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Port 0x7ffd Partial DecodingI'm trying Pitfighter on my emulator and it runs in +2A/+3 mode but crashes in 128k/+2 mode. I traced it down to an OUT instruction which sends 4 to …
... />
Now after reading about partial decoding in the faq I made ... /> I can take out the partial decoding (respond to 7FFD only) to ... correctly or have I misunderstood partial decoding? -
Spectrum Ethernet updateThis week's theme is [B]Frustration.[/B] [url]http://spectrum.alioth.net/doc/index.php/Current_events[/url] But I'm confident it will come right.
... is an unavoidable consequence of partial port decoding. I'm trying primarily ... uses 32K ports thanks to partial decoding, and the memory paging for ... more ports, as does the AY.
I may be ... -
Minor Update to Gasman's Midi2BEEPDon't know whether this is worthy an announcement, but for those of you who enjoyed Gasman's midi2BEEP utility, a new variant has been made called mi…
... )?[/quote]
If the AY was disabled you would still ... port address that uses the partial decoding of 128 and the fact ... -
WIP: ULAPlus hardware implementationThis aims to be an "almost" plug-in replacement for the Sinclair ULA chip fitted in Spectrum 16K/48K/Plus machines. It comes in a form of a small PC…
... and make a complete decoding instead of partial decoding, so freeing ports of ... raster, or even a complete AY-3-8912 chip on FPGA ... -
WIP: ULAPlus hardware implementationThis aims to be an "almost" plug-in replacement for the Sinclair ULA chip fitted in Spectrum 16K/48K/Plus machines. It comes in a form of a small PC…
... /O contention based upon partial decoding. That is, contend some ... to aid in this "early decoding" process: A0, A7, ... AY chip, I need to bring A1 to the ULA, as partial decoding ... to the in-ULA AY chip would been ... support for ULAplus and AY music without losing the ... -
Shadow ROM partial decoding not implemented in emulatorsOr at least, not implemented in Spectaculator, and it seems that not in Fuse too. [URL="http://www.speccy.org/foro/viewtopic.php?f=8&t=408&start=53"…
Or at least, not implemented in Spectaculator, and it seems that not in Fuse too.
[URL="http://www.speccy.org/foro/viewtopic.php?f=8&t=408&start=53"]A fellow member at speccy.org (zx81) has posted an interesting question on that forum ... -
Detecting +3 / +2AWhat's a simple but reliable way to detect if code is running on a +2A/+3? My first though was to try switching to ROM2 and then checking for the …
... testing for differences in the partial decoding of port 7FFD, as this ... -
Dual joystick interface schematic?Hi! Would anyone have a schematic for a dual joystick interface? Cursor or sinclair would either work. If not, I might try my hand at designing one.…
... my reading, I understand that decoding would be simpler for a ... ? Can one get away with partial decoding?
Thanks in advance! -
Spectaculator/Kempston/Spanish gamesWhen I use the kempston joystick emulation via the keyboard (cursor keys) in Spectaculator some Spanish games (e.g. Nonamed, Jungle Warrior) don't wo…
Surely it's just a matter of partial decoding of the address bus. Ports of 1F and DF would suggest the Kempston interface responds to any address with the bottom 5 bits set. -
Port 0x7ffd Partial DecodingI'm trying Pitfighter on my emulator and it runs in +2A/+3 mode but crashes in 128k/+2 mode. I traced it down to an OUT instruction which sends 4 to …
... an option to turn off partial decoding...
Actually, does any piece ... -
Port 0x7ffd Partial DecodingI'm trying Pitfighter on my emulator and it runs in +2A/+3 mode but crashes in 128k/+2 mode. I traced it down to an OUT instruction which sends 4 to …
... values to port FD! If Partial Decoding is off then the game ... just won't work. With partial decoding on in 128k/+2 mode ... Fairlight crashes without Partial Decoding but PitFighter crashes with Partial Decoding.
So ... -
Port 0x7ffd Partial DecodingI'm trying Pitfighter on my emulator and it runs in +2A/+3 mode but crashes in 128k/+2 mode. I traced it down to an OUT instruction which sends 4 to …
... was because I had disabled partial decoding to allow Pitfighter to run ... .
Fairlight 128k *needs* partial decoding (every other game I've ... />
I've now set partial decoding on by default and if ... -
Port 0x7ffd Partial DecodingI'm trying Pitfighter on my emulator and it runs in +2A/+3 mode but crashes in 128k/+2 mode. I traced it down to an OUT instruction which sends 4 to …
... or +2, those models have partial decoding. There's no real 128 ... -
How many expansions can a Speccy handle ?How many expansions / interfaces / addons can a Speccy handle ? I'm not thinking about the issue of powering the interfaces through the Speccy's PS…
... /O addresses (not necessarily through partial decoding, but because they really do ... -
More colours II (Was: Most popular new features?)The suggested 4xCLUT multi-colour solution never took off.
What about decoding the high byte as the ... work with it and the partial decoding might clash with certain interfaces ... -
RFC: ZXI hardware interface standardisationReposted from c.s.s to reach a wider audience [QUOTE=Andrew Owen] You may have noticed that there are more people making add-ons for the Speccy than…
... /> That's some pretty bad partial decoding by Kempston!
(Still not ... -
Cant DecideI have had a lot of spectrums in my time from the 16k to the +3 and as we all know they all have flaws. I am thinking about buying another and wanted…
... ZXATASP was due to only partial decoding of the Kempston port (it ... -
Cant DecideI have had a lot of spectrums in my time from the 16k to the +3 and as we all know they all have flaws. I am thinking about buying another and wanted…
... ZXATASP was due to only partial decoding of the Kempston port (it ... -
Cant DecideI have had a lot of spectrums in my time from the 16k to the +3 and as we all know they all have flaws. I am thinking about buying another and wanted…
... changing with each issue.
Partial decoding of Kempton port causes incompatibility ... -
Cant DecideI have had a lot of spectrums in my time from the 16k to the +3 and as we all know they all have flaws. I am thinking about buying another and wanted…
... changing with each issue.
Partial decoding of Kempton port causes incompatibility ... it up to use full decoding. There is no ULA in ... -
Memory upgrade for ZX Spectrum 16/48This is external memory upgrade for ZX Spectrum models with 16kB ram. Can be connect also to 48kB models, but need remove 8 dram chips (from sockets …
... /> [*]I/O ports decoding (ideally describing any [I]partial decoding[/I])
[*]I ... -
Hacking a Joystick InterfaceI have a DK'Tronics twin-port joystick interface that does Kempston and Sinclair 0-6 keys. I know it has only 14 lines connecting it to the edge con…
[QUOTE=Alien 8;523339]They clash, I think is the problem.[/QUOTE]
so it's a partial decoding issue with the joystick interface like with other hardware? -
Hacking a Joystick InterfaceI have a DK'Tronics twin-port joystick interface that does Kempston and Sinclair 0-6 keys. I know it has only 14 lines connecting it to the edge con…
... ;523345]so it's a partial decoding issue with the joystick interface ... -
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…
... +3 by looking at the partial
;; decoding of "port 0x7ffd"[/code ... -
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…
... +3 by looking at the partial
;; decoding of "port 0x7ffd"[/code ... high? (ie the 128 address decoding only considers A1 and A15 ... -
writing an emulator-newbie needs helpHi, this is my first post here. I decided to write a minimalistic emulator of ZX Spectrum-no emulation of advanced peripherals, no emulation of sound…
... to describe it is "partial address decoding") an ambiguity arises and ... the ULA (due to partial decoding again?), but it is ... A0 is low. As partial decoding is employed, in order ... Spectrum compatibility, the same partial address decoding should be used, as ... -
writing an emulator-newbie needs helpHi, this is my first post here. I decided to write a minimalistic emulator of ZX Spectrum-no emulation of advanced peripherals, no emulation of sound…
... term to describe it is "partial address decoding") an ambiguity arises and ... the speccy uses incomplete/lazy/partial decoding (or whatever it's called ... identifies the ULA (due to partial decoding again?), but it is recommended ... -
NEW KEMPSTON interface for ZXHi. Lotharek has released a new KEMPSTON interface for people who doesn't need AY on-board and want to have some really small device. [url]http:/…
... ).
It currently uses partial decoding for Kempston (xx0xxxx1) and Fuller ... perform a more issue-free decoding, if needed.
On ... -
Distinguishing between models?I'm running the risk of being pointed to the faq here, so sorry in advance. Something I'm trying out requires that the program can distinguish betwe…
... just to use the different partial decoding of "port 0x7ffd" rather than ... -
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…
... /+3 by looking at the partial decoding of port "0x7ffd". Obviously this ...