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.

Kitchenaid coffee grinder repair : thank you China

Unusual article on my blog, it's true, but as I enjoy troubleshooting well-built devices that seem to be repairable, I'm sharing it here.

In fact, because the media space on the subject of sustainable development is inversely proportional to the possibilities of real reparations. The main objective being display rather than reality, particularly in France which excels in the art of lying! So, a kind of denunciation here...

I have had this excellent coffee grinder for more than ten years:

Over the past few days, a pungent-smelling puff of smoke has escaped from the engine compartment.

Dismantling the device is very easy. I removed the electric motor and could see that the smell was indeed coming from this motor. I checked the 'coals' to see if they were not worn. They were, but there was enough left to keep the engine running smoothly.

I therefore concluded that there must be a problem with the winding. I have not tried to start this engine again. When it has smoked, it is better to replace it, it is much less risky.

Here is the motor :

Nothing special, it is a motor that operates under 230V DC. I thought it was not going to be very difficult to find its new equivalent. In fact, I was wrong. It was not easy to find a new model!

KitchenAid's after-sales service for Europe is located in Belgium. So I called this service, and on the phone, I had a lady who told me that the coffee grinder model was so old, that she couldn't find the motor reference.

The only thing she could do was give me the phone number of a French after-sales service company affiliated with KitchenAid.

I suspected that she was getting rid of the problem with diplomacy. I still called this company, which was of course, unable to help me.

Important information. I have concluded from calling this service company that if your KitcheAid appliance is not under warranty, the effort to find a repair solution will be non-existent.

So: the repairability of KitcheAid devices is only guaranteed for a period of two years! After this time, if the part is no longer in stock, it's dead! This is absolutely unacceptable. A period of ten years should be possible, given the quality of construction of this type of device. Mine must be approaching fifteen years, I understand, but still: two years!!!

So what to do? Thanks China!

It is not easy at all to find this type of engine reference. In fact, I ended up finding a site that presented an engine whose images corresponded exactly to the one I had to replace. Needless to say that I greatly prefer to rely on real references, but impossible on this engine. So I had to rely on the images shown and ordered the motor while mentally preparing myself for this not being the right reference.

But hey, the price of the engine plus shipping was €39.2: not very risky.

And this morning, a very good surprise was in my mailbox :

On the left, the old engine, on the right, the new one.

From this point, I removed the drive gear from the old motor, as well as the power connector, which I placed on the new motor :

Once that was done, all that was left to do was reassemble the coffee grinder with the new motor, which is very easy to do:

If I count the time it took me to disassemble and reassemble the device, it must have taken me about an hour and a half. I took my time cleaning the entire grinder when reassembling. If I had to invoice my time, it would have cost around €30 or €60 (€30*2) if it had been done by a company. By adding the €30 of the engine, it would have normally cost me less than €100. 

The company would obviously have charged the repair as close as possible to €200. Which, for a person who knows nothing about it, is profitable compared to the €300 that this new machine costs today. (knowing that in any case, even this type of grinder in new condition is no longer repairable since the engine is no longer available in the field of standard maintenance, but that, nobody knows...).

Conclusion: the repair cost me less than €40, which represents less than 7.5% of the price of a new machine. It's a very good deal. It didn't take me long for the repair. However, in the future, I will avoid buying this type of brand which makes a good product but unfortunately at the operating cost which is potentially far too risky.

About China: obviously, my approach is not at all in line with the objective of finance, namely to produce at the lowest possible price and impose the highest possible selling price while requiring replacement as often as possible. Yet this is the image that the standard citizen has of China. Personally, I don't have this image. For me, it is a country that can also produce very good products, I use GoWin FPGAs for example, and which also has such a huge stock of parts that it is often possible to find parts there spares unavailable in the West. 

China has become an important country on the international scene. This displeases in the United States, but hey, it's the game! China is a bit too much of a dictatorship, but hey (again), are western countries really democracies? Hum... I have some doubts here...

Minimalist computing, PLC with an STM32.

Finding a PLC that is relatively simple to use and above all, affordable and also easily expandable is not that easy.

You can use hardware based on Arduino, which costs about a third of what a standard industrial type PLC costs, or use an industrial PLC. The prices range according to the solutions adopted from €300 to €1,200 in Europe, at the end of 2022.

More troublesome, programming software is more or less proprietary and more or less flexible. An Arduino solution will always be more flexible than an OEM solution because you can access CPU resources. What industrial solutions prohibit. but Controllino type boxes are not easy to obtain, especially where I live. It is therefore difficult to offer a finished product in this format.

In fact, and this is my case, if I want to develop specific solutions, neither of the two previously mentioned worlds, Arduino or Industrial, allow me to shape a finished product. I am forced to be dependent on higher layers. From an economic point of view, these upper layers capture most of the added value by producing the least effort because none of these upper layers is in contact with the ground.

To be able to offer specific solutions and at the same time capture the maximum revenue, there are not many solutions. You have to master everything, the hardware, the software and the knowledge that will allow you to do something different but relatively profitable.

Let's go back to the late 80s. PLC standards were not yet established as they are today. So there was some design freedom. Most of the small companies then worked on the VME bus. The advantage was that it was enough to make a printed circuit board and a small front panel to be able to offer a processor or input/output card adapted to the customer's needs.

In fact my basic training allowed me at the time to build complete systems with 68000 processors, based on OS9. It was working very well.

Since that time, generalist manufacturers have increasingly 'closed' hardware and software, so that any personal development is made impossible. Of course, even with proprietary solutions, everything is still possible, but at what cost and with what constraints!

So I decided to create a small processor board olmost VME standard. The bus connector is not VME standard, it is useless. Why? Because an STM32 type processor has absolutely all the internal resources necessary for the development of a PLC. It is just necessary to establish high-speed serial communication links to create a high-performance system at low cost.

Compared to the resources required to create the same type of board based on MC68000, this has absolutely nothing to do in terms of complexity or processing capacity. An STM32 commonly operates at 80MHz, which is 10 times faster than an MC68000@8MHz, especially for PLCs where complex CICS instructions are not used.

So, here is the fruit of my reflections :

This board is only the processor board. It has no inputs/outputs (or almost). It is intended to be supplemented by other cards with various types of interfaces. In the spirit of VME, this allows maximum agility in the configuration of an automatic processing machine.

The result is a very simple design. The software to be used for the development of the application program will be that supplied as standard by STmicro.

In fact, anyone with some knowledge of microcontrollers and C language will be able to program this board. When I have tested it, I will publish the project files thus allowing to start writing code directly.

And in addition, this solution will therefore be open source ;-)

Addicted to GoWin fpga's!

It must be recognized that when one has tasted these GoWin circuits and the simplicity of the development software, it becomes very difficult to resist the urge to use them for a whole host of projects.

I had the opportunity, a few months ago, to replace an Intel FPGA-based module with a GoWin module that I made myself, in a project to rebuild the Micro-Professor MPF-1b:

Multitech - MPF-1 / MPF-1B

The result was that : 

I also use a GoWin FPGA in the final version of my MIDI switch. It works very well.
So why not continue with the recreation of an SP12? In fact at first I wanted to recreate a Drumulator. But given the work done on the subject and the little difference in fact with an SP12, I decided to go with an SP12. 

So I gathered the majority of the digital part as well as the sampling in both directions on a small FPGA-based board. 

It should look like this:

I received the circuit boards a few weeks ago and have just mounted the digital parts:

This time the FPGA system is a bit more complex since the circuit is used with some external memory circuits. In fact, the FPGA does not have enough internal memory to accommodate all of the memory associated with the SP12 processor. No room for sample memory either. Also, some of the memory must be non-volatile and this is not possible with the internal memory of the FPGA.

For the moment, I have not powered this board. I will do that in the next few days.

The next objective will consist in starting the program of an SP12 in this board.
Nice challenge!!!

Korg Kronos main board.

Regarding electronic music devices, I'm more of a 'hold style'. I like beautiful, well-constructed main boards. While consulting on Internet which deal with this subject, I have just discovered that the Kronos range from Korg, works on an Intel motherboard base, and more particularly the D510MO version. 

The first generation of Kronos:

The Intel mother board :

In the idea, why not. The machine works with a customized version of Linux, and some additional boards made by Korg.

But hey, given the price of the machine, we could have expected a professional motherboard, to say the least. But no, this is a low-end motherboard whose long-term reliability is absolutely not the objective.

Personally, I don't really like this way of doing things. We will say that Korg produces good material... but much too expensive for my taste given the way it is developed. You do the same with a low-end PC at 500€, a good sound card and a T1 used for its keyboard and bought for $125 (as me), all for less than $1000!

Note that this probably allows convenient management of the touch panel display. Because for the rest, still very small buttons resembling those of your FM tuner from the 80s, designed to be used 10 times a month like those of the T1. Unacceptable for equipment wanting to be professional!

I may not make friends here, but really, is it serious?!!!

A small audio amplifier based on NE5532.

A small idea, by the way. Why not build a small, compact linear audio amplifier?

In fact, I had the opportunity to test a small amplifier based on an operational amplifier of the TL074 type during the development of the audio part of a Drumulator.

This concept of amplifier exists, obviously. I have only taken examples that can be found on the Internet.

32 circuits equivalent to 64 AOPs are placed in parallel. Push-pull type topology therefore 128 AOPs in service. This should provide enough power for more than adequate rendering. In addition, this circuit does not require any adjustment.

An example of how the circuit can be rendered:

I have some finalizations of track sizes to do and I think I will make this little prototype.

Attempt to clone an SP12 (3)

I just received the SP12 PCB.

Another circuit to build and test. However, this becomes quite difficult due to the lack of components.

Fortunately, I will be able to test the majority of the functions of the board thanks to a few tips. Some of the components will only be available from April or May next year: terrible situation!