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Faulty M1 linesI'm sure this has been discussed before, but using the forum search for the word 'M1' pulled back no hits, which surprised the hell out of me. Anywa…
... detect when an OUT instruction is outputting an I ... and M1 low = an interrupt acknowledge, so just using ... stutters, since the OUT instruction doesn't always cause ... machine cycle of the OUT instruction).
The ... find out whether your Z80 has a faulty M1 ... -
Faulty M1 linesI'm sure this has been discussed before, but using the forum search for the word 'M1' pulled back no hits, which surprised the hell out of me. Anywa…
... low and M1 low = an interrupt acknowledge, so just using IORQ ... movement stutters, since the OUT instruction doesn't always cause an ... machine cycle of the OUT instruction).[/quote]
Hmmm... I ... to find out whether your Z80 has a faulty M1 line ... -
Comments for small "sprite" routine wantedI have just written my first machine code program and I am quite happy (and proud) to get it working! :smile: As a child I never learned anything e…
... they have the complete Z80 manual as a PDF ... want to know about the Z80
[ ... Also see [url]http://www.z80.info[/url] - there's ... quote]
And the HALT instruction, for how long does it ...
Until the next interrupt (either maskable or NMI). That ... -
How does interrupts work?I am a little confused regarding the interrupts on the Spectrum. If I have some hundred bytes of machine code started with, say, [B]RANDOMIZE USR 300…
... , which means when an interrupt occurs the z80 effectively calls address 0x38 ... ) by executing the DI instruction. Another kind of interrupt, known as the ... the keyboard in the interrupt routine. The z80 must scan all keys ... -
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…
... vague hypothesis that the Z80 perhaps samples the IRQ ... Z80 samples the INTREQ during the last cycle of a finishing instruction ... .
[QUOTE]The Z80 is first put under contention ... instruction and then measuring the exact time until the next interrupt ... -
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…
... ) is being lost to the Z80 and it never responds to ... tstates 14335 and 14336 after interrupt do not experience memory contention ... 14337, but if an IO instruction is [B]executing[/B] during ... -
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…
... 0T annotated as start of interrupt signal). He counts everything relative ... with respect to ULA, not Z80.
You and ... last cycle of the finishing instruction, but may be first responded ... - unlike the start of interrupt, the start of INTREQ signal ... -
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…
... oscilloscope hooked up to a Z80 ;-)
[QUOTE ... only tell whether the entire instruction was contended (contended according ... which are contended during the instruction (per given criteria), ... time with respect to the interrupt.
Regards
Input/Output on Edge ConnectorI would like to sense a pulse on the data bus via the edge connector, i.e. on or off. How do you decide what port it is on? I would also like to send…
... the duration of the OUT instruction) all you need is ... it's worth downloading the Z80 User Guide (just google ... for Z80 User Guide, or visit ... all the timings for the Z80, and explain how it ... it, such as raising an interrupt, or setting a flip ...How does the Z80 communicate with hardware?How does the Spectrum (or Z80) interact with other hardware devices? I think devices can communicate with the CPU through interrupts, but how can the…
... IN and OUT instructions. An interrupt would just inform the Spectrum ... disk interface might raise an interrupt when it's ready to ... be read by the Z80, using the IN instruction.
... a device without having the Z80 transfer each byte individually, but ...The direct bus or indirect one... that is the questionThe Ethernet project continues...and I'm in a quandry. So I've managed to implement enough socket library for the W5100 that socket, bind, listen, a…
... . The CPLD will trap the Z80 executing (i.e. MREQ active ... , since the DivIDE traps the interrupt service routine and I'm ... try to execute the first instruction (then set A15 high to ... ISR after handling the W5100 interrupt. I may just have to ...help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... )
The only instruction I don't understand ... contended which means the z80 has to share ... [url]http://www.z80.info/zip/z80-documented.pdf[/url] ... how many cycles an ex instruction takes?[/QUOTE]
interrupt will push things on ...Dangerous Z80 Assembly CommandHave been reading Toni Bakers' "Mastering MC On Ya Speccy" book and came across the list of Z80 commands in the dictionary section. Page 102 "[b]IM…
... contains a chip-music player Z80 subroutine which must be executed ... the foreground, using the HALT instruction, like this month's tape ... />
Any simple IM 2 interrupt routine I write myself (like ... after setting up the IM2 interrupt handler with the chip ...48K games that don't work on a +2Not sure if there is already a thread about this but recently I've noticed some old 48K games will not run on my +2 - even in 48K mode. Examples are…
... Spectrum.
When an interrupt occurred the Z80 would jump to $FFFF ... is the JR instruction opcode).
The Z80 would wrap-around to ... $F3
In short the Z80 would end up at $FFF4 ... .
7) Z80 timing differences. The Z80 in a 128 machine ...RZX Player interface - Possible?If I have a Mass Storage interface and some media (CF, SD) with a couple RZX files, what would I need to play them on a real Spectrum? If the RZX fil…
... /reti combination when (if) the interrupt routine is run so that ... hw doesn't do its interrupt routine. Then when the RZX ... from the data following the interrupt routine for the current frame ... of the instruction count is to delay when the z80 begins executing ...InterruptsI need help emulating interrupts. My z80 core currently emulates all un-prefixed opcodes and the CB opcodes. I thought I would start on emulating co…
... I check for an interrupt after each instruction execution in my main ... .
[quote]When an interrupt occurs, what *actually* happens - i ... ]
[url]http://www.z80.info/zip/z80-interrupts.pdf[/url]InterruptsI need help emulating interrupts. My z80 core currently emulates all un-prefixed opcodes and the CB opcodes. I thought I would start on emulating co…
... interrupting peripheral supplies an instruction on the data bus to ... also be a CALL instruction. Almost no one uses ... cases. Also, since an instruction is executed in the int ... When a maskable interrupt occurs, the z80 automatically disables further maskable ...Playing 128k music with z88dk ?Hi, I'm amazed how easy seems to make things with z88dk to build spectrum asm programs. After my first approach I miss some way to play 128k music, s…
... im2_Init(0xd300); // place z80 in im2 mode with interrupt vector table located ... ); // POKE jump instruction at address 0xd4d4 (interrupt service routine entry)
instruction
#asm
New game: Nanako Descends to HellJust a bit over two weeks after their first game, The Mojon Twins strikes again with a new game for Spectrum 128k and Amstrad CPC: [url]http://www.m…
... /> im2_Init(0xf000); // place z80 in im2 mode with interrupt vector table located ... , 195); // POKE jump instruction at address 0xf1f1 (interrupt service routine entry)
z80 code that can replace the ...Machine Code Routine of the weekHow about a thread that has a routine each week that is in [B]assembly language[/B] and is also described in great detail what the hell is going on …
... s another register on the Z80, the stack pointer ('SP'). ... an interrupt routine is called, or someone uses the CALL instruction, ... the address of the next instruction is pushed ... then the return (RET) instruction actually means 'POP a number ...Program Counter question - please readSorry if this is in the wrong forum, but please read it through anyway - see on the FUSE PSP emulator I asked the author if he'd add an option to pri…
... time the Z80 halts is when it hits a HALT instruction (and ... NOP instructions 'till the next interrupt, it does this so it ... is done once per M1 (instruction fetch) cycle).
... - for example, they have illegal instruction traps, and the MMU can ...Tutorial - learn machine code in 30mins[B][I]Message from the moderators[/I] - bigjon has requested that readers' attention be drawn to a better version of this tutorial, one which is easi…
... comments:
All the z80 registers are 8 bits: A ... , IXL, IXH, IYL, IYH, The z80 architecture allows these 8 bit ... the address of the next instruction), SP (the 16 bit register ... and respond by calling an interrupt service routine. Afterward it will ...Tutorial - learn machine code in 30mins[B][I]Message from the moderators[/I] - bigjon has requested that readers' attention be drawn to a better version of this tutorial, one which is easi…
... watch the iorq pin. z80 instructions that refer to memory ... do this is because the z80 instruction set is much, much richer ... reads the keyboard in the interrupt service routine. If you disbale ... interrupts, the interrupt routine doesn't run and ...Adjusting your code for screen refreshingOk, I'm aware that I should know it already after writing 5 Spectrum games in machine code but interrupts and screen refreshes were always my weaker …
... : will the Interrupt signal that makes a HALT instruction end,
invoke ... ,
as the halting of Z80 clock by the ULA chip ...
screen actions managed by Z80.
This calculation can only ... a rough indication, as the Z80 clock can be
halted ...Memory concerns with z88dkI've retaken my old spectrum project and sadly I've reached a dead end very fast. I'll try to explain my worst problem in a few lines. I'm not a vet…
... is run in an IM2 interrupt routine. The IM2 library can ... /> im2_Init(0xd000); // place z80 in im2 mode with interrupt vector table located ... /> bpoke(0xd1d1, 195); // poke z80 JP instruction
wpoke(0xd1d2, my_isr); // address ...A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
... afford to miss an interrupt pulse. The main program ... page RAM; so will the interrupt routine.
... an atomic operation. The interrupt signal is asserted for ... A useful quirk of the Z80 is that interrupts are ... end of the next instruction after the [b]EI ...A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
IIRC the Z80 will 'remember' internally that # ... your example?).
[*]Have interrupt routine & main program use ... then[/B] do the OUT instruction to actually switch the block ... by block-switching interrupt routine works, and interrupt routine itself doesn ...A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
... next instruction after EI, otherwise if you had an interrupt service ... complete before the next interrupt turned up you'd ... Z80 User Manual gives this as the reason for delaying the interrupt ... until one instruction after EI).A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
... next instruction after EI, otherwise if you had an interrupt ... Z80 User Manual gives this as the reason for delaying the interrupt ... until one instruction after EI).[/QUOTE]< ... loop. By running 1 instruction later (after the RET) ...A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
[QUOTE=RetroTechie;454158]IIRC the Z80 will 'remember' internally that #IORQ ...
Not according to the Z80 User Manual, it doesn't ... any instruction. If a device doesn't want a maskable interrupt to ... apparently being "remembered" on a Z80 based system - it's ...
