Spectrum Computing

This book, the first three chapters, is exactly what you need:
https://spectrumcomputing.co.uk/entry/2 ... e_Language

Story in The Register, today:
https://www.theregister.com/2024/04/26/ ... 6_bit_z80/

These are "just" binary compatible, aren't they? Unless I miss something, ez80 (and z180) may be good enough for CP/M, but they won't replace Z80 where timings are critical. Yep, that's right. I've just bought an Agon Light, not had much chance to experiment with it yet. It has an eZ80 wh...

Adventure A: Planet of Death. IIRC it came with my Spectrum, along with Horizons of course.

See here, particularly pages 6 and 9: https://archive.computerhistory.org/resources/text/Oral_History/Zilog_Z80/102658073.05.01.pdf Some folks might also be bemused by Shima's comments on p.10, too, regarding IXL/IXH etc. (In) the new instruction set, the prefix instruction is able to redirect the s...

This looks great, I've always liked the IF1 design, could be useful for DIY interfaces too

Without going to check, I don't think there's any reason why the plot/draw routines could not take advantage and draw on the lower two lines Alas the ROM routine PLOT-SUB routine calls PIXEL-ADD which checks the upper y-coordinate limit (175d). So you'd need a bespoke routine, see p.19-22 of: this ...

Yep, I think one of the fairly rare areas where the Speccy scores over the BBC Micro is the BASIC editor, even the 48k one, when you want to edit an existing line (...) On the other hand, it's annoying that you can only cursor left and right in the 48k editor, as it takes an age to reach the end of...

For writing z80 code, my preference now would be similar to Ralf's example, maybe a brief description with register inputs, and one or two line comments in a block. I guess when you're writing z80 code the comments are really for yourself rather than others as it's normally a 1-person job. ^This. I...

1024MAK wrote: ↑Thu Feb 01, 2024 12:40 pm The extra transistor (TR6 for issue 3 and later boards) for issue two boards was normally placed on top of the processor
Mark

Of course, yes ... my mistake ... it's been a while since I opened it up

Hence upgrade kits using OKI DRAM were sold with 74LS157 modified by the supplier or with a daughter board (which rerouted the relevant signals). Then the owner just fitted the parts into the existing sockets on their ZX Spectrum board. Mark Yes, this is what I recall. The Fox upgrade used a daught...

Page 22 here (and elsewhere) may also be of value if you're experimenting with the edge connector:
https://archive.org/details/bitsavers_z ... /mode/2up

Dr beep wrote: ↑Thu Jan 04, 2024 10:04 pm Take a look on this "old" trick.
https://worldofspectrum.org/forums/discussion/33911/

Yes, I remember this - a brilliant bit of lateral thinking!

equinox wrote: ↑Thu Dec 28, 2023 12:30 am I can't find it anywhere online, to link to

Is this the one?
https://worldofspectrum.org/forums/discussion/6093/

This article, an interview with Richard Altwasser, provides some interesting context, implying that FLASH and BRIGHT were added after the decision to use 3+3 bits for colour encoding was made. Looking at the block schematic in the patent (posted earlier in this thread) it does look to me that implem...

zx64 wrote: ↑Tue Dec 12, 2023 1:51 am Indeed. They even have patent for this.

Yep, here it is:
https://patents.google.com/patent/EP010 ... Ltd&page=3

Check out page 41-42 of Ian Logan's Spectrum Microdrive Book . It should be a relatively simple task to add a counter to the program on page 41 to add up the '1's or '0's (instead of printing them) depending on whether you want to know 'free' or 'used' space. Note that each sector is 512 bytes, so y...

Here's my approach using embedded CODEs instead. 10 DIM a$(3,14) 20 RESTORE 30 FOR n=1 TO 3 40 READ b$ 50 LET x=LEN b$ 60 LET a$(n)=CHR$ x+b$ 70 NEXT n 100 REM demo 110 PRINT "Length","String" 120 FOR n=1 TO 3 130 LET x=CODE a$(n,1) 140 LET b$=a$(n,2 TO x+1) 150 PRINT x, BRIGHT 1...

It does seem to struggle with string handling, though: >Please write me a program in Sinclair ZX Spectrum BASIC to slice the first and last characters from a string of ten characters 10 INPUT "ENTER A 10-CHARACTER STRING: "; A$ 20 IF LEN A$ <> 10 THEN PRINT "PLEASE ENTER A 10-CHARACTE...

There's always a flowchart for something it seems

https://www.labelplanet.co.uk/labels-bl ... ve-labels/

Done, and good luck with your business

Great good to know

I don’t have a +3, but this intrigued me – so, I looked here https://worldradiohistory.com/UK/Bernards-And-Babani/Babani/Babani-251-Computer-Hobbyist-Handbook.pdf (Fig 2.7, CPC port) and then here https://zxnet.co.uk/spectrum/schematics/Z70835.pdf (+3 schematic) and, based on this alone, the +3 port...

Yes, a joystick port can have eight input lines, of which, four are direction inputs and four are fire or function buttons. However, if using a 9 pin D connector (Atari joystick compatible), if we include a +5V supply, then we will have a maximum of three fire button inputs. Mark Agree. Not a joyst...

Some general principles here, although this is just for 16K ROM/RAM and optional 32K upgrade, not 128K. But principles are similar. Anything above 32K for the upper memory would obviously need (fairly simple) paging circuitry. https://archive.org/details/your-spectrum-magazine-02/page/n36/mode/1up?v...