This Monday I'll travel to Barcelona. I'll take this oportunity to acquire new components (do you believe it? I have a lot of 32K SRAM, but no 128K ones! ). As I don't know how much time wil pass until I could travel again and acquire more components, I'll try to get enough material to cover as many projects expected to take place during Summer.
So I think it's time to present an idea I've been coving since January, when I (accidentally) found a MC-16 schematics scan. The MC-16 was the first sound card the Apple ][ had, and (I may be wrong) it was maybe the first commercial sound card a microcomputer had.
Examining the diagrams I learnt some things. First, that a simple soundcard contains two sections: an analog one containing an operational amplifier, DACs to control the volume of each voice and resistors to mix the different voices; and a logic one which is a programmable signal generator. In the case of the MC the signal generator is a 8253 PIT, which was made as a support chip for the 8085. The original PIT is not made anymore, but the 82c54 is still in production and they are compatible.
About the name of this project:
I decided to name it "Shakuhachi". A shakuhachi is a very simple vertical flute made of bamboo.
Image courtesy of Wikimedia commons.
Just that, a bamboo pole with some holes. And the MC is just a counter with some DACs... Do you see the simile?
This project is sure that won't be finished during Summer (so no false expectations). But the goals are the following:
#1: Clone the design, adapted to use modern-day components
#2: Experiment the following designs:
#3: If (#2) successful, think about integrating as much as possible in a card.
Thank you for your time and my apologies for such ugly and dirty drawings.