One clarification: At around 15:00 I simplify things quite a bit by saying the address bus determines who that data is intended for. I left out the part that in the case of a Z80 like we have here, there are also control signals that come into play (/MEMRQ and /IORQ) that determine if the data is intended for the RAM or another chip. There are other architectures that have memory-mapped I/O where the control signals aren't necessary and a specific address is all is needed to target a particular chip.

I had the Schneider CPC-464 (German version) and a flight simulation game simulating an Apache Tomcat helicopter. It had a copy protection - it displayed a pixel pile and one had to use a foldable plastic lens positioned at some marks to read a code that was hidden in the garbled pixels. No matter how I tried, I got the digits wrong in 8 out of 10 cases. That's why I bought the Multiface II - once I had over one the code deciphering hurdle successfully, I saved the game right there, and from then on I was able to fire up the game and play without that endless annoyance. These were the times ...

I believe the most underrated part is the explanation of how the data/address bus work! I will be constantly referring this to people who want a simple and straight forward explanation about that subject. It was brilliant!

I have a similar story. I had the Commodore 64 and did exactly the same thing as you, reverse-engineering the code to add infinite lives and stuff like that. I also converted a lot of cassette games to load from the disk drive, adding a small turbo loader to speed things up a bit. This taught me so much about 6502 assembly and also about the Commodore 64 and Disk Drive hardware and memory mapping as well. Good times, I remember them with fondness. By the way this multiface is very similar to the Action Replay and Final Cartridge versions that we had for the Commodore 64. Great Video ;)

Noel. You are a true genius in everything you do and how you explain it brilliantly. I have no background in electronics except what I learned myself over the years. My background is industrial automation making today's industrial world more efficient but my love is old stuff. So we'll designed and thought out with what they had. I have bought and repaired vintage amplifiers, twin cassette decks that I now listen to. Long story short I bought 4 items on ebay untested of course. 2 Atari's 2600, both fixed. A commodore 64 PSU issue so today I rebuild a new PSU by hammer and punch literally breaking open a brick of death to get the 9 volt ac transformer and rigged a 5 volt switching charger to the din power plug for the 64 and working perfectly. My problem is my last one an Amstrad cpc 464. Anytime I power it on I get zig zag, horizontal lines but most frequently white screen black border. I have schematics but I work with a magnifying glass a digital multimeter and a hunger to know why and what am I missing. Any ideas and how did you learn all this? Life I know but books, college etc I would be extremely grateful for any information. Best on KZfaq without a shadow of a doubt. Keep posting.

What a brilliant video about the multiface 2 Noel, thank you for doing this ! you are a star :)

This is the first thing I ever saved up for. 4-5 weeks doing two paper rounds. It was brilliant (I sold a whole load of CPC stuff 4 years ago when I moved.... There were three of them in the box!)

Thank you for the video and all the explanations. I have the Multiface original one, but I havent explored all the options until now.

I was so pleased with the Multiface One for my ZX Spectrum. At the time it was like a little piece of boxed up magic.

Excellent explanation of how the device works. Great video! Your proposed new device would be very useful for those with busy lives, allowing them to stop and restart their gaming with little lost time.

Nice clean build and some great technical information shared there, Noel. Skills acknowledged. Glad you finally got your Multiface II! I had an Action Replay on my Amiga and loved it. Had no clue what this was in my Amstrad days but it would have been a hoot.

Great video and walk through, thanks for sharing

Absolutely brilliant video. Great explanation and the info on the “arms race” was very entertaining. Subbed and hit the bell!

A college friend of mine and a partner designed a board, which did exactly the same thing for the Apple II, which would have been around 1979-80 from memory. They set up a company and sold huge numbers, mostly in the USA and for a few years it made quite a lot of money. There were attempts by software companies to stop the sale of these type of devices, as they were widely used to bypass copy protection, but they all failed as (officially at least), they were sold as ways of making legitimate backups of software. So, these sort of boards were around for some years earlier, albeit for different machines.

I hadn't seen anybody using a rag over the board when you are using IPA, to clean the flux and then using the tooth brush over it. I was always having problems to clean the flux and your method seems to work perfectly well.

Takes me back, i still got the two Multiface's i bought in the original packaging. 1 for my Spectrum 128k and a Multiface for my Spectrum +3. So great

Awesome ! Great video Noel !

Great video. I always wanted one of these just for the snaps, now with the M4 I'm fine :-)

Amazing video. I was cracki g games for the c64 back in the day, but I used an action replay mk5 to be able to debug the code and remove copy protection. This did not stop me from learning, because saving a freeze file was considered lame. So the main use for the action replay in this regard was to set a breakpoint on the loading routine, so that we could save the memory before a game would start. Porting multi level cassette games to disk by saving each chunk of level data and by rewriting the loading routines in the main game was fun too. 😁

This device was a godsend back in the day. Copying tape games onto disc saved so much time!

I used to borrow my friends Muliface 128 for the Speccy in the 80's so I could transfer my games to Microdrives. Last year I found that a Muliface 128 clone had been made. (Probebly the same people that made yours). So now I have my own. Yipee. :)

I still have mine! I loved looking at the HEX code looking for messages from the programmers

I remember a friend of mine back in the day had the MF and was using it mostly for copying games, and what a coinsidence to pause HOH, like in this video. I remember begging him for several days to borrow the device for testing, which I got, only to discover that in real world senariors most users wouldn't bother that much about the "pause and save state" memory dump feature but rather for the other major benefit of removing copy protection and transfering software from tapes to disk which did require specific skills that n00bs didn't have. Most of them just wanted to copy and trade games with each other. That was actually my first "gig" in the IT sector back in the '80s as a teenager and let me tell ya, making the equivalent of an adult's salary with minimal effort, was an incredible thing. I was already writing code and even made 3 game clones (pacman, donkey kong, snake) and also messed around with a type of quasi-hardware sprites that were theoretically impossible on the CPC, but it was that period that I got my first serious experience of learning both about hardware and software (albeit I started with a C64 before the Amstrad CPC). Although "technically" illegal in today's terms, it gave me a glimpse of how much money could be made in the computer sector, and after that I never looked back. Over the years I got degrees in programming and design and had multiple careers as IT technician, CG artist, web developer and even got some inventions. Now as far as the Multiface goes, because Discology and Pyradev were able to do the "other half" of MF's major features and there was no need for extra hardware, MF was not as popular as most people think. In fact its because of those abilities especially in Discology, that it became THE software to own for the CPC. I almost made a living because of that thing for several months at the age of 14, providing "reverse backup services" *wink wink* to people that had tons of software on tapes, and paid good money to transfer them to floppy disks. In "partnership" with 2 local computer stores I made the equivalent of 200 euros per week (in todays money adjusted for inflation -- that's a full time salary) and for a teenager of the '80s such easy cash made me feel like I've cleaned up a Casino or something. LOL! So thank you Noel for brining back those "memories" - no pun intended ;-)

You might describe the technique whereby I/O write data is stored on the Multiface II as "bus snooping". That's a term normally applied to caches, but I think it could apply here as well.

Some additional details. The filtering of the I / O addresses of multiface 2 is much more precise than that of the circuits. Thus, only bit 14 of the address (= 0) is enough to access the CRTC, whatever the value of the other bits 10111100xxxxxxxx = BCxx. Bits 10, 11, 12, 13 and 15, when set to 0, allow access to the other circuits. (Say otherwise it's possible to address several circuits simultaneously) So instead of using BC to access the CRTC, you can also use 00111100 = 3C. One of the many ways to crash a program saved by the multiface is to set all the CRTC registers to 0 on the BC port, and set the normal values ​​with 3C. So when the multiface wants to reset the values ​​to their correct values, it crashes the machine. It is much simpler than trying to detect the card. I no longer remember if the interface correctly manages the return address from the interrupt when Z80A Stack Pointer register is located between 0000 and 3FFF when the button is pressed. It would be also interesting to know how the multiface detects what is the interruption mode of the Z80A when the button is pressed.

This is amazing! Thank you so much! I came here, because I found out that WinAPE allows to attach a Multiface II ROM. Now I know how it feels like, because I never had one. And naturally many ideas come up: Is it possible to dump my favorite game at a certain level and then transfer it to my real 464? Yes, but you need something like Anti-Multiface which allows to restore a backup without a Multiface present, but Anti-Multiface requires 128kB, but then I found MF2RR which works with 64kB! Hilarious! I tested it successfully!

Wow ! Thank you very much, awesome review ! I'm a big fan of Amstrad, when I was young I spent lot of time to hack some games or to understand how to do.. But no google at this time so no way... I always wanted one of these interface but in 1988 that was no easy to get one... Thanks agains very nice video

I'm already hooked to your videos. By the way, would you be interested in inspecting a SNES that freezes while playing Sensible Soccer (maybe its the game cart) or is that outside the scope of your Retro Lab?

I'm a Commodore 64 guy, but watching your videos makes me want to get a CPC.

I used to have an Action Replay, a similar device for the C64. Great little piece of hardware. I used to use it to copy my own tape games to other tapes, I didn't own a disk drive, as the turbo tape loader was much faster. You could get a game that would take around 100 on the tape counter down to 60 or even less in some cases. On a C60 you could get 5 or 6 games per side, if I remember rightly, and I'd put my original copies away and just use the fast loader. Since you could save where you like, you could just bypass any code style copy protection with ease. The big issue is that it didn't work on multiload games, for obvious reasons.

I have a Action Replay III for my Amiga A500. I used it for copying disks and helping in games etc.

Noel, the M4 card has something called hack menu that makes more or less the same thing

I wanted one for my CPC 464+ SO BAD back in the day! The closest I ever got was having a multiface 1 on my speccy, I could pause and look at code, even save the entire contents of the RAM on to tape and so if I was playing a game I could just save it and then load it back again later and pick up from where I left off.

Most likely two transistors in case you don’t read the instructions about the mistake and put it in the wrong way around. So in the case you can cut the old one out, which is a lot easier than de-soldering if you don’t have the correct tools.

That little note "the Multiface II+ must be present, so pirates will find this about as much use as a rubber cutlass." Sure, unless everyone has one. I can imagine this was great for kids who only got to play a limited time from their parents, meaning they could actually play the whole game instead of just repeat the first levels.

Looking to buy / build one of these. The retro forum is in Spanish, and Rewinding has PM's disabled at the moment. There is apparently an interest list for the MX4 version, and more boards getting made up for the Edge version

I had two Action Replays for the Amiga. Had no too much clue how to really utilize it but nevertheless it was a nice and useful device.

Hello @NoelsRetroLab . Do you know where MF2 can be bought as DIY kit? Preferably in the EU. Help appreciated!

Great video and super interesting. I was just thinking how cool it would be to have something similar for game consoles like the NES, or have a modern version of the Multiface that can save to SD card as well as floppy. Thanks for the great video!

I still have my multiface 128 for the zx spectrum 48/128, same ideas, i also reverse engineered the logic for fun lol. I hacked mine to allow me to save to the Mgt disk drive interface using the Disciple save option and a hardware mod. Well hackable, shadowed ram on top of the rom so i could use the whole interface as the spectrum rom. All of this was done when i was about 20 years old, 30 years later and i still have everything, but the p.c is my running computer now.

funny thing is , romantic robot owner is only up the road from me in London. not sure if he's still about as he's rather old now.

Would it be feasible to make a Multiface Pi? Then it might open up the possibilities to get WiFi, save games and load programs over WiFi, or to SD, use the Pi CPU as a coprosessor, or use the RAM as a RAM expansion, etc. Endless possibilities from just one little Raspberry and some glue logic. Maybe?

1:26 did I just see an ad for an SSD? the silicon disk

Hello! I own a multiface 2. Quick question. When I press stop button, the games pauses but I do not get the multiface's options! What could it be wrong? Reset button works fine in terms of restarting. Thank you in advance.

Hello i would like to buy this kit, but i didn't find any more. Has someone a shopping link adress for buying the kit ?

Does anybody know where i can buy a kit or a link to the pcb design for PCBWay please.

Do you make a multiface 2 for others and if so at what price?

Has an Invisible mode. Ie The Race won’t load properly if plugged in, however, press the red button and then R and now the MF2 is Invisible. :) There is also a program called Insider that works with the MF2. F11 in WinAPE. Reset Ctrl F9. Love WinAPE! :)

That looks a nice tool. Almost I want to buy it, just... It seems to requires a disk driver and I have the same CPC464 that you show behind you :) Is that right?. By the way... very handful video as usual from you Noel. :) See you in the next video.

So this is the predecessor of the AMIGA Action Repla,ykind off? AIMGA 4 EVER :) !!! Cheers.

Always wanted one shame the forum is in Spanish is there a english link?

The board design didn’t have decoupling capacitors. That’s kind of a big no no, especially on a reengineered design. However is not all doom and gloom, one can just tack the capacitors to the underside of the board

Urgh. The memories of the Spectrum Multiface. M128 LOADING For ages. The bootloader and the three CODE sections, with that blue and yellow message flashing away. M128 LOADING. For the same length of time for every game, being a memory dump. Waiting for it to load. M128 LOADING. Then,you think you are there. It's over. M128 not loading any more. You made it. R Tape loading error 0:1

Just curious: you didn't explain the function of the DIP switches...

what are these Ahms you keep talking about?

You can use emulators to save a modern snapshot or on hardware use the board you just soldered together. Why would there be a need for another "modern" version that is not a Multiface?

What is needed is something to convert and buffer lets say a +D floppy interface to a hard drive !

so basic compared to similar tools on C64 but I love this kind of devices! EDIT: I see that the task of this cartridge is much more complicated because of the architecture of the Atari. On the Commodore 64 the job was simpler because the registers and memory of the VIC and SID chip are all mapped in the main CPU's memory area .

So it's an "Action Replay"... :-)

"The Multiface allows you to POKE INFINITE LIVES listed in this magazine and you'll never loose." So she'll always be tight no matter how many times I POKE her every time I reincarnate? Sign me up, guv'nah!

The board design didn’t have decoupling capacitors. That’s kind of a big no no, especially on a reengineered design. However is not all doom and gloom, one can just tack the capacitors to the underside of the board