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Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... bit with memory contention and floating bus stuff in ZXDS and there ... and the Z80 can generate interrupt for the first time at ... However, as far as the floating bus is concerned, the very same ... .html"]tech doc[/URL] about floating bus.
Ramsoft's [URL=" ... -
Floating bus on 128K models[b]Background:[/b] i need run code with interrupt enabled but i need use stack instruction to maximize performance in copy/shift/mirror routines. dur…
... ] i need run code with interrupt enabled but i need use ... /> questions are:
1) is floating bus present on all of 128 ... -
Pentagon floating bus timingI wanted to take a little break from working on the ZXDS UI yesterday, so I added support for Pentagon timing instead, so I can finally enjoy the lik…
... and exact info about the floating bus behavior and timing. An explanation ... -
Emulating a +2A with floating bus modBefore I start hacking Fuse's source... Does any existing emulator have an option to behave as a +2A with the [URL="http://www.secarica.ro/html/plus…
Before I start hacking Fuse's source...
Does any existing emulator have an option to behave as a +2A with the [URL="http://www.secarica.ro/html/plus3_hardware.html#inFFport"]floating bus modification[/URL]?
-Stephen -
Spectrum +2A floating bus portHi As I discovered in the past, Spectrum +2A (and probably +3) do have floating bus port. But it is not shown on all unused ports, only on some po…
... (and probably +3) do have floating bus port. But it is not ... that +2A does not have floating bus port, but it's incorrect ... -
ANN: Spectaculator 2.5 available for downloadHi. I've just released a new version of Spectaculator, available from [url="http://www.spectaculator.com/"]http://www.spectaculator.com/[/url]. Hopef…
... Islands now load (was an interrupt frequency problem).
Latest issue ... />
Emulation
- Floating bus emulation as per Ramsoft technical ... -
Tricks with IN 31It's generally considered unwise to use a Kempston joystick's fire button to start a game, because the floating bus effect can make arbitrary data ap…
... start a game, because the floating bus effect can make arbitrary data ... upper border (using a short interrupt routine in IM2 to make ... -
Enable 128kB paging in emulatorFrom Zx Spectrum documentation ([url]http://www.worldofspectrum.org/faq/reference/128kreference.htm[/url]) [CODE][SIZE="1"]When memory is being pag…
... going to change. If normal interrupt code is to run, then ... 0x7ffd produces no special results: floating bus values will be returned as ... -
Games that won't work with the +2a/bIs there a list of all the games that don't work with the +2a/b? Like Fairlight for example. Ta :)
... also the different timings, non-floating bus etc.? Note: I am talking ... depends massively on timing and interrupt tricks.
If it ... -
Beginner InfoI have trying to find some hardware information for use with assembly coding but havn't had much luck. For instance. How do I redirect the vertical …
... on all 8 data bus bits, a floating bus means 255 is sitting ... the data bus. So when the ULA's vbi interrupt occurs, the ... can also find a generic interrupt service routine that is able ... hooks on a specific interrupt vector. When an interrupt occurs, each of ... -
Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... seem start counting from the interrupt (woody's float48k). And yet ... exact time until the next interrupt. Is this perhaps what your ... contended IO read of the floating bus (because that T-state is ... -
The new GP2Xpectrum releases threadYeah, I know the thread title isn't exactly too original, but I've decided that just one post to hold all updates makes more sense than a lot of smal…
... instead of 4.
- Improved floating bus emulation, now passes floatspy test ... not perfect, and fixing the interrupt time has caused trouble with ... -
Group Order of Internal/External Kempston Turbo InterfacesI have contact Velesoft ([url]http://velesoft.speccy.cz/kmturbo-cz.htm[/url]) about the production of internal or external kempston turbo interfaces …
... add:
-floating bus stabilisation ( return interrupt vector #FF to data-bus )
-fuller ... -
+2A, are they all this incompatible?My +2A does not seem to be faulty but the number of games that don't run on it are silly. Scooby Doo(Elite), Crazy Cars , Turbo Outrun, Vindicator(im…
... issue with some games (no floating bus) and sometimes a ROM issue ... issue causing the mode 2 interrupt vector to go astray and ... -
MB02+ software and system developmentsThe following text was (before last modification) first published here: [url]http://www.sintech-shop.com/forum/board.php?boardid=20[/url] As discuss…
... /> ei
halt ;wait for interrupt (for correct K-MOUSE detect ... disable read 7FFD, register A=floating bus data
- set flag Z ... -
Fast screen writesI wondered what the faster than LDIR methods of writing to the screen were.
... after the vertical blank/maskable interrupt. That way, not only ... . Write a very short interrupt routine that just does a ... ). You can do your interrupt stuff after drawing the screen ... bottom border by reading the floating bus and looking for a particular ... -
Data bus at interrupt timeIt is "well known" that some peripherals can put values other than 0xff on the data bus at interrupt time, thus meaning that IM2 is slightly more fid…
... on the data bus at interrupt time, thus meaning ... in interrupt time (only with pull-up data bus via ... fixed vector table adress (correct floating bus value):
===========================================
bus correct 8bit low adress ... -
Machine Code Routine of the weekHow about a thread that has a routine each week that is in [B]assembly language[/B] and is also described in great detail what the hell is going on …
Just been messing with the interrupt sync code and this tells ...
in a,(c) ; read floating bus on cycle 14338
in a,(c) ; read floating bus on cycle 14339
Question on copying screen bufferHi, Al my prevoius games were copying graphics directly to screen memory starting at 16384. Now I'm experimenting with screen buffer where I could d…
... floating bus (not compatible with all Spectrum models), and waiting for the interrupt ... is to wait for the interrupt, then do some useful processing ...IM2 Loading on +3EHi there Speccy Guru's, As some of you know, I've spent a while building the ultimate image for +3e, it's currently at 6000+games and demos and i've…
... these demos set up an interrupt table in lower ram. I ... DivIDE places data on the floating bus. This will kill this idea ... , all speed fixed - timing fixed - interrupt fixed
7UP
Tricks with IN 31It's generally considered unwise to use a Kempston joystick's fire button to start a game, because the floating bus effect can make arbitrary data ap…
... upper border (using a short interrupt routine in IM2 to make ... more interfaces then value of floating bus can be unstable !!!
floating bus. But all modern interfaces (and ...GUI/OS for the Spectrum?Hi, Is anybody working on a WIMP/GUI system for the Spec? Is there anything current out there? [url]http://snakeoillabs.com/wordpress/2005/10/30/8…
... back?
To avoid floating bus problems you can read a ... reading memory immediately after an interrupt). This is what the Spectranet ...general beginner queriesHi, I bought myself recently a +3 and a devide extension. I was not in touch before with the speccy, but I am really surprised and delighted about th…
... is that it fix the "floating bus"-issue which can crash some ... coded games with incomplete vector interrupt table.general beginner queriesHi, I bought myself recently a +3 and a devide extension. I was not in touch before with the speccy, but I am really surprised and delighted about th…
... is that it fix the "floating bus"-issue which can crash some ... coded games with incomplete vector interrupt table.[/QUOTE]
[B ... )
- fix stability of data bus with IM2 vector
- enable ...general beginner queriesHi, I bought myself recently a +3 and a devide extension. I was not in touch before with the speccy, but I am really surprised and delighted about th…
... is that it fix the "floating bus"-issue which can crash some ... coded games with incomplete vector interrupt table.[/QUOTE]
Thats ...What paging scheme is the "standard" for 128K models?Sinclair implemented an arrangement so that even numbered pages are non-contended, and odd numbered pages are contended (quoting from memory, haven't…
... ).
Working out the interrupt timing will be fun. It ... go as well. What about floating bus? Is that known to work ...What paging scheme is the "standard" for 128K models?Sinclair implemented an arrangement so that even numbered pages are non-contended, and odd numbered pages are contended (quoting from memory, haven't…
... ;583148]Working out the interrupt timing will be fun. ... 2 to run an interrupt handler that OUT's ... it is, then the interrupt will trigger on h-retrace ... as well. What about floating bus? Is that known to ... work?[/QUOTE]
FLoating bus cannot work as there's ...Disable interrupts?Well, I've read the bits from the David Webb book about interrupt modes and (vaguely) appreciate the principles behind having a vector table, after r…
... value you get on the bus is pretty much deterministic. If ... get 0xFF during the vblank interrupt. Only if you have any ... what they put on the bus. I.e., it works ... get screwed over by the floating bus (because it may not be ... what value is on the bus on the speccy.Maritrini and Cray 5 loading problemsHas anyone else here had issues loading either of these on a 128k? No matter what I try, both these games refuse to load properly. I can get both t…
... behaviour, EVEN when secaria's floating bus fix is implemented (a resistor ...Definitive list of games incompatible with +2A/+3 and of compatible versions (if any)I am trying to compile the definitive list of games which are incompatible with the +2A and the +3 and of their compatible versions, if they are pres…
... interrupt vector so it'd fix some things. Others rely on floating bus ...
