OMEGA MSX COMPUTER

With Covid, it's not very easy to move forward with the projects I'm working on right now. For example, I am mounting an MSX type computer board. This is Sergey Kiselev's Omega project available on Github at this address: https://github.com/skiselev/omega. The computer looks like this when mounted:

https://github.com/skiselev/omega

This computer is built from standard 'old' components but still relatively easily available. On the other hand, this implies the use of a multitude of sources of supply because it is totally impossible to find all the components from one supplier. Not that it's complicated, but it really takes a lot of time and organization. We also have to face long delivery times due to the Covid. The assembly of the board is not of great complexity but requires patience and a good practice of the soldering iron. It is definitely not a beginner's job.

My first board is almost finished: 

In fact, I have ordered components for several boards. No need to generate all these global transports for a single copy. I may offer a few mounted boards for sale. I plan to use this first one as a prototype for some future developments, because the MSX standard is still active and dynamic.

The Z80 which equips this type of equipment is definitely an excellent processor for familiarizing yourself with the architecture of computers and their programming. This is obviously a totally different approach to the 'virtual' world that is programming under Windows for example. I think that creating an application for such a machine is much more rewarding than running your first (boring) 'Hello World' application in its 'little window' ;-)

Other projects will soon be completed. I'll post on this blog when it's done ....

PLC PACK for the Colour Maximite 2

After working for a while on the development of the vintage PAL reader for the Color Maximite II micro-computer, I went on to test the PLC type expansion board.

This expansion is equipped with

• - 3 opto-isolated logic inputs.
• - 3 relay outputs
• - 2 analog inputs 10V
• - 1 DS18B20 input
• - 1 TTL serial communication port
• - 1 RS485 serial communication port (optional)

The tests are almost finished :

In this picture, I have connected two control/command screens of different type.

I connected a Nextion screen whose communication takes place by TTL serial link and thanks to a very simple exchange protocol in the form of ASCII frames.

I also connected a second screen which is used in PLC systems and which communicates in Modbus ASCII through an RS485 link. This screen is used to test the control of the outputs of the PLC board.

The program in Basic uses an interrupt to manage the system timer, another interrupt to manage the triggering by the logic inputs of the board and finally a last IRQ for communication with the industrial screen.

Everything works smoothly and very responsively.

I am very impressed by the efficiency of this system, as well as by the basic interpreter which allows to manage without problem all these different interfaces.

The original Colour Maximite 2, an ARM7 based micro-computer :

https://geoffg.net

Soon a more detailed description on https://sillycony.blogspot.com.

Vintage PAL reader.

How to find the equations of old PALs that we find in vintage machines?

With this PAL / GAL reader:

More info here.

A Drumulator in a FPGA?

After getting back to working with FPGAs for a few weeks, I took a first study of the Drumulator processor core to implement it in a Terasic DE2-70 board:

Obviously, shown like this, it is neither very sexy nor impressive. But, thanks to the keyboard with serial link previously made, I was finally able to observe for the first time the operation of the heart of the machine. 

More informations here : https://synthlan.blogspot.com/

uPF--2? In fact, an uPF--1 in FPGA!

The concept of the Z80 development kit based on an FPGA board is validated :

more info here: https://sillycony.blogspot.com/

Reader of Vintage PAL (next)

That's it, the reader of vintage PAL is functional. It can read old 20-pin PALs found in vintage synthesizers or computers. This makes it possible to find the equations of these programmable circuits and thus to program more modern components such as replacement GALs, with a GAL programmer like the MiniPro.

The PAL reader.

The Mini Pro programmer.

More info here: Reader of vintage PAL

The new three output PSU is validated.

VALIDATED! 

More information at : The new three output PSU is validated.