-
Issue 3 expansion connector problemI am having problems with an issue 3 Spectrum, that otherwise works fine, but does not recognize either the Interface 1 or DivMMC/Enjoy (which are bo…
... 's post, some Z80 CPU's have a bad /M1 line (some ... you've experienced.
Z80's are still manufactured as ... -
ZX81 and Analogue TVsI recently bought a really nice ZX81 on ebay in amazing condition, but I'm having issues tuning in an old analogue TV to lock onto the signal. I und…
... will see various brands of Z80 CPUs for example.
... Sometimes the ULA, the Z80 CPU and the ROM are ... porch” part of the video signal. This causes many colour ... ” part of the video signal, and so is the ... board fits on the Z80 CPU and effectively changes one ... -
'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... ULA, there is no video signal information. However, the modulator ( ... still produce the UHF carrier signal. Some TV's may ... encoder chip, working modulator, working Z80 and working ROM, you will ... by the communications between the Z80 and the ROM/floating bus ... -
'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... ULA, there is no video signal information. However, the modulator ( ... still produce the UHF carrier signal. Some TV's may ... encoder chip, working modulator, working Z80 and working ROM, you will ... by the communications between the Z80 and the ROM/floating bus ... -
Weird 1982 Copyright message after cap change.Hello All, As mentioned before I had a busted Issue 6 48K Spectrum+, one of the capacitors had leaked, and trashed the keyboard membrane ribbon. Us…
... of the Z80 CPU is controlled from the clock signal, which comes ... -
z80 reverse engineeringI came across Ken Shirriff's blog today where he is reverse engineering the Z80 from images of a Z80 die. I guess this may be of interest to those of…
... reverse engineering the Z80 from images of a Z80 die. I ... providing 100% compatibility with the Z80, though... and might even help ... explain some questions about the Z80's reliability, maybe?
... chance of finding that the Z80's 'M1' line has stopped working ... -
Weird 1982 Copyright message after cap change.Hello All, As mentioned before I had a busted Issue 6 48K Spectrum+, one of the capacitors had leaked, and trashed the keyboard membrane ribbon. Us…
... of the Z80 CPU is controlled from the clock signal, which comes ... -
z80 reverse engineeringI came across Ken Shirriff's blog today where he is reverse engineering the Z80 from images of a Z80 die. I guess this may be of interest to those of…
... of finding that the Z80's 'M1' line has stopped working ... clear to me whether the M1 line itself is particularly ... I don't know, but M1 is not used on the ... won't boot and the Z80 gets replaced.
... Maybe the thing is that M1 are "misterious" (hey, my ... -
z80 reverse engineeringI came across Ken Shirriff's blog today where he is reverse engineering the Z80 from images of a Z80 die. I guess this may be of interest to those of…
... /> Maybe the thing is that M1 are "misterious" (hey, my computer ... seemed to be that faulty /M1 lines going unnoticed would still ... Spectrums being found with faulty /M1 lines. Now that I think ... and the Development of the Z80 Microprocessor[/URL] back in 2007 ... -
Dumping Microdrives (to a PC, not to a skip)Morning/Afternoon/Evening chaps, What do people use for getting their data off a microdrive quickly? I know of at least one project which does it ra…
... ;799063]My method requires no z80 coding, and would actually work ... see a tiny bit of signal on the pin, but obviously ... -
Weird symptom number 2...I got a new keyboard membrane for my Spectrum+ plugged it in and low and behold the weird left to right printing of the copyright message disappeared…
... show if the clock signal to the Z80 CPU was good or ... -
Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... features. You can implement a Z80 and a ULA on the ... can clock the on-chip Z80 at higher speeds than you ... can get a real Z80.
I'm ... ). Video output is a VGA signal. It's on-FPGA CPU ... is the T80 softcore Z80; CPU speed is selectable up ... -
Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... metal layers vertically to allow signal routing, you leave a gap ... probably not news to you), signal integrity (you need to ... more heat which changes local signal characteristics!), an automatic layout like ... the same guys doing the z80 did the 8080 they probably ... -
Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... certain shape that aids in signal routing. They're all adders ... /> The Spectrum ULA and the Z80 could have been implemented in ... a perfect FPGA implementation. The Z80 also saw at least one ... " instruction, whereas on the CMOS Z80 this is reliable.
Tinkering with DMASo, some afternoon tinkering... [img]http://photo.alioth.net/tmp/dma_small.jpg[/img] The purpose of this all is to see what's possible using the Xi…
... ]
Doing DMA with the Z80 I know there's the ... since that uses the WAIT signal instead of gating the clock ... (listening to the WAIT signal takes virtually no resources, it ... same memory timings as the Z80 is guaranteed to work).Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... /> ie: software running on a z80, (which is implemented on a ... , it cannot be checked for signal rise times, it cannot be ...DIVMMC my version512 ram, 8kb Flash ROM, esx dos, 2x thru, micro SD card slot,prototype board: [URL=http://www.fotosik.pl/showFullSize.php?id=18408198292851f7][IMG]h…
Do you have a spare Z80 to test with, sometimes not only the clock signal is borderline.DIVMMC my version512 ram, 8kb Flash ROM, esx dos, 2x thru, micro SD card slot,prototype board: [URL=http://www.fotosik.pl/showFullSize.php?id=18408198292851f7][IMG]h…
Yes, the M1 problem on some Z80's. But these should be OK.
The board does the same thing with three 48K Spectrums, and the divMMC/Enjoy works fine in all those.
I guess next thing to try is get some other brand SD cards.New multisystem floppy interface (spectrum 16Kb/+2A/CPC464)Dear all, I would like to show you my new extern floppy interface. Same interface can be used for both, CPC and Spectrum systems. CHARACTERISTICS …
... a problem with the /RESET signal.
Seems like drive selection ... , and using it instead direct signal from computer.[/QUOTE]
z80 NRST inverted by one of ... network connecting NRST of the z80, or NRS of the ASIC ...New multisystem floppy interface (spectrum 16Kb/+2A/CPC464)Dear all, I would like to show you my new extern floppy interface. Same interface can be used for both, CPC and Spectrum systems. CHARACTERISTICS …
... if I invert the NRST signal before to connect to the ... not working either if the signal is not connected to the ... schematic is correct that the signal that goes to the resistor ... of the NRST to the Z80. (also fed to the RESET ...Speccy Vs Amstrad CPC Vs C64I hope no one minds me posting this here as well as in the announcements section. I'll delete it if there is a problem. It's childish fun but can I …
... do on any of the z80 machines with AY chip:
signal to generate audio was how ...Speccy Vs Amstrad CPC Vs C64I hope no one minds me posting this here as well as in the announcements section. I'll delete it if there is a problem. It's childish fun but can I …
... do on any of the z80 machines with AY chip
signal to generate audio was how ...Spectrum 48K Ferranti ULAIs there anywhere to get hold of the ICs in the subject? Martin
... like) to shape the input signal so the FPGA has no ... can be placed in the Z80 socket, bypassing the old DRAMs ...HALT: Why always 4ts?Instruction breakdown of halt is like that: PC 4ts. That means it fetches instruction byte from ram which tooks 4 ts and then does nothing and read…
... ;819865]I believe the Z80 internally executes repeated NOP's ... br /> [LIST]
[*]Does the Z80 continue to fetch instructions while ... halt state is a normal M1 (fetch) cycle [/QUOTE]
... read are discarded, and the Z80 executes NOPs internally.
...ZX Spectrum issue 6a - yellow border problem<p>Hello!</p><p>I have problem with my Sinclair ZX Spectrum issue 6A, 48K. </p><p>I have changed low memory (all 4116 IC's) and coil, all electrolyti…
... , try to synchronise to the Z80 /MREQ pin.
Note ... that if the Z80 does not have a clock signal, it will ... check every pin on the Z80 (except the 0V/GND and ...ZX Spectrum issue 6a - yellow border problem<p>Hello!</p><p>I have problem with my Sinclair ZX Spectrum issue 6A, 48K. </p><p>I have changed low memory (all 4116 IC's) and coil, all electrolyti…
General Z80 fault finding:-
Check the ... are pulsing clock (pin 6) /M1 (pin 27) /RD (pin 21 ...Features that are still wanted in Spectrum emulation.Features that are still wanted in Spectrum emulation. 4 USB joystick/gamepad input for real multiplayer games - Yes, Bomb Munchies.... - Sinclair 12…
... whether it’s possible to signal keypresses using the expansion port ... also interested in knowing which Z80 data bus lines are left ...Features that are still wanted in Spectrum emulation.Features that are still wanted in Spectrum emulation. 4 USB joystick/gamepad input for real multiplayer games - Yes, Bomb Munchies.... - Sinclair 12…
... check for (I vaguely remember) !M1 high and A5 low. The ... learnt of the role of /M1 for interrupt acknowledgement. I gather ... of the interrupt, when the Z80 is fetching the interrupt vector ...Newbie Hardware QuestionsI just recently aquired my first Spectrum, a +2, and I'm in the process of getting acquainted with it. Being a newbie I had some questions, which …
... adapters I have support the signal format when you use the ... be fair, the pricer AV-M1 doesn't sync on RGBHV ... and just barks about the signal not being supported.
M1, that I want to try ...
