From the beginning, I hated the midi hardware infrastructure

 Couldn't it be that simple?

It's high time to get started, don't you think?

8 ports MIDI to CV/Gate converter.

And now, the resumption of an old project for which I had not achieved the expected result.

I appreciate simple but effective designs. In this little game, however, I sometimes get fooled by choosing a component that meets the criteria of simplicity and functionality but which may present one or more small drawbacks that I think I can overcome with software.

Most of the time, this is the case. Sometimes, well, it fails miserably. In addition to wasting my time programming, sometimes I even have to abandon the concept altogether! This is the case for my previous version of this type of project.

All is never lost, you learn from your mistakes. And then we return to the subject, this time being careful not to fall into the traps typical of this kind of project. That's what I did here.

The image shown below is the second iteration of the basic concept. The previous prototype just served to validate my new concept.

This new study of a MIDI CV/Gate converter is more complicated than the previous version. There are more components. However, it's mostly 8 times the same type of CV and Gate outputs, with just the control processor. So, it's not very complicated actually.

However, I still improved the basic concept by allowing CV output of three types:
-5V ~ +5V; 0 ~ 5V; 0 ~ 10V.
Likewise, Gates outputs can be positive or negative.

I also added two potentiometers and two additional switches which will allow me to configure the device at a minimum. 

In fact, it's not a bad improvement. While I'm at it, I'm also switching from an ARM processor from STmicro to a RISC-V processor. I got used to these new processors pretty quickly. I have mastered them well and find them very practical to use.

The prototype was more condensed. This was not a good idea in my opinion because it did not allow practical handling of the device. The final version will therefore be larger

All that remains is to have the printed circuit manufactured and to test this new version.

A TMS1122 Timer clone in a box.

The glorious era of the 80s

This venerable clock was programmable and allowed, thanks to 20 program steps, to control four outputs with an accuracy of one minute, over a week : gorgeous!

Personally, I have always appreciated the way this type of equipment works. An interface with buttons and a simple and clear display. A few minutes to understand how it works and voila!

So I recreated this type of clock but added some features including being able to program the start or stop of an output to the nearest second. This was woefully lacking on the original device.

Delay or advance can also be easily adjusted, which was not the case with the original machine. Here, there is no specialized circuit for time management. As originally, it is the processor that counts in real time. On the other hand, the precision is not based on the electrical main network pulsation but on the triggering of processor interrupts. As it is not clocked by a quartz, it is therefore relatively sensitive to temperature. In this way, the operation is identical to that of the TMS1122.

Some images of my new version of 'TMS 1122' :

The 16650 type accumulator allows operation with the display for approximately three days. Which is more than enough to compensate for possible power cuts. This time can be extended by putting the clock in 'ext' mode where less information is displayed, which increases the life of the accumulator.

CONCLUSION:

I must admit that the way the TMS1122 works was not at all easy to emulate. What was undoubtedly very 'easy' to achieve in assembler, is less simple in structured language like the 'C' used here. The functioning of the TMS1122 was certainly dictated by the obligation to work in assembler, with limited resources. Emulating the apparent simplicity of how the interface works was no small feat, far from it!

Offering a professional finish and easy to install product, is not easy either. But it's done. As presented, this programmable clock can be installed in a box and correctly manage its four outputs.

I plan to extend the capabilities of this timer in later versions which will improve the features already present and which will possibly offer others.

Stay tuned...