must have found the blog first then bought the board. Of course that’s where the book came from as well. Thank you Mark. I will take...

PeterJ wrote: ↑Fri Feb 09, 2024 5:26 pm Great little construction project @Hedge1970. Nice work!

Thanks Peter, I suspect I’d have had a different career had I discovered this when I originally got my spectrum.

I discovered the concept of a latch card a couple of years ago after asking about controlling robotic peripherals. The name was new to me, I discovered it along with a shopping list, albeit 40yrs old in Sinclair Projects magazine https://spectrumcomputing.co.uk/magazine/188/Sinclair_Projects . I sta...

@Hedge1970 I'm currently working my way through the Toni Baker book but I'm coding in VS Code, then assembling on my Mac using sjasmplus, then loading the binary file into FUSE emulator and running the machine code using RANDOMIZE USR 30000. So it's a hell of a lot easier than using the HEXLD progr...

Hi geeks! I've started learning Z80 recently (working my way through Mastering Machine Code on your ZX Spectrum by Toni Baker) and was just wondering about Z80 coding articles in classic speccy mags like Your Sinclair, Crash and Sinclair User. Is there a list or an index of coding articles containe...

_dw wrote: ↑Tue Feb 06, 2024 8:04 am The beam can also be escaped while scrolling the entire screen.
The beam only catches up with copying when the attributes change.

Excuse my ignorance, but what is the beam? I only ask because I am midway through building a routine that scrolls attributes both left and right but also up and down.