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! 

MSX Omega computer : USB keyboard interface.

A few weeks ago, I talked about Sergey Kiselev's MSX2 compatible processor board project and the choice I made not to build the keyboard for reasons of overall system cost. 

Not everyone will agree with this choice, but for me, the main thing is to be able to have fun in retro-computing without breaking the bank. In fact, I specially studied an adapter for this MSX board to allow the use of a standard USB keyboard:

As usual, after a few days of waiting, I received the PCB:

This board is not particularly easy to assemble by hand because of the two integrated circuits with very thin and close legs. But with a little patience and skill, here we are. First I powered this adapter and plugged in a USB keyboard. I was able to observe the lighting of the keyboard connection LED as well as its flashing each time a key was pressed on the keyboard. It seems to me to be a very good start since the reaction of the USB control IC corresponds to what is indicated in the datasheet. In principle, all that remains is to program the processor to provide the parallel code expected by the MSX board.

A small additional check was carried out to verify that this adapter board fits correctly on the OMEGA board:

Note that I chose a raised USB connector to allow easy insertion of the keyboard connector. My adapter looks perfect! In fact, I have to quickly program it because without a keyboard it is obviously impossible to use the OMEGA computer.

However, for some time I received a Carnivor cartridge to allow me to copy programs or games to it and finally test the proper functioning of the OMEGA board:

At least I have already been able to test that this cartridge fits correctly into the connectors of the OMEGA:

I may also have to find a joystick for this machine. Otherwise it will be difficult for me to really test the games ...

Omega computer : USB keyboard interface.

A few weeks ago, I talked about Sergey Kiselev's MSX2 compatible processor board project. I have completed the assembly of a copy of this board. I like a lot the style of the result:

Personal picture.

I equipped this board with the system, also MSX compatible, C-BIOS ver 0.29. The whole system works perfectly.

Personal picture

But, for the moment, I do not have a keyboard or cartridge to interact with the machine. Given the cost of building this type of material that uses original components, I decided to test the adaptation of a standard USB type keyboard instead.

I have therefore developed a small circuit which will take place in the keyboard connector of the Omega board and will directly provide an input for a USB keyboard:

Personal picture

The finished prototype should look like this:

Personal picture

I must also plan to use a ROM or FLASH cartridge in order to test some software applications. The MSX environment is increasingly dynamic. New games continue to be produced. 2021 looks promising! 

I have some ideas to try to improve the performance of this type of material ...