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<1234567…34>
  • InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…

    ... after EI. Another point I would make is that the /INT signal must ... first byte of the ROM (DI, 0xf3) would cause a jump ... as the ULA pulled /INT low, the EI will finish 23 tstates ... be disabled ('masked') by the DI instruction, and is always accepted ...
    Fraser Fraser July 2004 Development
  • 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 …

    ... signal that makes a HALT instruction end,
    invoke a MASK-INT ... it to run the MASK-INT routine.
    -------------------------------------------------------------------
    For ... the MASK-INT routine
    DI ;4 nullify the EI inside MASK-INT
    roko roko November 2009 Development
  • 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…

    ...
    [code] org 65000
    di
    ld a,253
    xor a
    ei
    reti

    ... falling edge of the INT signal, the video signal changes its luminance, ...
    mcleod_ideafix mcleod_ideafix December 2011 Hardware
  • InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…

    ... will sample the /INT pin. If /INT is low and ... byte of the ROM (DI, 0xf3) would cause a ... the ULA pulled /INT low, the EI will finish 23 tstates ... finish 27 tstates after /INT went low, and another ... disabled ('masked') by the DI instruction, and is always accepted ...
    Philip Kendall Philip Kendall July 2004 Development
  • 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…

    ... reshaping the ugly shaped clock signal available from the rear bus ... give me a ininterrupted clock signal, filling the gaps where ... />
    From this restored clock signal, it's easier to syntesize ... respect to the clock input signal.

    [code]module ...
    mcleod_ideafix mcleod_ideafix September 2014 Hardware
  • +3 dead(!)Hi, When I turn on my +3 I see only white and black strips (vertical) on screen any idea on how to fix it? Thank you in advance Chris [IMG]http:…

    ... the ROM has executed a DI, then a HALT instruction, so ... ...

    BTW: check the INT signal at Z80. Is it pulsing ...
    mcleod_ideafix mcleod_ideafix September 2009 Hardware
  • 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…

    ... 'remember' internally that #IORQ signal was activated, just not [ ... interrupt only if a DI-period is long enough ... br /> Another reason for keeping DI-periods short is that it ... you don't need DI/EI sequence at all..!! If ... no cycles wasted on DI/EI instructions).
    RetroTechie RetroTechie July 2010 Development
  • Oscilloscope Speccy ProgramHi all, I remember very well in the old days when my Speccy was my single computer (around 1992) that I have had an oscilloscope software. This uses…

    ... real Spectrum was caused by signal peaks causing the loop counter ... by enclosing the loop within DI/EI.
    Battle Bunny Battle Bunny December 2010 Sinclair Miscellaneous
  • yeah - unix for zx spectrumI started a new hobby project. An operating system for ZX Spectrum. A unix clone. Talked to my friend about it and he asked me what if after I'm done…

    ... fine if you're within DI...EI code. but what if ... ). client A controls RTS signal and client B controls CTS ... signal. lets rename these signals ... ) and RTRB. when RTRA signal is 1 then client A ... receive. and when RTRB signal is 1 client B is ...
    tstih tstih April 2011 Development
  • ZX80 and 81 hardware questionsI'm finding a lot of the documentation that is ostensibly about the hardware of the ZX80 and 81 to be primarily about the software. I was hoping some…

    ... on a ZX80:

    DI
    .label JR label
    INT still trigger, with ignoring maskable ... address, meaning that it usurps INT from the Z80's internal ... . So I speculate that the INT signal continues being asserted based on ...
    Thommy Thommy September 2011 Hardware
  • TAP version of CrosswizeIs it possible to create a TAP version of Crosswize with all levels? On the tape or a TZX file, the levels are in the same block and a custom loader …

    ... pages RAM0, sets carry to signal a "good" load and returns ... before loading data, so no di/ei are needed to page RAM ...
    Zup Zup August 2014 Games
  • 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…

    ... commands such as IN, OUT DI, EI and RETN. Trouble is, I ...
    MadDoc MadDoc July 2008 Emulators
  • XPECCY (Lin/Win)im not author of this emulator. Contacts of author you may take on [URL]http://xpeccy.info[/URL] - non official home page. cpu: Z80: all (un)docume…

    ... 1T/4T;
    Screen layout, INT signal, border size, sync signals are ...
    rasmer rasmer November 2014 Emulators
  • converting sna to tapsince i'm struggling to find a simple sna to tap converter that works fine on gnu/linux, i'm about starting to code one on my own (using a scripting …

    ... in the last chunck:
    di
    out 254,bordervalue
    im x
    di/ei
    ld sp,nn
    EI, 0 for DI]
    $14 R
    nitrofurano nitrofurano April 2019 Development
  • 128 Memory PagingI'm having a problem getting my brain around paging. Well, actually the bit I don't understand is how reading I/O ports works! I hope the collective …

    ... /> Yep. Best to wrap a DI/EI around it though :)

    Woody Woody August 2003 Sinclair Basic
  • Any Errors?Any errors you feel Sinclair Research or even Amstrad made with the speccy??

    ... disabled (or 'masked') by the DI instruction. The non-maskable interrupt ... now, isn't affected by DI/EI (or more accurately, the state ...
    Philip Kendall Philip Kendall March 2004 Sinclair Miscellaneous
  • Any Errors?Any errors you feel Sinclair Research or even Amstrad made with the speccy??

    ... disabled (or 'masked') by the DI instruction. The non-maskable interrupt ... now, isn't affected by DI/EI (or more accurately, the state ...
    monty.mole monty.mole March 2004 Sinclair Miscellaneous
  • InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…

    ... as the ULA pulled /INT low, the EI will finish 23 tstates ... after /INT went low. As ... /> [quote]
    tstates after /INT went low, and another interrupt ... the int pulse width, using the smallest interrupt routine possible ("EI;RETI ...
    Alcoholics Anonymous Alcoholics Anonymous July 2004 Development
  • InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…

    ... :
    [quote]
    Unlike the /INT pin, this is edge-triggered ... I gave an address of, /INT is sampled at the leading ... low / high state of the /INT signal that is important at the ...
    Alcoholics Anonymous Alcoholics Anonymous July 2004 Development
  • Will Spectrum run @ 60Hz?Sorry to overlap w/ my other recent post, but want to know, if I grab a Spectrum and use it in America with a voltage converter or a different power …

    ... .5Mhz. The ULA provides the INT signal at 50 beats a second ...
    Geoff Geoff November 2004 Sinclair Miscellaneous
  • Will Spectrum run @ 60Hz?Sorry to overlap w/ my other recent post, but want to know, if I grab a Spectrum and use it in America with a voltage converter or a different power …

    ... .5Mhz. The ULA provides the INT signal at 50 beats a second ... being used as the interupt signal generator.

    EDIT: I ...
    cyborg cyborg November 2004 Sinclair Miscellaneous
  • Will Spectrum run @ 60Hz?Sorry to overlap w/ my other recent post, but want to know, if I grab a Spectrum and use it in America with a voltage converter or a different power …

    ... .5Mhz. The ULA provides the INT signal at 50 beats a second ...
    Alcoholics Anonymous Alcoholics Anonymous November 2004 Sinclair Miscellaneous
  • Interrupt timingsHow long does the ULA hold /INT low for on interrupt on each of the Spectrum models?

    ... various things, we examined the INT signal and I do remember that ... for TTL logic). So the signal has an effective duration which ...
    Luca Luca March 2005 Development
  • Cool BASIC tricks and tips!Following on from Dunny's excellent suggestion of a compendium of BASIC tips + tricks, I believe it would be better to have a topic dedicated to it. …

    [quote]
    On 2005-04-14 16:02, Dunny wrote:
    value from BASIC short of issuing a DI from M/C, reading the bytes and returning the value in BC from an EI.
    [/quote]

    16 bit loads are atomic in m/c -- no need for di/ei
    Alcoholics Anonymous Alcoholics Anonymous April 2005 Sinclair Basic
  • z88dk+splib2 sprites question.I'm creating a game and I have several "states" for my main sprite, such as jump, facing left, facing right, etcetera. All those states require a dif…

    ... to get rid of the di/ei in there so that it ...
    Alcoholics Anonymous Alcoholics Anonymous September 2005 Development
  • z88dk+splib2 sprites question.I'm creating a game and I have several "states" for my main sprite, such as jump, facing left, facing right, etcetera. All those states require a dif…

    ... player code to eliminate every di/ei, otherwise the game went nuts ...
    na_th_an na_th_an September 2005 Development
  • z88dk+splib2 sprites question.I'm creating a game and I have several "states" for my main sprite, such as jump, facing left, facing right, etcetera. All those states require a dif…

    ... player code to eliminate every di/ei, otherwise the game went nuts ... large part because of the di/ei stuff.

    [quote]
    Alcoholics Anonymous Alcoholics Anonymous September 2005 Development
  • RealXThis may be a dumb question but will RealX ever get released?

    ... English), he noticed that the INT signal is asserted by the ULA ... the CPLD to detect the INT duration sometimes as 32T and ...
    Luca Luca August 2006 Emulators
  • How are people developing?Are most coding on actual HW or under emulation, or cross developing?

    ... used this to NOP the DI/EI in the wham! player for ...
    na_th_an na_th_an September 2006 Development
  • Scrolling Loader CounterPlease can someone help me with writing a scrolling counter for a loading system. I like the Hewson counter so i`ve taken the font from zynaps loade…

    ... . I`m wrapping it in DI/EI,RET and assembling to 64000.
    FrankT FrankT November 2006 Development
<1234567…34>

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