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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…
... after it happens). The ULA needs to fetch the ... it starts applying the contention a few cycles earlier, ... the bus when the ULA reads them, not later ... as well as correct any timing information stated above. I ... real machine but unfortunately ULA in my beloved 48k ... -
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…
... I added support for Pentagon timing instead, so I can finally ... bus behavior and timing. An explanation how the ULA replacement fetches the ... bytes without any memory contention would ... -
ULA snow effectIt's wintertime, you know. [quote="http://ramsoft.bbk.org.omegahg.com/floatingbus.html"]when the I register falls in the range 0x40-0x7F then the UL…
... it doesn't apply contention to take precedence as ... address generated by the ULA (who wants to read ... two addresses. Therefore the ULA reads the data from ... After that 128T, the ULA is busy drawing the border ... once borked up the timing somehow such that it ... -
Question of contentionI'm not desperate to go digging through technical descriptions in depth, but one thing bugs me about the Speccy's video contention model - and that's…
... amount of data the ULA is extracting from the ...
So can the ULA access memory faster than the ... And then there's the contention pattern where the memory ... br /> So why does the ULA appear to fetch data in ... some odd stop-start timing thing going on between ... -
I/O contention model questionHi everyone, Sorry for my poor english. Together with a friend we are working on ZX Spectrum 48k implemented in FPGA. We have found bug in the Spect…
... to lead to the following contention patterns:
High ... /> in 40 - 7F? | Low bit | Contention pattern
------------+---------+-------------------
No | Reset ... cycles)
During _reading_ from ULA this can't be right ... -
Harlequin ZX Spectrum Clone now 100% compatible!Hi all! The Harlequin ZX Spectrum clone now shows full timing compatibility with the ZX Spectrum! 8-) Both the ULA IO and memory contentions are fa…
... Spectrum clone now shows full timing compatibility
with the ZX ... ! 8-)
Both the ULA IO and memory contentions are ... that will test the _memory_ contention
(or anything else for ... -
Spectrum ULA replacement!Hi gang.. The Speccy 48 ULA Replacement is *almost* here ;) There has been lots of activity in building the CPLD board, sorting out some irritating…
... gang..
The Speccy 48 ULA Replacement is *almost* here ;)
timing glitches and getting sidetracked researching ... with ULA replacement doesn't quite boot up yet - some timing issue ... -
ULA Plus and Interlace.May be a bit late to suggest this, but here goes. Did the original Speccy ULA actually output a proper PAL interlaced image, with timing pulses on a…
... Speccy ULA actually output a proper PAL interlaced image, with timing pulses ... frame?
Now, does ULA Plus generate a proper interlaced ... -
ULA Price Poll - You get to chooseIt is difficult to set the price of the book. If it is too low I will undersell my efforts, too high and I overcharge. So choose what you would be w…
... content not only documents the ULA circuit, but also full ... details of the Ferranti ULA range, images of the ... technology that was the Ferranti ULA, or the principles and ... supported by full circuit and timing diagrams, photographs and helpful illustrations ... -
128K Contention - How to get it right?With my recent hardware hackery, I've built a 128K (toastrack) clone. I can't quite get the contention right though. What I'm lack is a clear descri…
... 0x7ffd, 0xbffd and 0x3ffd port contention behaviour.
To correct the excessive contention, I replicated ULA14 and ... someone describe accurately the contention behaviour for the 128K ... differentiate between machines through timing?
3. What ... -
4116 SRAM replacement (and ULA timings).As mentioned in another thread, I have spent quite a lot of time experimenting with different circuits and components for using a static RAM IC to re…
... perfectly with a 5C112E ULA. I have just been ... whatever their native (version 6) ULA happened to be.
... much more severe as the ULA (I assume) warms up ... makes me think the ULA must sometimes wrongly read ... a difference in the timing of the presentation of ... -
Zero 0.5 ReleasedAfter a bit of a hiatus, the next update of Zero is now available [URL="www.ramtop.wordpress.com"]here[/URL]. Feedback and bug-reports appreciated! …
... full screen.
+ Added ULA Plus and +3 disk support ... /> - Fixed IN contention (Woody).
- Fixed ULA PLus emulation that was ... renderer (Woody).
- Fixed timing for EX (SP), HL/IX ... . (Obo)
- Fixed ULA Plus timing and colours (Andrew Owen)
Timing in loading routinesJust for curiosity I have done some experiments with SAVE command in accurate emulators, and then analyzing the generated WAV and I have obtained lit…
... don't take account the contention. There are two instruction with ... contention, OUT (FE),A that affects ... one.
All this timing is for 48K machines. The ... compared with the teorical (without contention) values. If we take the ...Nasty 'Gotcha' for multicolour timingI thought I would be better developing my multicolour routine on the 48K first, being the slowest, so it would then be sure to work on the 128K varia…
... awkward it even throws up timing differences between the 128K and ... hit all the most awkward contention.[/QUOTE]
I think ... cycles (extended to 16 by contention). But then I should ... to get ahead on the contention cycle. Assuming that writing those ...Understanding contentionI'm trying to understand contention and its implications when some "weird" bus cycles (such as I/O cycles with I/O addresses in the contended memory …
... 'm trying to understand contention and its implications when some ... O contention. Memory contention causes T1 to be enlarged until the ULA ... br />
Also: memory contention makes T1 to be enlarged ... instance, to avoid memory contention) that begins at the ...128K memory bank selection to avoid contention issuesI'm currently developing a game and I'm trying to get my head around the memory contention issues of the various 128K/+2/+2A/+3 spectrum models in or…
... my head around the memory contention issues of the various ... . Also that when the ULA is drawing the screen it ... is "contending" with the ULA for access to the data ... and the ULA has priority. With this ... what is the cause of contention for banks 1,3, ...Memory Contention: A Hypothetical Fix?I have just had this crazy thought: If one were to wire an additional memory chip, say a 6264 8Kx8 SRAM, in parallel with the main memory so that it …
... sets of RAM, while the ULA/ASIC is wired to read ... reduce the effect of memory contention considerably. Possibly with the addition ... the same address, that the ULA is reading from, would halt ...5C Horizontal timing vs 6C horizontal timing.Hi all, Just considering the timing difference in the video signal between the 5C and the 6C where the 6C ULA seems to have 50% longer horizontal …
... ,
Just considering the timing difference in the video signal ... the 6C where the 6C ULA seems to have 50% longer ...Anyone got a copy of 'Z80 for primates'?This Z80 lark isnt easy, in fact it makes me feel very much like Washoe the chimp trying to learn learn sign language, I just dont think I've got the…
... 32768 is sensible (for contention issues with ULA memory and all that ... use IM2 to get the timing right (and I'm guessing ...an idea that could be very very good...but also very very bad...Hello all! I've been having a chat with some of my friends round here that once loved the spectrum (well...2...as they're all heathens round here...)…
... ULA emulation in FPGA, and also had Pentagon/Scorpion/Sinclair spectrum timing ... different z80 than the memory contention or ULA. There aren't a ...Weird loaders; 1) Why? 2) How? (Curiosity question)Hello again. Sorry to be asking/posting so much today, but I've just arrived here and am plumbing the depths of nearly 22 years of making cups of te…
... avoid the ULA contention issue,which would knacker up the precise timing needed ...Weird loaders; 1) Why? 2) How? (Curiosity question)Hello again. Sorry to be asking/posting so much today, but I've just arrived here and am plumbing the depths of nearly 22 years of making cups of te…
... avoid the ULA contention issue,which would knacker up the precise timing needed ... numbers take account of the contention on 'port #fe'? If not ...Z80 cycle contentionHi, Does anybody knows exactly when the ula halts the Z80 clock during a memory r/w cycle? I mean which Z80 clock cycle, T1 or T2? Thanks..
... i have another question about Ula timings..
after 14336 T ... screen.. this means that the ula is going to read this ... that the timing is different on the +2a/+3 - memory contention here ... .com/cssfaq/reference/48kreference.htm#Contention"]48k[/url] and [url=" ...non standard loader bar coloursAs with my speedloader thread, when did non standard colours start to appear and who came up with the idea and what was the reaction?
... time (the ones that the ULA/TV is tracing at the ... RAM may cause timing problems due to memory contention so such a ... , it is due to memory contention that you will not find ...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…
... />
If you analyse the ULA at the hardware level, you ... every 8. The timing of the IO contention however is [I ... 14343 experience memory contention.
The memory contention timing is as it ... lower 16K 1Tstate before the ULA wants it, and returns ...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…
... IRQ 3 states later after ULA pulls INTREQ low. I don ... earliest 1 cycle after the ULA pulled it low. But not ... />
[QUOTE]The timing of the IO contention however is different. Again ... is contended by the memory contention!!)[/QUOTE]
Well, ...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…
... saying about the actual timing of the contention and byte fetches).
ULA [/QUOTE]
Probably. The ...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…
... confident that is what the ULA is also doing.
contention timing is also correct and contention starts at ... access back and the ULA would continue to read ... the memory when the ULA is. If we accept ... /> I am writing a ULA internals paper at the moment ...
