dsPIC Audio DAC board

PCB Plot

Assembled board

Hardware

• Microchip dsPIC33FJ64GP802 Microcontroller with 64kB Flash, 16kB SRAM, ADC, Stereo DACs, I2C, SPI, etc.
• Microchip 24aa256 I2C 32kB EEPROM.
• Off board stereo audio outputs (+/-5Vpp, DC-coupled)
• Off board analog CV / Pot port with 4 x 10V CV + offset pot.
• Off board analog/digital expansion port with 7 MCU I/O.
  • Up to 2x 12-bit ADC inputs.
  • Up to 7x GPIO with pulldowns for switches / encoders
• Optional crystal clock source for improved frequency stability
• MIDI Input port
• ISP port for MCU development and debugging

The principle reason for this board is development and deployment of simple digital synthesis systems. I've already breadboarded most of this circuitry for other projects and wanted something compact and inexpensive that could be used to encapsulate their functions for permanent installations, as well as to serve as a prototyping platoform for future development.

Potential applications include:

• Voltage-controlled digital oscillators
• LFOs
• Envelope / Transient generators
• MIDI-controlled digital synthesis
• etc

Here's the schematic.

(More to come as developement continues>

Firmware

dsPIC code for this will be developed using the freely available Microchip MPLAB IDE, including an assembler and GCC-based C compiler. Once the basic hardware is checked out I'll post skeleton assembler and C projects that can be used for individual development.

Status

06-15-09 - Start schematics.

06-21-09 - Submit rev 1.0 board layout to fab.

07-13-09 - Received PCB from fab. Assembled board and tested some functions.

Return to Synth page.

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