dsPIC Signal Processing board

PCB Plot

Assembled board

Hardware

• Microchip dsPIC33FJ32GP302 Microcontroller with 32kB Flash, 4kB SRAM, ADC, Codec interface, I2C, SPI, etc.
  • Pin-compatible with other dsPIC parts for expanded Flash, SRAM, peripherals.
• Wolfson WM8731 stereo audio CODEC with up to 96kHz / 24-bit sampling.
• Microchip 23k256 SPI 32kB SRAM.
• Microchip 24aa256 I2C 32kB EEPROM.
• Off board stereo audio I/O (+/-5Vpp, AC-coupled)
• Off board analog CV / Pot port with 4 x 10V CV + offset pot.
• Off board analog/digital expansion port with 8 MCU I/O.
  • Up to 2x 12-bit ADC inputs.
  • Up to 8x GPIO with pulldowns for switches / encoders
• Codec expansion port with headphone driver output and microphone input
• ISP port for MCU development and debugging

The principle reason for this board is development and deployment of simple audio DSP applications. 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. Thi

Potential applications include:

• Filters
• Distortion/Modulation
• Chorus
• Phase/Flange
• Short Delay (approx 1/3 second of storage at 48kHz)
• Vocoder
• Granular 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 boards from fab.

07-18-09 - Assembled board, codec working.

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