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ZX Spectrum CartridgesI have been thinking of "cloning" ZX Cartridges for a while (case, board and silicon skirt), to be able to make new releases or replace damaged cartr…
... "watch" the address bus (plus /M1) and when the device logic ... data to the CPU (if /M1 is included, this will be ... bus all determine if the Z80 reads the Spectrum ROM, garbage ... -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... they are not 'glitching' the signal just doesn't look like ... picture. I think some signal to the z80 is not correct. The ... -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... they are not 'glitching' the signal just doesn't look like ... picture. I think some signal to the z80 is not correct. The ... -
What should your speccy have come with ?:) I was thinking about this earlier. What changes should of been made to the Speccy when you purchased yours ? Realistically this topic really…
... timing, while the Z80 divides the external clock signal down to provide ... system, hence why with the Z80 memory cycles are not the ... /> One slight advantage that the Z80 has over the 6502, is ... to the greater number of Z80 instructions and hence operations, code ... -
My re-creacton of the Z80 8-bit Universal IDEI looked into my draw with various bits & bobs for PC and I found there a CF-IDE adapter, HDD ribbons and two CF cards. So, I was thinking to myself,…
... with CF as the /CS signal is expected to stay a ... done. According CFA specs. Alas Z80's signals come and go ... and there is no delayed signal available. I see this timing ... -
Speccy won't bootHi all, I've got an issue 3 48k that won't boot properly. When I turn it on, it either does one of the two following things, it either displays a …
... the ULA to Z80 trace save for carrying the signal out to ... -
Replacing z80Hi all, I've just finished removing my z80 and installing it back in in a socket. Surprisingly I haven't broken anything in the process and the sp…
... the speed of the clock signal that feeds it. So for ... a ZX Spectrum, any Z80 rated for 4MHz or greater ... know, only Zilog produces new Z80 CPUs now. But in the ... -
Looking for advice on building a HarlequinNew member here. From the US. My first computer was a Timex Sinclair 1000 back in the early 80s (in fact, I got one of the first batches sold in th…
... to do those things? A Z80 is going to have a ... is the way the video signal is generated in the first ... -
Repair Zx Spectrum +2 Blackhello there, just found a Zx Spectrum +2 Black edition Issue 1 board that doesnt appear anything on the screen, even led dont power on,i have tes…
... (IC1) into a Composite video signal.
There's no point ... connector, pin 11 of the Z80, pin 28 of the ROMs ... -
ZX Spectrum 48k issuesHi all! A couple of days ago I bought my first 48k Speccy off ebay (I already own a beautiful QL expanded with QubIDE interface and 640k ram). It was…
... RAM from ROM/upper RAM/Z80 data lines, may need adjustment ... /> Another note: Z80 product specification indicates that clock signal [i]should[/i ... , from all my experience with Z80 based hardware, I don't ... 's very critical for most Z80 chips out there - as long ... -
ZX Spectrum 48k issuesHi all! A couple of days ago I bought my first 48k Speccy off ebay (I already own a beautiful QL expanded with QubIDE interface and 640k ram). It was…
... /> Another note: Z80 product specification indicates that clock signal [i]should[/i ... , from all my experience with Z80 based hardware, I don't ... 's very critical for most Z80 chips out there - as long ... />
I can confirm that. Z80 it's like a WW ... -
Any one know what this mod isOk +2b with a mod anyone know what it is and why its there and if its worth removing cheers [img]http://i.imgur.com/p5IG6Ec.jpg[/img]
... issue 2 with the clock signal inversion.
Is there ... capacitor on the top of Z80 CPU?
The idea ... -
Help understanding the Z80.So I have a Z80 CPU and a 32k ram chip. I understand how they connect. (Data and address busses, chip select etc.) But how would i input information…
... address buss. How would the z80 (or rather the system) know ... a ram and ROM signal pin on the z80(well Rd and ... -
Help understanding the Z80.So I have a Z80 CPU and a 32k ram chip. I understand how they connect. (Data and address busses, chip select etc.) But how would i input information…
... address buss. How would the z80 (or rather the system) know ... a ram and ROM signal pin on the z80(well Rd and ... .[/quote]
The z80 has no idea where the ... 15 address lines while the z80 has 16. You'll ... chip to respond if the z80 addresses 32k and up, ... -
128K Toastrack (Noisy video output)Hello there guys! Need all of yours guides and advices. Some time ago I bought a nice looking 128K from eBay (motherboard v6K) and put it aside for…
Some Z80 CPUs from Zilog might have a faulty /M1 line. It is well know issue regarding a compatibility with any inference which requires the /M1 active. -
128K Toastrack (Noisy video output)Hello there guys! Need all of yours guides and advices. Some time ago I bought a nice looking 128K from eBay (motherboard v6K) and put it aside for…
... "]Some Z80 CPUs from Zilog might have a faulty /M1 line ... any inference which requires the /M1 active.[/quote]
... But in my case the M1 line was fine. Multiface 128 ... fine on it and the z80 I replaced worked fine ... between different brands of z80. -
Understanding tape edgesI've never done any tape reading code. But I've read about these "edges" on multiple occasions. Trouble is I don't understand what they heck they are…
... the frequency at which the Z80 reads the input bit (which ... a high frequency signal or a low frequency signal. Which represents " ... turns the input signal into a higher frequency signal whose [i] ... momentary voltage of the input signal. Indeed: [url="https://en. ... -
Correction of +2 hardware errorsThis is a collection of various pieces of information picked up from various places, including a lot from this forum. I have edited it and reworded i…
... of bugs:
- absent input signal RFSH from CPU for eliminate ... also connect RFSH from CPU Z80 to pin 11 of this ... -
Disabling the ROM without removing the whole thingHi! I've got my hands on a non-working issue 6a. I suspect the ROM may be bad, but other things may be faulty as well. I've read that in an otherwis…
... , /WR, /MREQ, /IORQ, /M1 and /RFSH). I was following ... always low? Also, /M1 and /RFSH are always ... those NEC Z80 knockoffs with a bum M1? And shouldn ... chatter between RAM and Z80, which Mark already concluded ... 've already tried removing /M1, /RFSH and /WR from ... -
Disabling the ROM without removing the whole thingHi! I've got my hands on a non-working issue 6a. I suspect the ROM may be bad, but other things may be faulty as well. I've read that in an otherwis…
... logic analyzer to monitor the Z80 clock pin (pin 6) and ... normal functioning of the clock signal to it.
If ... . If either is faulty, the Z80 CPU will not get a ... -
Disabling the ROM without removing the whole thingHi! I've got my hands on a non-working issue 6a. I suspect the ROM may be bad, but other things may be faulty as well. I've read that in an otherwis…
... do see some activity in /M1 and /RFSH. But no matter ... this still point to a Z80 fault?
Thanks ... -
Disabling the ROM without removing the whole thingHi! I've got my hands on a non-working issue 6a. I suspect the ROM may be bad, but other things may be faulty as well. I've read that in an otherwis…
... do see some activity in /M1 and /RFSH. But no matter ... this still point to a Z80 fault?
Thanks
