Speaking as someone with a passion for retro systems but no X16 or Agon 2 I feel I don't have a dog in this 'fight' but a good deal of interest. IMO the Agon is all round a 'better' system for it's price, simplicity, performance, and BBC Basic. But I do sincerely bemoan it's lack of a 'proper' expansion bus - GPIO doesn't cut it for what I want to do. But here's the thing... ...from the perspective of an 'outsider' I find the X16 more interesting and from what little I've seen so do other people. Is it more of a 'computer'..? Sadly the (IMO) overcomplicated X16 is too much money for me. If the Agon at the very least had a defined expansion bus, even if it wasn't included on the 'consumer' version I could at least do one myself happy in the knowledge that any cards I designed for it could be used by others. If I come up with my own expansion bus who will use it but me? PS: Frankly the RC2014 scratches my itch for a 'new old' computer - it's retro enough and easy to use, while being endlessly expandible in any direction you care to take it - Probably because it's at heart a backplane design who's base modules get you up and running with a basic CP/M system that you can go nuts with should you wish, but you don't have to.

I like Foenix Retro System Computer.

If anybody wants to hate on another retrocomputer project by a complete amateur, see my PUGPUTER 6309. It's got an HD63C09 at 3.58MHz (same CPU as Double Dragon by TAITO), 1-4 MB of SRAM, a V9958 video chip, and a YMF-262m for OPL3 sound synthesis. It's mostly working now, and it totally sucks.

You could add protection to just about any 8-bit micro back in the day, by using the early 9-bit memory DRAM SILs, and routing the 9th bit to an interrupt pin to raise an interrupt when attempting a read if the 9th bit had been set. And the 64Kx9 SILs meant that *any* memory byte could be protected. I designed a 6809 system that way around 1982.

While I agree that V9938/V9958 are a missed opportunity in what they could have been if their design was cleaner, however they are still my favourite choice when I choose what graphics feature set to use in retro development projects. Look: the X68000 has a really weird square resolution, and besides it has lots of features very hard to master. The HAM mode in the Amiga is a dirty hack that I never enjoy programming for. The NES has a very limited color palette. In the end, the V9938/V9958 offer exactly what I want, and no other chips from the era come close. Even the later V9990 got it wrong by not supporting sprites it bitmap modes (it supports them in pattern modes only). I know the V9938/V9958 have sad limitations, but they are the vintage graphics with the best feature set. No other chips got it better (they were faster, but their features were poorer or even dirtier to program).

The title is just clickbait because there is no secret about z80 discovered here. Neither the already well known and broadly used bank-switching to access more than 64k of memory nor your so called "protected mode" are hidden features of the CPU but features of the surrounding circuit. E.g. the KC85/2-4, Home computers build in former East Germany used the high address bits for a quite nice module concept. Decoding Instructions by external hardware was also already used by support chips like SIO/PIO/CTC. (the RETI instruction had special meaning for those chips)

Can't seem to find "the hate" video referenced here.

Can't listen. The background music is too loud.

I try to cut my V9958 some slack because of it's age... but it is starting to get on my nerves! On my 3.57MHz bus-clock system, I have to insert TWELVE NOPS after each pixel write in GRAPHIC7 or in YJK modes. So drawing a full 256x212xYJK frame takes like 0.5 seconds. I'm starting to consider using a Pi Pico 2 for video in my project.

As a long time fan of the 8 bit guy, with all due respect, *shut up.*

Wow ^_^ That's cool. IM2 still be ok if allowed in certain (protected) page, or maybe even IM0 with specific command feeding to the bus. (Btw, do you consider ez80 as retro? =)

Not really clickbait. Clickbait is a trick to get views for videos that aren't worthy of the views. You tempted us to take a look and you actually delivered a very good video! Sure, not technically honest, but in spirit, this was a very honest video. Clickbaiters are selfish; you shared an obvious labor of love presented carefully and thoughtfully. Thank you!

KZbin automatic subtitles do not like the name of the guy who designed the Z80...

wiat what...

The x16 is what it is, a very nice 8-bit computer. Unfortunately it's not compatible with anything. Personally, I would have liked to see it as a siper C64. As far as the prices are concerned, the final disappointment is quite large. The original target was probably around 200 USD and scaled-down versions that were supposed to cost less than 100 USD. Now the computer costs around 400usd (as a DEV kit). The MisTer, which emulates ( hardware layer ) a number of systems using FPGA, is also in this price range. So is he worth it? Probably not, because it's too special. I either take a Mister, for classic systems, or a Pi with ArcaOS. The only thing I find unfair is that such a shitstorm is sparked by the ARgon side. The computer isn't exactly the cheapest either, around 80usd.

Are u Chud?

How does a 16 year old have a retro attic lol.

I feel like the V9958 is an excellent chip if you understand what it's good at, and what it's not. It clearly needs more cpu grunt to really take advantage of it than a 3.58Mhz Z80 if you're working on a modern project. I've been wanting to use it with a 4-8Mhz 65C02 or 65C816 in a homebrew project, and see what it could do for a few years. I've had various thoughts on to handle things. The nice thing about the 65XX chips is that they have really tight memory access times, so this could help things or hurt things depending on your view. Depending on what you're doing, it can run circles around faster clocked chips of the time at the cost of programming, so you have to treat it like an early version of a RISC chip and be efficient. I was thinking of the possibility of using a single 1K dual port ram in conjunction with standard main ram, or even using some logic to handle ram access. Possibly even have it where the CPU accesses things only on clocks the VDP does not. I do know from reading that the V9958 apparently DOES NOT like the block transfer operation of the 65C816, so a direct access to the ram would be really nice. And talking about weird to program for, the 65C816 will really shake things up here. Throw in a YM2203 and a DAC and it could be an interesting little project. I had thought of potentially using one or two FIFOs in it, and use a clone of the Disney Sound Source for PCM audio. An alternative would be a YM2413 instead, but I was trying to keep some little bit of distance from the MSX. There's quite a few possibilities here, each with their own tradeoffs. I've had time to think about things, so we'll see what happens. Still haven't actually started it yet.

Your take on clickbait is the only one where I will be back for more.

Nice vid. Good to see u at vcfmw

No mention of the Second Reality scene demo port on the X16?? *sadface* Google "second reality x16 youtube"

Idea of protected mode is the fundamental failure of computer technology history. That is an embodiment of mental inability of science representatives. The second fundamental failure is the overhyped 'microservice' software approach. There is a lot of other things that should never happen in it history. It is hard to explain why, but the real key to success is not to follow the hyped concepts

Sigh. I'm bored.

Yall need to check out oasis8 by Timothy Williams. First multi user OS for micros and z80

You could probably emulate it all on a pi pico anyway 😂😂 and it would cost you $25 dollars to build! .

This something like the double CPU hack from these times. CPU1 running the code, CPU2 handling memory exceptions and maybe even I/O.

0:14 Dude where can I find this chart?

Hu is this guy

Has anybody else here financed, designed, built, prototyped, sourced all the parts and released their own hardware to market.. without $2,000,000 worth of someone else's crowd funding?

I think the only missing piece is separate supervisor stack :(

That corruption at the end screams bitmap character ROM issues (to me, at least)-it seems like all of certain characters are being affected. I don't know if you'd get such consistency if it were happening at the CRT controller-cache interface, but my guess would be no.

Not sure which is more impressive; Your research of this old card or the compelling quality of the video. Thank You!

There were multiple builds of MW2 (retail) targeting various processor and accessory configurations (edit:) on store shelves _at the same time_ . Maybe one that used one of the (weird) VR/3D goggles/shutters with "3d" controls shipped with the debug build/features on. (edit2: also, I definitely ran it on a 486/75MHz irrespective of what it said on the box .) The 'original' Mechwarrior, I had a (pirate) copy that did leak information to the Hercules(?) monochrome monitor while I played on the VGA one. Though I don't remember if displaying the packet(s) of information it exchanged between the cRPG and simulator programs/modules was something it did, or I did when I wrote a [wrapper] to hack/mod more mech-variants into the game. (An actually competent modder/cracker) said that the simulator could be hacked to continuously render the command view to a second _colour_ monitor; (but would still pause rendering the cockpit screen while you issued commands). ... I'm trying to think of what dual VGA monitor ISA card would have existed at the time. (scratches head) Maybe he meant CGA and VGA?

If it's made in the UK, then maybe they had a bad exchange rate with the USA. I can't remember if the Hercules card came with a printer port ... ?

Great video. Thank you!

So let's get this straight. Every time you read the keyboard, you trigger a non maskable interrupt? For every pulse you send to a speaker (to generate a tone) an NMI will be generated? So how do you write the NMI handler to detect if it's a genuine hardware I/0 being performed or just a switch to protected mode?

You forgot mention that Z80 uses in house appliances and graphic calculators. It is insane that it is being used everywhere even now.

I think the circuit would be a bit simpler if a D flip-flop was used instead of an R-S flip-flop

To those of you who know what a Z80 is: take your ibuprofen.

Good to see you had a shower and washed your hair this time.

Great work! 👏🏻👏🏻

Click bait is usually meant to attract people and SELL something. I don't see anything for sale here.

Well, I think Zeal8bit computer (based on real Z80 CPU) has done a better work. It is not so expensive, with a active community!

A pi pico USB card is doable. I thinks its more Dave not knowing what is possible.

Why does this video have 3/4 of a million views?

Kam nicht der 6802 mit mehr Megaherz später unkompliziert auf auf den Markt bis 36 Mhz. und viel mehr. Dann war aber der Markt schon hier hin und man sollte auch anderen Kram neu kaufen auf den man keine Ambition mehr hatte. Glaub ich nicht ganz so die einredende Darstellung. Er hatte nur als Z80 einen gering schnelleren mathematischen Co-Prozessorteil der im Überschuß produziert worden war und primitiver war. 10 Jahre bereits vorher auf Lager. Der Z80 war nur leicht hochtaktbar. Ok dann rein mit der Käseflocke. Oder auch nicht. Dadurch liefen mathematische Berechnungen halt minimal schneller. So weit so gut. Er hatte aber viel weniger Befehle und Fähigkeiten als der 6502. Deshalb lief er auf Halbmast mit. Dabei gab es auch Übergabefehler bei von beiden über I/O gleichzeitig angesprochenem Ram. Das wurde durch reduzierte Programmschleifen genial und Softwarevernunft schnell ausgeglichen.Aber kompatibel. Bei einigen Rechnern funktionierten verkürzte for next . Schleifen allerdings vorher besser. Manche Einzeiler - Tricks funktionierten dann nicht 100% wie vorher und man mußte leicht umschreiben in andere Trickzeilen. Für Schüler mit Gehirn noch verkraftbar aber zunehmend ärgerlich. Auch bei pop out, aus For next schleifen ging Programmieren auch vorher einfachst und unkompliziert. Auch hatte der Z80 dafür einige starrsinnige Macken. Der Flip - Flopp hier ist doch hier eher geträumter anderer Käse und eine Werbung für andere ?😃Bei Mikrokontrollern war er auch gut, da er schnell in der mathematischen Codierroutine als Interface ausreichend arbeitete und ein eigenes winziges Ram dort besaß.. Dafür war er ja gedacht. Vieles negative haben wir aber Monopolisten mit fehlinformierender Werbung auch gelegentlich zu verdanken ? Die Menschen rennen aber anderen neueren Werbe - Gängstern , naiv hinterher aber deswegen doch nicht gleich in die offenen Arme ? Man muß bei allem etwas pragmatisch und kalt logisch sein. Handys für par Tools , dann ist aber irgendwo bisweilen individuell Schluß , man will doch bestimmtes eher etwas was gelegentlich nützlich ist ? Es sollte aber auch richtig funktioniern. Ein Handy mit einem 680(0)2 und Frequenzversechzehnfacher und einem schnellen Speicherregister würde bei Käse - Unix Basic vieleicht auch schon auf der Handy - Konsole gut laufen ? Jo schon !😄. Gibt es noch mehr zum Aufschwatzen ? Nur wer will all den teueren Werbemist ? und diese Neanderthalerprogrammsprache UnIx ? Wird diese angebetet ? Alles leider über Compiler nur handhabbar. Wenn die weg sind bleibt eine Rückentwicklungswelt mit Rückschlag 200 Jahre für reine Werbeklamotten zurück ?Ein einziges intelligentes Programm, welches auch geht wofür man es praktisch braucht , ist immer noch besser, als ein Narrenschiff oder eine Ache Noha ! (Lieber doch nicht den Unsinn [Nonsens for Goa] um jeden Preis haben). Am Intelligenten sollte man auch weiterentwickeln ? Eigentlich schon. Und nicht dort sparen also nicht umgekehrt ? Heute kann man sogar jede CPU total simulieren in Echtzeit ! Wie eine reverse Transkriptase draufziehen . Also neu erfunden wurde hier nichts . Nur Schäfchenwolle für ein Schläfchen ? Es ist aber immer die Frage nach dem erreichten und gesetzten Aufgabenziel und nicht nur als Lula zum Einlullen. Nur einmal ein anderer Gedanke : Vieleicht haben wir wirklich 160 x Z 80 Core Rechner, wie ein stark 16 fach verkleinerter Solar - Waver, die in 16 Cores als Bananenbündel zusammengefaßt wurden, um den Konsumenten nicht zu verwirren ? oder zu überfordern ? Etwas alles verkleinern mit gewonnener 4 x facher Taktfrequenz ? dazu = > 2 Ghz, Das passt doch. Und dazu die jeweiligen Benchmarktests ? mit Preisliste ? Nur nicht freigeschaltet bei niederem Preis ? und nur 2, 4, ,8 Cores ? oder nur weggelassener Print - Datenleitung in der jeweiligen Produktionskette ? Der Gedanke kam mir allerdings auch schon. Also rückentwickelte Unix - Wollsau Welt ? Das würde sogar über ein Kompensationsnetzwerk bei 5 Ghz und Miniaturisierung nach außen laufen. Ich denke aber eine Entwicklung bleibt nie 100 Jahre ganz völlig stehen ? Und nicht jeder intelligente Geist muß hier gleich kapitulieren. Was er auch nicht macht. Was, wenn jemand mit der echten 100 Ghz CPU daherkommt ? Mit Datentunnelleitungen aus Tunneldiodenrinnen. Die muß man dann ganz schön drosseln ? So groß wie 1/100 Stecknadelkopf ? Was macht man dann mit den ganzen real fehlenden intelligenteren Köpfen die sie richtig einsetzen ? Die auch noch selbstständig denken und rechnen können. Kleiner böser paranormaler Witz : oder man nimmt einen kleinen genetisch programmierten Insektenkopf ? Als CPU. Wird wohl nicht klappen ? obwohl diese sogar Kupfer und Chrom im Blut haben.(eher in der Leber bei der Cytochromoxidase) War eben hier ein ziemlich blöder Witz. (🕵‍♀Chromiumlebensformen ? mit geistig dissozierten Facettenaugen und Werbe - Tentakeln ? aber noch eigenes entwickeltes Insektengehirn ? mit LEDs geschmückt ).Wer weiß das schon so genau ? 😂😂😂. oh my, little jokes !

That's Genius, restomod on the vintage hardware.

Clickbait. You redirected the NMI. That is not protected mode as a new mode. I used this trick and others for making In Circuit Emulators. Nothing new here. NMI is the highest level of exception.

Sweet.

Thanks for the memories.