Drumulator and Efinix FPGA.

A month after my last publication on the subject, a little progress...

And yes, I spent a lot of time on the EMU1 motherboard which, if it still doesn't work, gave me a lot of its secrets which will hopefully allow me to make it work again!

I am therefore resuming the implementation of the Drumulator in an FPGA. This time I test the small simulation board of the machine control panel.

In fact, I have a few issues that I didn't expect with this FPGA. Certainly, its cost is affordable compared to other offers on the market. But I discovered a pretty significant limitation of the implementation of these Efinix FPGAs.

In principle, it is of course possible to do the same thing as any other FPGA with the Efinix Trion range, except that...

It's not that simple. The internal resources are not as flexible as what you can find on other components, which means you have to rethink your way of doing things somewhat..

Basically, asynchronism is not the strong point of these circuits. Well, you will tell me that when we do FPGA, it is not to do asynchronous. Yes... or no. Actually it depends...

Well with the Trion range, the question does not arise : it's 'nyet, tovarishch' !

Once it is well integrated, you just have to review the design. And to validate my 'new' approach, I simply coded a basic Z80 system, accompanied by a very small program allowing me to test the display of the front panel of the Drumulator :

Which allows me to validate not only my way of doing things synchronously now, but also the functioning of the display system.

I can now get back to studying the CTC equipping the Drumulator and conductor of the entire machine.

The next goal is to obtain the same display directly from the Drumulator environment, that is to say with not only the CTC programmed in VHDL, but also the entire generation and reading of the interrupt vector, as well as than his acquittal. I admit that this whole vectorized IRQ system of the Z80 is still a 'happy mess' ;-)

I have (unfortunately) been working again for a few months in national education. Which leaves me less time to do electronics. I still hope to be able to make significant progress on the subject in the coming weeks...