And now :
In fact, telephone numbers in France went to 8 digits on October 25, 1985. The Drumulator was marketed in 1983. The copy I'm troubleshooting therefore went to Music-Lab between 1983 and the end of 1985. Almost 40 years ago...
And now :
In fact, telephone numbers in France went to 8 digits on October 25, 1985. The Drumulator was marketed in 1983. The copy I'm troubleshooting therefore went to Music-Lab between 1983 and the end of 1985. Almost 40 years ago...
Yes, well, at some point of your life, we have to close certain projects that have been in progress for... a very long time, such as having a ZX81 at home.
Given the relatively small size of the circuit, I thought it was going to be complicated to route all the tracks. Ultimately that was not the case.
Everything is not routed according to the rules of the art. That's not bad, it will allow me to put my finger on the potential problems more easily.
We just have to wait for the receipt of the printed circuit...
Now that I know how to manage the samples using the micro-sequencer I created in VHDL, I have to study the analog part using a converter other than the original one.
The AM6072 circuit is obviously no longer available. It is therefore necessary to use a standard DAC instead of the original companding DAC. I will use a lookup table in the FPGA to modify the response of the new DAC.
In order not to launch myself right now in the realization of the Drumulator clone, I must test the sound generation of the eight channels using the new DAC. So I started to create a little test circuit board:
Some time ago, I coded the whole processor part of the Drumulator in an FPGA. I still had to code the sound generation sequencer. I thought it was complicated to achieve, given the schematic in the service manual.
The sequencer looks like this:
About a month ago, I talked about the development of a MIDI switch based on an FPGA. This system will include logic elements, as well as a processor to control everything. There are proprietary systems for developing software for embedded processors quite easily. As I decided to use independent solutions, I had to implement mechanisms to allow easy debugging. In particular, I installed an external ROM support on which I can insert a simple EPROM emulator :
January 2022 was a bit special for me. I left my job as a computer scientist in the administrative services of a French university. After 20 years spent with fools, I decided that it was high time to resume the course of a healthy life, at least on the psychological level.
And it doesn't matter if it's me who's crazy!