msi Posted December 13, 2012 Report Share Posted December 13, 2012 A while ago I posted some inquires into making an analog synth along the lines of a Juno 106. I hit a barrier when the design started getting more complicated and required more parts than I was willing to utilize. I set it on the back burner to think on other ways to achieve my goals. I've started contemplating using a pic as a standalone DCO. The limitations I can predict are the output would only be a square wave and possibly problems depending on the speed of the pic. The pic would run completely independent. Once power is applied the pic would enter a program loop and start scanning the CV input for voltage. The only requirement is a voltage present at the CV input. I've come up with a preliminary hardware plan. The pic would be a 16F1825. RC3 is the AIN for the CV voltage. This is connected to a CD4051 which is reading the voltage at the pins of it's input. It is being controlled by the pic via RA3, RC4, and RC5. Additionally two inputs for pulse wave modulation are included. RA0, RA1, RA2, RC0, RC1 and RC2 are then available for six square wave DCO's. The program code as far as I can tell once the main loop is entered would be, - Entry point - Set CD4051 to first input - Read CV at RC3 - Adjust frequency of DCO1 at RA0 to match - Repeat for DCO2 through 6 - Read PWM from CD4051 - Return to first step Concerns I have due to my inexperience with micro-controllers is just how much overhead will the pic need to achieve this. I know a single DCO is possible as it was done as shown here, PicSynth Homepage. I am unsure if more than a single DCO is possible. Does anyone have any suggestions or advice? Quote Link to comment Share on other sites More sharing options...
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