J'MSX : for the fun!

The weekend of June 23-24, 2024 took place in Paris, the meeting around the MSX standard:

the opportunity to meet around standard MSX and to compare our achievements with those of others.

I was also able to carry out some tests of my USB cartridge and found that it works well, except on the Panasonic FS-A1. The 48K cartridges seem not to want to launch after loading, although it works very well on my Omega and other machines.

So, I looked a little closer at this FS-A1 and noticed that its bios has some particularities which encourage some owners to replace it with a 'minimal' version. I will investigate this aspect, knowing that the cartridges which did not start on the Panasonic, work without problem on my Omega, without having touched it in the slightest, that is to say with the cartridge loaded with the ROM which did not start on the Panasonic!

Mr. Nishi was present at this MSX day. For those who don't know Mr. Nishi, he is the person who created the MSX standard with Mr Gates, in the early 80s.

No need to make introductions...

Mr. Nishi presented his MSX0 and MSX3 to us. 

So if I understood everything correctly, because I had never managed to understand what was going on since I saw articles on these machines, it would in fact be two machines based on the compiled MSX basic. Obviously these two machines offer an MSX compatible hardware environment, but based on an emulator.

Msx0 would be more specifically dedicated to IOT, while MSX3 would be adapted to computer learning. These two machines are therefore two somewhat dedicated hardware emulators based on a fast processor but I don't know what processor it is.

MSX0

MSX3

Well, until now I hadn't really understood the subject, and I was telling myself somewhere that I didn't really see the point of such a machine. Well now I know that these two machines are of absolutely no interest, sorry Mr. Nishi.

How to say, IOT is... dead! And learn computer science, in France, today, it's python, and that's all. so ok...

Nevertheless, I had the unspeakable honor of posing in the group photo with Mr. Nishi.

For me, the loop is complete. When I discovered microcomputers in the early 80s, people like Gates, Tramiel, Sinclair, Jobs, Woz and the others were simply geniuses and people living in a galaxy other than mine. I was fifteen years old and the future was just beautiful.

Obviously, since then, the reality here, in France, a small country with no future since a long time, my future has been completely different than the one imagined.

Come on, at least I feel like I was a little part of the story...

Those who know me will recognize me ;-)

Thanks to MSX Village for this very nice moment.

MSX show in Paris on June 22 & 23

It's been a few years now that, somewhat by chance, I became interested in the MSX standard that appeared in the early 80s. In fact, 'because' of Sergey Kiselev and the creation of his MSX2 compatible computer, the Omega :

Then, while trying to make this machine work, little by little, I got into its hardware and, through the forums, I met people interested in the same subject.

Since 2021, the year I really started to discover MSX, I have noticed that not only are there reference people on the subject in France, but also that the community is growing, slowly but surely. It's very encouraging.

So much so that this year, the association MO5, an association known in France for its work in conserving computer equipment, is organizing a meeting this year focused on the MSX standard with even the presence of Kazuhiko Nishi.

No, not Billy, the other person ;-)

Here is the information poster:

All information is available here: https://jmsx.mo5.com

EASY USB, a MSX cartridge dream!

Since the beginning of the development of the MSX cartridge, I have integrated the possibility of restarting the MSX computer once the cartridge has been loaded via the USB port.

However, this requires making a small modification inside the computer. Nothing very dangerous since you have to connect a link coming from the cartridge to the RESET system of the computer. I personally installed a banana plug on the case of my MSX OMEGA into which I plug the reset signal coming from the cartridge.

However, not all MSX machine owners feel comfortable making this modification. The question that was then asked to me was whether it was possible to make an electrical outlet controlled directly by the cartridge. Yes of course.

To maximize safety of use, however, there was no question of directly connecting the cartridge to a switching system. I opted for a radio link with the use of small, low-cost modules, specially designed for this type of application.

Obviously, this requires manufacturing a small autonomous electronic system. So here is this system:

Quite simply!

I didn't make the 3D print of the little transformer that I ended up finding. 

But it gives an idea of what the final circuit will look like. A transformer transforms the mains current into 6Vac, rectified then filtered and regulated to 5V for the RF module and the two relay control transistors. Two transistor protection diodes are also installed.

Note that I inserted two relays for the two sector conductors. In this way, when the socket is placed in OFF, we will be sure that the devices connected to this socket will be completely removed from the electrical network.

Ultimate MSX cartridge modification

I made two final changes to the design of this cartridge. 

First modification.

The first concerns the interfacing circuits with the MSX bus : Aoineko, the developer of the MSXgl graphics library who also tests the cartridge, reported to me problems with random startup of his computer. After studying his problem and especially after looking at the datasheet of his Panasonic FS-A computer, I realized that the power supply of this machine was 'unconventional' to say the least. This results in potential ground problems :

I guess you 'see' what I mean. The wire that serves as a ground reference is one of the two wires of an AC power supply! Hmm, I don't like that at all. 

With this type of design, the ground is always noisy for anyone who wants to connect to this type of device by taking the electrical reference of this ground. 

I therefore powered the cartridge interface circuits no longer directly with +3.3V via the cartridge's internal regulator, but directly via +5V from the MSX computer. No no, the problem was not a bad adaptation of the signal thresholds. TTL circuits work very well with commands not in +5V but in +3.3V. The HIGH level must be at least 2V, which is the case. On the other hand, it is true that this leaves a noise margin of 'only' 1.3V in the case of supplying the interface circuits with 3.3V, and given the design of the Panasonic FS-A1 power supply, I tell myself that that's a bit fair. 

Very good, but then I just postponed the problem elsewhere? It's true. But the interface circuits used, even if they can be powered by 5V, still accept signals coming from circuits powered by 3.3V. The minimum voltage for a high signal is 1.7V on these circuits. I therefore gain 300mV of noise margin. I hope this will be enough.

I still purchased a USB bus isolator in case my modification does not work on the Panasonic FS-A1. This will at least validate my 'theory'.

Second modification.

This time, it is the automatic RESET system of the MSX computer. I implemented directly on the cartridge, a system which allows the computer to be placed in RESET mode for the duration of the cartridge loading. In doing so, and once the cartridge has been loaded correctly, the MSX computer wakes up and boots directly from the cartridge : great!

The small 'problem' of this solution is that it is necessary to intervene inside the MSX computer to locate the reset system, in order to connect the RESET 'wire' coming from the cartridge. 

This is a very simple operation to carry out for those who know how to do it, but this is not the case for everyone. The solution then consists of finding a way to turn off the power to the MSX computer and then turn it back on once the cartridge has been loaded. Without using any wired connection because it is too dangerous. So I opted for a wireless solution.

I bought some small 433MHZ modules:

These models are simple enough to use and small enough to be integrated without major modification on my cartridge.

And there you have it... The first tests were functional. I was able to easily turn on and off a small LED connected to a receiver module placed a few meters away.

The receiver module:

To finalize the subject, all I have to do is develop the receiving system. It will simply appear in the form of a remote controllable mains socket. However, I use universal AC outlets so it can be used just about anywhere :

This circuit is simple and easy to assemble. I also think I will use it not only for the type of application targeted here, but more simply as a remote-controlled socket. You can easily find small remote control 'keys' on the Internet that will work very well with this HF receiver.

Warning :

The HF systems and the design of the cartridge have not been the subject of any certification request. However, the transmission power in games is so low that this does not pose a problem. However, not to be used in a sensitive environment such as healthcare centers....

A new era...

Zilog, after having been bought several times, and now owned by Little Fuse, has just announced the end of production of Z80 microprocessors.

The Z80 was introduced in 1976. I remember that year well. I was 10 and it was the summer of the great drought in France. I discovered this processor a few years later, in 1982, when the ZX81 was available in classrooms. It was, and I only realized this a few decades later, too late for me, but this is another story

The Z80 is the circuit that shaped my entire way of thinking about computing. Even today, and even if I work with much more modern and faster circuits, it is my reference circuit. The very example of a computer resource accessible to all, democratic, lending itself to all eccentricities. Unlike the so-called IT of the following decades, which standardized the way of thinking, killed a certain vision of society, destroyed lives by its contribution to the creation of mass unemployment, and finally today, destroyer of human thought.

Reason for which I returned a little over two years ago to machines from the 80s, in this case the MSX standard.

The first MSX computer, th ML-8000 from Mitsubishi

Question: does this announcement of the end of availability of the Z80 signal the end of this craze for the MSX system?

No, obviously. And why? Well quite simply because there are implementations that are either more modern, like the eZ80, still at Zilog, or different, notably within FPGA. I myself had the opportunity to experiment with the implementation of Z80 within FPGA GoWin, during the recreation of the Micro Professor 1 computer. And it works very well.

SO? Well what I 'reproach' to the world of retro-computing is that it is too attached to the 'purism' of retro-computing. Obviously, this attitude can be greatly understood and justified. But, in my eyes, this 'prevents' any attempt to modernize the concept. It is also partly thanks to this that contemporary IT was able to be built, by the obsoletion of the existing, justifying this only by the financial aspect, and not by the real needs on the one hand, and on the other hand, the collaborative aspect of IT rather than the 'large replacement' aspect of a large part of the workers, thereby breaking the Fordian 'tacit contract'.

Today, there are many possibilities to improve the MSX concept, because it is an open system. So, the announced end of an era can, and will I am sure, allow the arrival of a new approach to retro-computing, which will certainly be 'neo-computing'. 

In any case, like the unexpected loss of the feeding bottle to the new born, thus forcing him to move on to childhood, the 'loss' of the Z80, will, I hope, encourage 'retro-computing' to move, therefore, to 'neo computing'.

 

 

A MSX flash cartridge downloadable from USB.

 

We have to be honest, developing quality equipment is not easy. Downloading a cartridge directly via the USB port from your PC to the MSX computer without any manipulation to do is a good idea.

But we must recognize that it is not done like that! I had to overcome hardware problems, software problems, implementation and component supply problems, etc. etc. 

Fortunately, most difficulties come from not having in-depth knowledge of the issues encountered. This is the study side of 'study and development'. We're getting there but it takes time.

So, after a certain number of prototypes, more and more functional, I am now arriving at the 'final touches'.

What is it about? In fact, with the idea of ​​making the loading and restarting process of the MSX computer automatic, just after copying/pasting a ROM file, you have to... restart the computer.

In 'real' life, a computer requires a power off/on sequence to restart on a new cartridge. This is not very practical. So I had the idea of ​​equipping my cartridge with a RESET signal output for the MSX computer.

Subsequently, it did not pose a problem for me to locate the right place on the OMEGA board to force the reset of the MSX computer.

But... that's not the case for everyone. And truth be told, I don't know many people who want to open up their MSX computer to solder somewhere a 'wire' from the outside.

In fact, you have to 'simulate' the action of the ON/OFF button on the computer. Again, there is no question of 'fiddling' with the computer switch. A relatively simple solution therefore consists of making a remote controllable electrical outlet. Obviously, there can be no question of connecting the MSX cartridge to an electrical outlet in any way.

A possible and elegant solution to this problem is to use an HF link. There is no question here of using a complicated or expensive module but rather a basic 'thing' capable of just remote control something.

After some research, I came across these modules:

I ran some link tests. It works really well. So, and as the emission module is very small, I decided to integrate it into my cartridge. In the end it gives this:

All I have to do now is have a few copies of this new version of the cartridge made. Of course, you will also have to make the 'famous' electrical outlet. I have some ideas for making such a socket 'easily' and very simple to operate, while still being safe to use.

Well, I have the impression of building a castle, but, even if it sometimes happens to have difficulty moving forward in the face of difficulties, it is clear that the subject is progressing and that it works better and better, which provides some satisfaction! 

Commander X16, MSX, 8-bit Microcomputers

Since I am of a 'certain' age, I can say that for me, computing stopped somewhere between the end of the 80s and the beginning of the 90s. And yet, I worked in the 'either-called' IT field for almost 40 years. I stuck with boring IT all these years :-(

I obviously started with 8 bits, unfortunately I entered 'professional' mode at the time when 16 bits (Atari, Amiga) were starting to emerge. I found these machines fantastic compared to the IBM 'dung' and other compatible machines of the time.

I must say that for me, the computer cannot be seen as an object of mass manipulation as is the case today, but as an object allowing the expression of a certain art, and must therefore be to this service, and not the other way around.

OK, this being written...

I've long thought that 16-bit recreations would eventually create an alternative market. Actually no. A few FPGA creations from Atari STs or Amigas and then, nothing very concrete.

On the importance of community! A few years ago, I became interested in the MSX standard. Because it was the only architecture resembling a sort of 'standard', used in the world and open enough to allow a single person to create thanks to and with this type of machine. 

So I made a copy of Sergey Kiselev's MSX Omega computer. And, one thing led to another, I found myself creating material around this machine.

I also watched with great interest the videos of The 8-Bit Guy aka David Murray and his concept of a dream computer.

Wikipedia

After several years of questions, controversies and prototypes, an electronic board is finally available. At the time of these lines, this is the second version :

So I received a small package containing an order placed at the end of last year.

The content contains the bare minimum:

I must admit that I did not expect to order a PS2 keyboard and mouse more than 30 years later!

As for the motherboard, I must say that it is absolutely professional quality. I remember the first PC and PC-XT motherboard. This has nothing to do with. And I love the three ISA type connectors allowing the construction of various expansion boards.

In my opinion, this is what is missing from the MSX standard. But that can change ;-)

The Commander X16 is a machine in the spirit of the Commodore 64/128 based on 6502. The MSX is based on Z80. I think I'm going to stop at these two machines, it already represents a lot of work developing on these two platforms!

There is also the AgonLight machine, but I must say that it interests me less. It doesn't really have any means of extension. I find it too closed, but that's my personal opinion. If a new version is developed with what I consider to be the bare minimum, I might be interested in it.

In this post, I have only touched on the subject. These three machines involve the efforts of many people. I thank them here for their inspiring 'work'.

A flash cartridge downloadable from USB, a few days later.

As I indicated in my previous post, I had almost reached the end of creating my USB downloadable cartridge, but unfortunately, the USB protocol generates periodic activity on the USB bus, which is disrupts operation of my cartridge. This involves unplugging the USB cable once the download is complete. This was not the objective that I had set for myself, namely to leave the cartridge connected to the PC while being used in an MSX computer.

So I had to find a solution. In fact it is very simple, use two processors on the card. The first manages USB communication, the second manages loading the cartridge and providing data to the MSX bus.

Yes, two processors. As the entire software aspect is already developed, all I will have to do is manage the communication between these two processors to finalize the project. As in any case the cost of the additional processor is comparable to that of a DIP FLASH, this solution is not that 'absurd'.

And the result of my thoughts is this:

I must say that the result is quite clean. I still have to check the placement of the notches because on the previous version, I realized that the insertion into the case was slightly forcing.

Ah yes, I also added the possibility of choosing the slot in which this cartridge should operate. Like this, the 'concept' is complete.

A flash cartridge downloadable from USB.

Everyone knows the cartridge system of microcomputers from the 80s. The MSX, a machine from that era, is no exception to the rule.

When you don't know anything about this type of machine, and when you finally get one, the first thing that comes to your mind is to see how it works. And so to do this, insert a cartridge, if possible of games, obviously!

This is when the problems start. How to do today when MSX has been commercially dead for more than 30 years. How to find such cartridges. It is of course possible to find them on the second-hand market. But buying 10 cartridges to test 10 games, well, that's not really viable.

The idea came very quickly to see if it was not possible to have a cartridge that could be refilled on demand, by SD card or USB device.

The Carnivore 2 cartridge, which also offers extras, uses a FLASH card to operate. You have to be able to find a compatible flash card, which is not always easy. I was never able to use the one I bought. The FPGA was poorly soldered and the cartridge quickly became unstable.

Straight into the trash :-(

There is the MegaFlashROM_SCC+_SD. It's the only one I managed to use. But to use it, there is a whole procedure to follow which is boring. And if you don't do this every day, you will have to find the documentation each time to successfully re-initialize the cartridge and copy your new game into it. The least we can say is that this solution is not practical at all. In addition, you have to use utilities that are provided in the cartridge while understanding what you are doing. And when you don't know anything about MSX, it's not engaging!

There is also the solution using a USB device like a key. For this, the rookie-drive-nx cartridge seems ideal. But also, after reading the documentation, I have never been able to get a USB device to be accepted by this cartridge: frustrating.

There is also the SD 512 but given the price of my three previous purchases, I decided I was going to discontinue the charges. So I haven't tested it.

Because, in fact, my goal was to test as easily as possible an MSX board that I had just built, Sergey Kiselev's OMEGA computer.

I had been dying to get my Omega board working for a while now. Because I don't want to spend more on a specific keyboard, I took the time to develop a USB keyboard converter to the OMEGA computer. 

I have also made the result of my work freely available on Github at this address: https://github.com/sillycony/USB-keyboard-to-OMEGA-converter.

So... I was looking for a solution to make this machine execute something in a simple way. This is how the idea of ​​creating a cartridge that can be downloaded via USB came to me.

I don't know if this is the easiest solution at the moment because I'm in the design phase and it's not yet finished despite several previous prototypes.

But I know that once finished, the cartridge will be very easy to use. Simply insert it into the cartridge port of the MSX machine while also connecting it to the USB port of your PC. Dragging and dropping your binary file onto the cartridge, which will be seen as a USB key, will be enough to make the ROM for the MSX available in a few seconds.

If the final solution for my cartridge is not ready yet, I am posting about it now because I have almost achieved what I wanted.

But why is the current beta version not satisfactory?

Well it's very simple: because the USB protocol imposes regular requests from the host to the device to check its proper functioning. And it happens every few seconds.

And? Well, the response process requires the processor on the cartridge to respond ;-). And that takes time. Even if the processor used is fast, while it responds to the USB request, it cannot respond to computer access via the cartridge bus. Result: the MSX computer crashes! But, when the USB cable is unplugged, everything works as expected, as shown in the picture above.

I even planned the automatic RESET of the MSX computer while loading a new binary, so that it then restarts on its own on the new game, or new application. It works very well.

I therefore need to dissociate the USB bus management function from that of the MSX bus management. Because I don't use a FLASH strictly speaking, but the flash contained inside the processor. 'Small capacity' flashes in DIP housing and parallel addressing are becoming more and more difficult to find and more and more expensive. 

So I don't have this problem with a processor equipped with the desired amount of Flash. In addition, it makes routing the printed circuit easier.

The final cartridge diagram looks like this:

I know, it's difficult to read. It's just a screenshot. But we can notice two big circuits there. These are the two processors used. The one on the right is in charge of the USB port, the one on the left is in charge of storing the binary of the cartridge and presenting it to the MSX bus. 

This will cost a little more to produce than expected, but as the two processors are the same models, I will be able to take advantage of the quantity order to reduce the final price.

The software is ready and validated. All I have to do is implement each processor with its part and add a small communication protocol between them. The most 'tricky' part consists of creating a new printed circuit board with more components. But I think I can use the design of the current cartridge to facilitate this new implementation.

I must say that this is now the second project that I have carried out with a professional type process with all that this implies of prototyping, extensive testing taking into consideration a whole bunch of parameters including price, ease of realization, reliability etc etc...

I must say that it is a very enriching experience... When I think of what the type of job I had at the French university was, just a few months ago... What mediocrity!

MSX Omega board : first game!

Difficult start to the year. I haven't published much in 2023. But here's a little new that delights me: I was finally able to launch and play a game with my Omega board.

The Omega board :

I didn't have a keyboard at the time, and given the cost of building this board, I decided to use a standard USB keyboard. So I made an adapter to connect a cheap commercial keyboard to the Omega:

The results of using this adapter were satisfying, but I didn't know why I couldn't use the Omega board correctly. And then someone gave me a new BIOS that was visibly better suited. From that moment, I was able to use the MEGAFLASHROM SCC+ SD cartridge to install the Galaga game on it.

Why Galaga? because a user of my USB keyboard adapter project (https://github.com/sillycony/USB-keyboard-to-OMEGA-converter) told me some problems with Galaga. So I solved these problems and tried this game with my corrections.

The system being fixed and tested for 'small' USB converter bugs:

There you go, the game works perfectly. Maybe I'll make a little video, but before that, I'd have to improve at this game where I'm particularly bad!

Champagne: first time I run a 'real' game on my 'own' computer!
Little video of the game. It's obvious, I'm not an inter galactic champion ;-)

Small note anyway. You have to know a lot of little things to successfully operate such a system. Nothing complicated but the documentation is fragmented. You often have to try to put the pieces together to understand how it all works. This is what I 'reproach' the most to this type of system. Too bad, because it's really fun to work with.

UPDATE 03-07-2023

As I have to perform various tests on several games in order to fine-tune the operation of the USB keyboard converter, I realized that this requires somewhat tedious cartridge loading manipulations. I am therefore in the process of preparing a somewhat particular type of cartridge which will be very easy and quick to use. I say no more for the moment. If you are interested in a simple and easily reloadable cartridge, let me know in the comments, indicating a price that seems 'reasonable' to you.