-
So you need to double (or triple, or quadruple) the clock speed...No particular reason for posting this, other than I was looking at an eZ80 evaluation board that does this, and that jogged my memory of a project I'…
... save them from having to solder things to their Speccy motherboard. So ... 1. So on the low-to-high transition of each flip flop, ... if both flip flops go high at the same time, they ... pretty much to zero by tinkering a bit with the low pass ... -
Difficult to find upper RAM fault.I've recently repaired an issue 3B 48K Spectrum that had a tricky to diagnose upper RAM fault, so I thought I'd post a report of what I found here. …
... POKE to set it to various values and PEEK to see ... all possible RAM addresses, from high to low, writing the decimal value ... each possible RAM location, from low to high, using the HL register ...
I resorted to connecting a logic analyser to the Spectrum's ... -
My attempt to restore the CPU clock signalI know Winston has already got this, but I can't see any thread with details about it. Only wanted to share my (still early) results. I'm not taking…
... details about it. Only wanted to share my (still early) results ... because it would allow us to build things like an external ... it's inverted with respect to the clock input signal.
low level
output wire cpuclk_out ... -
Spectrum audio signallingI've had a poke around in some of the docs (and my Z80 assembler-fu is so rusty it'll be a while before I grok the Complete Spectrum ROM disassembly)…
... (i.e. low to high, and high to low). Is it possible to discriminate between a ... edge? Is it possible to test for the presence or ... the C64 only can see high to low transitions (which was implying ... can at least see both low to high and high to low) - but can it ... -
Question about CP Z80 instructionSorry if this is the wrong folder, but it seems the most appropriate. When performing a CP instruction, is the P flag set when the compared values …
... a,(de) ; fetch high bank
ldi ; move low to high + inc
dec ... hl ; but copy
ld (hl),a ; high to low ... -
Election of the new maintainer of the TZX formatHi folks, the topic says all, let the discussion begin :) Luca
... uses them? Are TZX creators to be to blame? The emulators should ... maybe [i]unknowingly[/i] forget) to include such a HW info ... ? the ZX Spectrum is unable to determine if the edge detected ... port is a transition from low to high, or from high to low, isn't it? -
Election of the new maintainer of the TZX formatHi folks, the topic says all, let the discussion begin :) Luca
... ]unknowingly[/i] forget) to include such a HW info ... creators aren't going to bother testing it. They ... don't have time to test every possible combination ... ZX Spectrum is unable to determine if the edge ... a transition from low to high, or from high to low, isn't it ... -
Election of the new maintainer of the TZX formatHi folks, the topic says all, let the discussion begin :) Luca
... ? Are TZX creators to be to blame? The emulators ... the tape player going to refuse to play the tape? ... up to the emulator to do. If I want to load ... well should be able to without the emulator shouting ... a transition from low to high, or from high to low, isn't it ... -
Fastest Baud Rate On A Loader ?Following on (sort of!) from the thread about the best loading.... Which game(s) had the fastest (highest baud rate) ? I seem to remember a couple …
... socket, but nothing elaborate enough to, say, block an incoming signal ... 't care whether they are high to low or low to high, just so long as ... and expect the standard loader to work. If you understand at ... edge polarities, the time taken to transmit a 1 would be ... -
** Vu-meter competition **Apologies if this is in the wrong section. At the moment, the official number of entries is [COLOR="Red"]0[/COLOR]. :p [B][U]Why?[/U][/B] I was tr…
If you would like me to generate some test tones I ... frequencies, and even maybe some low to high, high to low sweeps.
Let me ... know if you want me to do it and I'll ... -
It's a trap!So I got a CPLD (not the eventual one I want to use for the ethernet project - rather, one I actually have here and now, an XC9536 in a PLCC44). And…
... any CALL instruction to 0x3FF8 to 0x3FFF and then ... when MREQ+RD transition low to high. (M1 is part ... RD+MREQ do a low to high transition, if 0xF8-0xFF ... its outputs will go to high impedance the instant that ... MREQ go high, there output is guaranteed to be what ... -
DRAM (:baffled:)Hi, Can someone explain to me the definitive rules on DRAM access times in terms of suitability for a particular speed of processor? Specifically, …
... a chip go from low to high simultaneously with fast rise ... times. They have to charge up the stray ... if many outputs go low to high at the same time, ... current. This tends to drag the ground above ... and generally cause bad stuff to happen.
... -
Fastest loaderWhat was the fastest speed loader developed and could you name a game using it?
... guaranteed two transitions - low to high, then high to low, for each bit regardless ... this (H means high level, L means low level):
... a low to high transition means 1, and a high to low transition means ... high speed, since I was going to use it to connect to ... -
Fastest loaderWhat was the fastest speed loader developed and could you name a game using it?
... guaranteed two transitions - low to high, then high to low, for each bit regardless ... this (H means high level, L means low level):
... a low to high transition means 1, and a high to low transition means ... high speed, since I was going to use it to connect to ... -
PZX file support for ZX-BlockeditorDear readers, I'm working on the PZX format support for ZX-Blockeditor, as I discovered the advantage of having such a nice file format. It has a cl…
... the pulse sequence to change the signal level from low to high, e.g ... br /> 0 --> high
100 --> low
120*18 --> ... ; low (even means no change)
100*19 --> high (odd ... count)
8655 --> low
735 --> high
I ... -
Multiface 128 Disassembly questionI was looking at a disassembly from a Multiface 128 rom, now I'm not a coder so I have a question, am I correct in understanding the code starts at #…
... (when the M1 line transitions low to high, it reads the address bus ... port's A15 line high so peripherals connected to it which trap ... goes low, i.e. the address bus is guaranteed to be right, to ... , then jumps to 0x0000 this time without holding A15 high, so the ... -
Tape preservation toolsIn the latest MakeTZX thread of doom several people said that it would be good to have active development of tape decoding tools. I needed tape file…
... wishlist topic :) Anyone who wants to can help get Wafadrive emulated ... device that I could use to trivially monitor activity on ... the ROMCS line changes from high to low, or low to high. Of course, I'd ... be very much happy to have ... -
pc keyboard for speccyis it possible to use a ps/2 keyboard for a speccy. I have a +2A, spectrum+ and toastrack, which all have broken keys. So an external keyboard woul…
... caused all keyboard inputs to go low), and put the ... a 8-bit value to output to the CPU (the ... */
PIN 7 = KB2 ; /* KB0 to KB4, keyboard columns */
PIN ... by a WR low to high edge, enabling D4 to enter the ... -
Impossible MissionHello, chaps. Having never played IM before, I gave it a bash last night. Figured out all the panel controls etc, and collected about 10 puzzle pie…
... additional
passwords. Walk up to the console and push the ... will appear. Use the glove to [b]touch each
square ... sorted in ascending order (from low
to high).[/b]
If you ... -
1x XC9572XL or 2x XC9536XL?I'm working on some projects which do not settle with only one XC9536XL CPLD. Main reason is of course the lack of user pins on the XC9536XL, I need …
... (however you might start to run into other resource problems ...
You've also got to consider the cost of PCB ... .
One thing to watch out for is the ... lot of outputs go from low to high at the same time ... (generally it's best to use a 4 layer board ... -
1x XC9572XL or 2x XC9536XL?I'm working on some projects which do not settle with only one XC9536XL CPLD. Main reason is of course the lack of user pins on the XC9536XL, I need …
... lot of outputs go from low to high at the same time you ... applications that operate at relatively low frequencies, there are other techniques ... use the "star-earth" technique to minimise ground bounce.
... routing all around the board to get to a chip.
... -
I'm writing an Operating SystemOkay this might seem like a bait thread, but I am legitamately interested in figuring out how to write a multi-process system for the ZX Spectrum (no…
... the wrapping of the low byte into the high byte.
< ... . Adding 0x102 to it produces 0x0201. The high byte has now ... low bytes, but I think I may have to subtract any high ... would overflow from low to high byte, causing another high-byte change to be detected ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... the results, sort by "Price (Low to High)", and just see what you ... get. Best is to limit yourself to parts that are in ... For any candidate, check datasheet to be sure (for example physical ... postage / minimum order value / minimum # to order etc. always come into ... -
ZXBaremulator 35th anniversary editionHi, to celebrate the 35th Spectrum anniversary, I've released the first complete Spectrum 48K bare-metal emulator for Raspberry PI. It's available…
... question is how to allow the user change from high-to-low-to-high speed. Many ... users, don't want to wait with ... -
ZXBaremulator 35th anniversary editionHi, to celebrate the 35th Spectrum anniversary, I've released the first complete Spectrum 48K bare-metal emulator for Raspberry PI. It's available…
... question is how to allow the user change from high-to-low-to-high speed. Many ... users, don't want to wait with ... , it really brings a lot to the realistic feel of using ... -
Trying to repair a Speccy 48k - No PulsingI've had this machine for ages. I'd I've been putting off fixing it for some time now. So a couple of days ago I pulled it apart and started prob…
... 26) which should be high, but go low to high at power-up, or ... -
Trying to repair a Speccy 48k - No PulsingI've had this machine for ages. I'd I've been putting off fixing it for some time now. So a couple of days ago I pulled it apart and started prob…
... tell the signal starts low, then rises to 5V. Doesn't rise ... . On the scope it seems to take 1/4 second as ... looks to be low, then jumps high.
I can repeat this reset (low to high ... -
ZX Spectrum +3 repairI have my first +3 here, and it needs repairs. Hoping someone here can help me out. When I power it on I get this screen with black and white line…
... signal is ok, goes from low to high.
Clock signal is ok ... lines and data lines seems to be problematic. I have a ... -
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.…
... Kempston needs the signals to go from low to high when pressed; whereas with ... two more ports to a +2 (to add to the two Sinclair ... to make a more compatible version by checking other bits are high ... . Up/Down/Left/Right/Fire are on different bits compared to ...
