While it is easy to create an approximate emulation, the [[Amstrad CPC]] and Plus are very difficult to emulate accurately.
Each chip has its own challenges:
*[[Z80]] is a bloated architecture, with lots of special cases and complex bus logic. The difference with the lean [[GBZ80]] and [[MOS 6502|6502]] is striking.
*[[CRTC]] has a character-based addressing logic, many incompatible chip implementations, and requires accurate VDU emulation too.
*[[Gate Array]] has a weird interrupt system and adds an unnecessary layer of complexity to sync signals.
*[[ASIC]] is buggy and lacks precise documentation.
*[[PAL16L8|Memory management]] is overly complex and limited.
*[[8255|PPI]] has more functionalities than what the CPC needs.
*[[PSG]] cannot be accessed directly as it is behind the PPI. It is simple to emulate though, but it cannot do much.
*[[FDC|765 FDC]] is bloated with 40 pins, compared to 28 pins for the WD1772 FDC used in the [[Atari ST]]. It is also a black box internally, while the [[C64]] uses a regular 6502 (with its own ROM and RAM) as FDC.
And unlike the [[ZX Spectrum]] and the [[MSX]], on the Amstrad CPC and Plus things often go catastrophically wrong if timings are not accurately emulated.
Thankfully, many tools and tests exist to help emulation authors.
= Quick evaluation =
*[https://www.cpc-power.com/index.php?page=detail&num=7529 From Scratch demo] with reference images (CRTC 1): [[Media:From Scratch logo.png]] [[Media:From Scratch tetris.png]] [[Media:From Scratch ovl.png]]
== Diagnostics ==
*[https://auamstrad.es/software/aua-utilidades/ AUA Utilidades] [https://www.cpc-power.com/index.php?page=detail&num=5113 Amstest] [https://www.cpc-power.com/index.php?page=detail&num=17932 Amstrad Diagnostics] [https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/amstrad-diagnostics-rom/msg243665/] [https://www.cpcwiki.eu/forum/software-related/8255-manufacturer-detection/] [https://www.cpc-power.com/index.php?page=detail&num=6545 STS SysInfo] [https://www.cpc-power.com/index.php?page=database&r1=1&lemot=test%20crtc%20v Test CRTC type] [http://quasar.cpcscene.net/doku.php?id=coding:test_crtc] [http://cpc.sylvestre.org/technique/technique_identifier_crtc.html Identifying CRTC visually] [https://www.cpc-power.com/index.php?page=detail&num=11446 Basic Program Status Window] [https://www.cpc-power.com/index.php?page=detail&num=12584 Version du Firmware Basic]
*[http://www.symbos.de/appinfo.htm?00061 SyMon] [http://www.symbos.de/appinfo.htm?00047 HexE] [https://www.cpc-power.com/index.php?page=detail&num=6987 RAM Expansion Test] [https://www.cpc-power.com/index.php?page=detail&num=14833 MemTest] [https://www.cpc-power.com/index.php?page=detail&num=14834 RAM Test CRTC4] [https://www.cpcwiki.eu/forum/technical-support/test-ram-de-mcleod-ideafix/ Test RAM de McLeod Ideafix] [https://www.cpc-power.com/index.php?page=detail&num=15739 RAM Check] [https://www.cpc-power.com/index.php?page=detail&num=13386 Testprogram For All ERAM] [https://www.cpc-power.com/index.php?page=detail&num=16010 Test RAM Basic] [https://www.cpc-power.com/index.php?page=detail&num=19185 Xenon 2] [https://www.cpc-power.com/index.php?page=detail&num=12188 Take On Me] [https://www.cpc-power.com/index.php?page=detail&num=14339 Trololo Experiments] [https://www.cpc-power.com/index.php?page=detail&num=19406 Still The One] [https://www.cpc-power.com/index.php?page=detail&num=16084 Post Scriptum] [https://www.cpc-power.com/index.php?page=detail&num=18658 Onescreen Colonies #2 256K] [https://www.cpc-power.com/index.php?page=detail&num=15985 A tribute to the sisters] [https://amstrad-ggp.itch.io/mightysf Mighty Steel Fighters] [https://cpcrulez.fr/info-chany-enhanced_edition.htm Chany 512K cracks] [https://www.cpc-power.com/index.php?page=detail&num=14814 Anti-Multiface] [https://www.cpc-power.com/cpcarchives/index.php?page=articles&num=151 Expanded RAM software list] RAM exercisers
*[https://www.cpc-power.com/index.php?page=detail&num=15975 FutureOS] [https://www.cpc-power.com/index.php?page=detail&num=4174 CP/M Plus] [https://www.cpcwiki.eu/forum/software-related/what-software-requires-c3-ram-banking/msg246339/#msg246339 Fuzix OS] [https://www.cpc-power.com/index.php?page=detail&num=10030 Phortem] [https://www.cpcwiki.eu/forum/software-related/what-software-requires-c3-ram-banking/msg246582/#msg246582 PhX] [https://www.cpc-power.com/index.php?page=detail&num=19308 DSC4] [https://www.cpc-power.com/index.php?page=detail&num=7270 Pac-Man Emulator] Problematic [[PAL16L8|RAM mode &C3]] on CPC464/664
== Amstrad Plus ==
*[https://www.cpc-power.com/index.php?page=detail&num=9627 Arnold 5 Diagnostic] [https://www.cpc-power.com/index.php?page=detail&num=8838 Cartridge Software Demonstrator] [https://www.cpc-power.com/index.php?page=detail&num=8308 4096 Colors Preview] [https://www.cpc-power.com/index.php?page=detail&num=18998 4096K tester] [[File:Roudoudou CPR tests.zip]] [https://www.cpcwiki.eu/forum/emulators/amstrad-cpc-'acid'-test/75/] [https://www.cpc-power.com/index.php?page=detail&num=3575 No Exit (uninitialised stack pointer)] [https://www.cpc-power.com/index.php?page=detail&num=3580 Pang (RMR2)] [https://www.pouet.net/prod.php?which=103929 3DManiaks 2 (512K)] [https://www.cpc-power.com/index.php?page=detail&num=3576 Tennis Cup 2 (analogue joystick)] Plus testing tools
*[https://www.cpc-power.com/index.php?page=detail&num=7530 Delirium Tremens] [https://www.youtube.com/watch?v=yJcBsQwMzuw Delirium Tremens running on real hardware] [https://www.cpc-power.com/index.php?page=detail&num=18016 Bulles] [https://www.cpc-power.com/index.php?page=detail&num=9169 Funerapolis] [https://www.cpc-power.com/index.php?page=detail&num=7532 X-mas 2008] [https://www.cpc-power.com/index.php?page=detail&num=19239 USS Cygnus 192] To test hardware sprites
*[https://www.cpc-power.com/index.php?page=detail&num=8874 6128 Plus DMA] [https://cpcrulez.fr/demostestDO_fairy-breakpoint_2010.htm Fairy] [https://soundtrackerdma.cpcscene.net/doku.php?id=en:download Soundtracker DMA] To test DMA sound
*[https://www.cpc-power.com/index.php?page=detail&num=12683 Points Barres (Mode 3)] [https://www.cpc-power.com/index.php?page=detail&num=11091 New Mode] [https://www.cpc-power.com/index.php?page=detail&num=12905 "Mode 5" Viewer] [https://www.cpc-power.com/index.php?page=detail&num=19220 Raster Slideshow] [https://www.cpc-power.com/index.php?page=detail&num=16075 Brutal Deluxe] [https://www.cpc-power.com/index.php?page=detail&num=12528 Rhino-Raster] [https://www.cpc-power.com/index.php?page=detail&num=16466 Split-Rasters Test CRTC1] [https://www.cpc-power.com/index.php?page=detail&num=491 Crazy Ball] [https://www.cpc-power.com/index.php?page=detail&num=2280 Trailblazer] [https://www.cpc-power.com/index.php?page=detail&num=931 Fugitif] [https://www.cpc-power.com/index.php?page=detail&num=3963 Sudoku Master] [https://www.cpc-power.com/index.php?page=detail&num=18626 Flush Wishes You a Happy New Year] [https://www.cpc-power.com/index.php?page=detail&num=18680 Pixel Free] [https://www.cpc-power.com/index.php?page=detail&num=11825 Overscan Megatext] [https://www.cpc-power.com/index.php?page=detail&num=14763 Gozeur Intro 2] [https://www.cpc-power.com/index.php?page=detail&num=13136 Interlace viewer] [https://www.cpc-power.com/index.php?page=detail&num=9564 Interlaced 800x600] [https://www.cpc-power.com/index.php?page=detail&num=7396 Interlace] [https://www.cpc-power.com/index.php?page=detail&num=7701 Climax] [https://www.cpc-power.com/index.php?page=detail&num=9160 Kvety] [https://www.cpc-power.com/index.php?page=detail&num=19347 Flipraster] [https://www.cpc-power.com/index.php?page=detail&num=13139 Perfect Pix Paint] [https://www.cpc-power.com/index.php?page=detail&num=12030 Bat-Moule] [https://www.cpc-power.com/index.php?page=detail&num=17706 Tetris] [https://www.cpc-power.com/index.php?page=detail&num=13359 Imperial Mahjong] Special graphics modes [http://cpc.sylvestre.org/articles/articles_imperial_mahjong.html Mode EGX] [[Mode R]] [https://code.google.com/archive/p/grafx2/issues/342 Mode 5] Technical explanations
*[https://www.cpc-power.com/index.php?page=detail&num=16027 Mire] [https://www.cpc-power.com/index.php?page=detail&num=8257 Chany Dream 5] [https://www.cpc-power.com/index.php?page=detail&num=8307 4 Sins] [https://www.cpc-power.com/index.php?page=detail&num=11820 TV Noise] [https://www.cpc-power.com/index.php?page=detail&num=7826 Climax-G] [https://www.cpc-power.com/index.php?page=detail&num=8395 Nice Picture Show] [https://www.cpc-power.com/index.php?page=detail&num=7937 Fatal Beauties] [https://www.cpc-power.com/index.php?page=detail&num=9090 JavaCPC Overscan] [https://www.cpc-power.com/index.php?page=database&r1=1&lemot=pixel%nation Pixel Nation] [https://www.cpc-power.com/index.php?page=detail&num=7897 Twinblast] [https://www.cpc-power.com/index.php?page=detail&num=8081 MCS 6] [https://www.cpc-power.com/index.php?page=detail&num=7593 Schadel] [https://www.cpc-power.com/index.php?page=detail&num=7451 Scandinavian Flag] [https://www.cpc-power.com/index.php?page=detail&num=7858 Kill JLCS] [https://www.cpc-power.com/index.php?page=detail&num=15705 Deleting Disc] [https://www.cpc-power.com/index.php?page=detail&num=9085 Plasma Pas Cher] [https://www.cpc-power.com/index.php?page=detail&num=13528 Wavy] [https://www.cpc-power.com/index.php?page=detail&num=14778 Vagues sur l'écran] [https://www.cpc-power.com/index.php?page=detail&num=18654 Bildschirmverzerrer] [https://www.cpc-power.com/index.php?page=detail&num=2224 Thunder Blade (292 lines)] [https://www.cpc-power.com/index.php?page=detail&num=454 Bonanza Bros (295 lines)] [https://www.cpc-power.com/index.php?page=detail&num=2318 Turrican (296 lines)] [https://www.cpc-power.com/index.php?page=detail&num=102 Wonder Boy (296 lines)] [https://www.cpc-power.com/index.php?page=detail&num=1960 Sliders (330 lines)] [https://www.cpc-power.com/index.php?page=detail&num=1763 Rastan (336 lines)] [https://www.gamopat-forum.com/t122994p900-amstrad-cpc-topic-officiel Bomb Jack remake (over-overscan)] To test the VDU
*[https://www.cpcwiki.eu/forum/games/street-fighter-ii-cpc/msg248822/#msg248822 Street Fighter II proto (crtc0)] [https://www.cpc-power.com/index.php?page=detail&num=1546 Octoplex (crtc1)] [https://www.cpc-power.com/index.php?page=detail&num=781 Dynamic Duo (crtc1)] [https://www.cpc-power.com/index.php?page=detail&num=818 Druid II (crtc1)] [https://www.cpc-power.com/index.php?page=detail&num=15672 Legend of Steel (crtc1)] [https://blogwww.logonsystemcpcwiki.eu/compendiumforum/ 007 programming/the-living-daylights-extra-colours-in-mode-1-rasters-screen-splits/msg249849/#msg249849 The Living Daylights (crtc1)] [https://forum.system-cfg.com/viewtopic.php?p=234421#p234421 FMR (crtc1)] Some known bugs on real CRTCs
*[https://www.cpc-power.com/index.php?page=detail&num=8615 Welcom-X 2 (crtc0)] [https://www.cpc-power.com/index.php?page=detail&num=7479 Madness (crtc1)] [https://www.cpc-power.com/index.php?page=detail&num=7561 5KB 1 (crtc1)] [https://www.cpc-power.com/index.php?page=detail&num=9102 Scrolling Hard Vertical (crtc2)] Some programs that only run correctly on one type of CRTC
*[https://www.cpc-power.com/index.php?page=detail&num=41 Trantor] [https://www.cpc-power.com/index.php?page=detail&num=204 3D Starfighter] [https://www.cpc-power.com/index.php?page=detail&num=726 Treasure Island Dizzy] [https://www.cpc-power.com/index.php?page=detail&num=971 Ghost Hunters] [https://www.cpc-power.com/index.php?page=detail&num=2132 Super Robin Hood] [https://www.cpc-power.com/index.php?page=detail&num=237 Advanced Pinball Simulator] [https://www.cpc-power.com/index.php?page=detail&num=1200 Jet Bike Simulator] [https://www.cpc-power.com/index.php?page=detail&num=1002 Grand Prix Simulator] [https://www.cpc-power.com/index.php?page=detail&num=183 Darts 180] [https://www.cpc-power.com/index.php?page=detail&num=1243 Killapede] [https://www.cpc-power.com/index.php?page=detail&num=7210 Startest] [https://www.cpc-power.com/index.php?page=detail&num=1194 Jail Break] [https://www.cpc-power.com/index.php?page=detail&num=1815 Robocop] [https://www.cpc-power.com/index.php?page=detail&num=100 Chase HQ] [https://www.cpc-power.com/index.php?page=detail&num=1926 Shinobi] [https://www.cpc-power.com/index.php?page=detail&num=895 Fly Spy] [https://www.cpc-power.com/index.php?page=detail&num=1388 Meltdown] [https://www.cpc-power.com/index.php?page=detail&num=17788 Throne Legacy] [https://www.cpc-power.com/index.php?page=detail&num=19569 Léon Marchand's Olympic Challenge] [https://www.cpc-power.com/index.php?page=detail&num=17587 Just Get 9] [https://www.cpc-power.com/index.php?page=detail&num=8892 4-Bit Digi Try] [https://www.cpc-power.com/index.php?page=detail&num=8580 OctoBear] [https://www.cpc-power.com/index.php?page=detail&num=4372 Speech] Software English vocal sounds
*[https://www.cpc-power.com/index.php?page=detail&num=814 El Enigma de Aceps] [https://www.cpc-power.com/index.php?page=detail&num=1349 Le Manoir de Mortvielle] [https://www.cpc-power.com/index.php?page=detail&num=286 Etrange Castel] [https://www.cpc-power.com/index.php?page=detail&num=910 Forteresse] [https://www.cpc-power.com/index.php?page=detail&num=511 Canadair] [https://www.cpc-power.com/index.php?page=detail&num=1140 L'île] [https://www.cpc-power.com/index.php?page=detail&num=1199 Jaws] [https://www.cpc-power.com/index.php?page=detail&num=1102 Holocauste] [https://www.cpc-power.com/index.php?page=detail&num=284 Apocalypse] [https://www.cpc-power.com/index.php?page=detail&num=1722 Punk Star] [https://www.cpc-power.com/index.php?page=detail&num=132 Afteroids] [https://www.cpc-power.com/index.php?page=detail&num=274 Amstroids] [https://www.cpc-power.com/index.php?page=detail&num=1098 Hold-Up] [https://www.cpc-power.com/index.php?page=detail&num=879 Fire & Forget] [https://www.cpc-power.com/index.php?page=detail&num=1433 Xyphoes Fantasy] [https://www.cpc-power.com/index.php?page=detail&num=5088 Spectra] [https://www.cpc-power.com/index.php?page=detail&num=17000 Space Race] [https://www.cpc-power.com/index.php?page=detail&num=7456 Yao demo] [https://www.cpc-power.com/index.php?page=detail&num=8311 Terrific] [https://www.cpc-power.com/index.php?page=detail&num=7548 Face Hugger Ultimate] [https://www.cpc-power.com/index.php?page=detail&num=7415 Smallest Scroll] [https://www.cpc-power.com/index.php?page=detail&num=14765 Xenon] [https://www.cpc-power.com/index.php?page=detail&num=17542 Musik100] [https://www.cpc-power.com/index.php?page=detail&num=15311 Digital Synthesizer] [https://www.cpc-power.com/index.php?page=detail&num=5031 Echosoft] [https://www.cpc-power.com/index.php?page=detail&num=4735 Mega Sound] [https://www.cpc-power.com/index.php?page=database&lemot=digitracker&compagnie=906 Digitracker NGS] Other software sound effects [https://www.cpc-power.com/index.php?page=database&audiotape=1 Audio-tape included software list]
*[https://www.cpc-power.com/index.php?page=detail&num=17913 RUN!] [https://www.cpc-power.com/index.php?page=detail&num=9179 Now that's what I call Chip Tunes] [https://www.cpc-power.com/index.php?page=detaildatabase&numlemot=18904 amstream Amstream music-diskAutomated Music Player] [https://www.cpc-power.com/index.php?page=detail&num=10467 We Are All Old] [https://www.cpc-power.com/index.php?page=detail&num=7700 Anthology] [https://www.cpc-power.com/index.php?page=database&lemot=ayc%20sound AYC Sound] [https://www.cpc-power.com/index.php?page=database&lemot=shap%20audio Shap Audio] [https://www.cpc-power.com/index.php?page=detail&num=18997 Amstrad CPC Mix] [https://www.youtube.com/@hermol2903/playlists YM!Rulez (real hardware recordings)] [https://www.cpc-power.com/index.php?page=detail&num=9734 Soundtrakker 128k] [https://www.cpc-power.com/index.php?page=detail&num=11771 ST128 Song Modules by BSC] [https://www.cpc-power.com/index.php?page=detail&num=17447 Starkos] [https://www.cpc-power.com/index.php?page=detail&num=11770 Starkos Song Modules] [https://www.cpc-power.com/index.php?page=detail&num=6266 Ams'Orgue] [https://www.cpc-power.com/index.php?page=detail&num=18265 Sintetizador de Sonidos] To test the PSG emulation
<br>
*[https://framagit.org/shinra/vgmplay VGMplay] [http://www.roudoudou.com/ACE-DL/ OPL3 VGM pack] [https://drive.google.com/drive/folders/1o1KKHB4rzLe324VmfAEhzJt-zb7IS5bI SID Player] [https://www.cpc-power.com/index.php?page=detail&num=4682 MidiTrack Performer] To test [[Willy|Willy OPL3]], [https://youtu.be/_LWbnjvXN4g RSF3 SID] and [[EMR MIDI Interface]] ([https://youtu.be/YOjV9AaIVKM RSF3]) soundcards emulation
*[https://www.cpc-power.com/index.php?page=database&lemot=hardware_phaser_loriciels West Phaser] [https://www.cpc-power.com/index.php?page=database&lemot=hardware_gunstick Gunstick] [https://www.cpc-power.com/index.php?page=detail&num=4303 Trojan LP-1] To test lightguns and lightpens connected to joystick port [https://www.cpc-power.com/index.php?page=database&lemot=hardware_magnum Magnum Light Phaser] [https://www.cpc-power.com/index.php?page=detail&num=3583 SkeetShoot] [https://www.cpc-power.com/index.php?page=detail&num=3584 The Enforcer] [https://www.cpc-power.com/index.php?page=detail&num=3992 Dk'Tronics Light Pen] [https://www.cpc-power.com/index.php?page=detail&num=4955 Light Pen Mark II] [https://www.cpc-power.com/index.php?page=detail&num=5853 Dart Light Pen] [https://www.cpc-power.com/index.php?page=detail&num=15975 FutureOS] To test lightguns and lightpens connected to expansion port
*[https://www.cpc-power.com/index.php?page=detail&num=19482 The Key] [https://www.cpc-power.com/index.php?page=detail&num=1349 Le Manoir de Mortvielle] [https://www.cpc-power.com/index.php?page=detail&num=11808 Pro-Design] [https://www.cpc-power.com/index.php?page=detail&num=5039 Cherry Paint] [https://www.cpc-power.com/index.php?page=detail&num=5348 EasiArt] [https://www.cpc-power.com/index.php?page=detail&num=4291 GPaint] [https://www.cpc-power.com/index.php?page=detail&num=4286 AMX Art] [https://www.cpc-power.com/index.php?page=detail&num=4012 Advanced OCP Art Studio] [https://www.cpc-power.com/index.php?page=detail&num=6351 Max Desktop] [https://www.cpc-power.com/index.php?page=detail&num=5208 Worktop] [https://www.cpc-power.com/index.php?page=detail&num=4733 DES] [[Stream2]] [https://www.cpc-power.com/index.php?page=detail&num=15975 FutureOS] [[SymbOS|SymbOS (AMX and Albireo mice)]] To test [[AMX Mouse]] and [[Albireo|Albireo USB mouse]] emulation*[https://www.cpc-power.com/index.php?page=detail&num=4026 Tasword] [https://www.cpc-power.com/index.php?page=detail&num=4028 Tasprint] [https://www.cpc-power.com/index.php?page=detail&num=4672 Print Master] [https://www.cpc-power.com/index.php?page=detail&num=12589 ProText] [https://www.cpc-power.com/index.php?page=detail&num=9583 ProType] [https://www.cpc-power.com/index.php?page=detail&num=4668 ProPrint] [https://www.cpc-power.com/index.php?page=detail&num=12745 Miraprint] [https://www.cpc-power.com/index.php?page=detail&num=4666 Qualitas Plus] [https://www.cpc-power.com/index.php?page=detail&num=4516 BrunWord] [https://www.cpc-power.com/index.php?page=detail&num=5212 CPC-Word] [https://www.cpc-power.com/index.php?page=detail&num=4104 MicroDesign] [https://www.cpc-power.com/index.php?page=detail&num=15528 Page Printer] [https://www.cpc-power.com/index.php?page=detail&num=4657 Stop Press (AMX Pagemaker)] [https://www.cpc-power.com/index.php?page=detail&num=5315 X-Press] [https://www.cpc-power.com/index.php?page=detail&num=10004 Page Publisher] [https://www.cpc-power.com/index.php?page=detail&num=5204 PowerPage 128] [https://www.cpc-power.com/index.php?page=detail&num=14009 Page Setter 64] [https://www.cpc-power.com/index.php?page=detail&num=12116 StarMouse] [https://www.cpc-power.com/index.php?page=detail&num=5551 Impr'Image] [https://www.cpc-power.com/index.php?page=detail&num=6127 Speedtrans screen dump] [https://www.cpc-power.com/index.php?page=detail&num=17613 Kdump] [https://www.cpc-power.com/index.php?page=detail&num=4016 Printer Pac II] [https://www.cpc-power.com/index.php?page=detail&num=5712 Impression] [https://www.cpc-power.com/index.php?page=detail&num=5576 RSX Imprimante] [https://www.cpc-power.com/index.php?page=detail&num=5157 Scrypte] [https://www.cpc-power.com/index.php?page=detail&num=6287 Machine à écrire] [https://www.cpc-power.com/index.php?page=detail&num=5883 DemoImp] [http://www.symbos.de/appinfo.htm?00069 PrintIt] [http://www.symbos.de/appinfo.htm?00066 Wordpad] To test printer emulation*[[HDCPM]] [https://www.cpc-power.com/index.php?page=detail&num=15975 FutureOS] [http://www.roudoudou.com/ACE-DL/ SymbOS] [[UniDOS]] [http://amsnet.chez.com/ UniLoad] [https://mega.nz/folder/93pR2KiA#qlkiFakrZhSzmko65EbTWw/folder/pmpEiYBZ LiliCPC] [https://cpcrulez.fr/applications_disc-m4_front-end.htm M4FE] To test RTC and mass-storage emulation
*[https://cpcrulez.fr/applications_util-rulez-change-m4wifi.htm RulezCharge] [https://www.cpc-power.com/index.php?page=detail&num=16746 CPChessNet] [https://github.com/fergusleen/m4ewenterm Ewen] [https://www.github.com/salafek/KCNet-software-for-Net4CPC KCNet utilities] [http://www.symbos.de/appinfo.htm?00017 NsLookUp] [http://www.symbos.de/appinfo.htm?00020 SymTel] [http://www.symbos.de/appinfo.htm?00019 WGet] [http://www.symbos.de/ SymbOS] [[UniDOS]] To test the network emulation
*[https://www.cpc-power.com/index.php?page=detail&num=12972 X-MEM FW] [https://www.cpc-power.com/index.php?page=detail&num=9866 32 Roms Booster] [https://www.cpc-power.com/index.php?page=detail&num=10969 Roman] [https://www.cpc-power.com/index.php?page=detail&num=19236 CatRun] [https://www.cpc-power.com/index.php?page=detail&num=18901 CowSay] [http://impdraw.wikidot.com iMPdraw] [http://imptiles.wikidot.com/ iMPtiles] [https://www.cpc-power.com/index.php?page=detail&num=4008 Graph'OS] [https://www.cpc-power.com/index.php?page=detail&num=6129 Nirvana] [https://www.cpc-power.com/index.php?page=detail&num=6353 Utopia] [[Hexam]] [https://www.cpc-power.com/index.php?page=detail&num=12552 Orgams] [https://cpcrulez.fr/applications_disc-yet_another_norton-commander_clone.htm YANCC] [[HDCPM]] [https://www.cpc-power.com/index.php?page=detail&num=15975 FutureOS] [http://www.symbos.de/ SymbOS] [[UniDOS]] [https://archive.org/details/cpc-roms ROM Games] To test ROMboard emulation
The way to cause the RAM refresh to fail in both a Plus or normal CPC is simply to stop a few bits of the CRTC address changing (ie. never refresh the selected area).
Generally, only the Row address needs to be cycled, so stopping MA0 through MA7 from changing, and stopping the CPU from reading those rows, will cause data to be lost, quite quickly (generally around 4ms).
*Detecting corruption in the PSG registers when a register write is not validated. [https://www.cpcwiki.eu/forum/programming/interesting-walkthrough-video-coding-a-pet-to-play-samples-at-60khz/msg250874/#msg250874 Source]
*Playing with the "floating" bus. Using Z80 read I/O commands to write to chip registers. Accessing ghost registers. Using undocumented I/O ports. Writing to multiple chips simultaneously. Changing PPI and PSG ports direction.
*Focusing on the minute details in [[Z80]], [[CRTC]], [[8255|PPI]] and [[PAL16L8|PAL]] chips. They are most often wrong in emulators.