dsPIC Functions

dsPICfun PCB dsPICfun PCB

PCB Plot and Assembled Board


This is a test-bed for using the Microchip dsPIC33FJ128GP708 in control voltage processing applications. It supports four channels of input/output with a +/-5V range, plus four ratiometric pots for real-time control. A 16x2 LCD, encoder and two buttons are used for setup and configuration. Power requirements are +/-15V and +5V. Programming and debug are supported with a 5-pin ISP connector. A 4-pin 3.3V UART connector is provided for access to serial I/O, including MIDI. An 8-pin DCI connector allows future expansion with an off-board audio codec, and an 8-pin AUX connector provides access to GPIO and/or hardware-backed SPI and I2C interfaces.

Here's the schematic (updated 1-17-2009).

Here are the gerbers.

Here's the BOM (updated 1-17-2009).


Preliminary firmware is running on the board and most functions have been verified. As of 1/5/09 I've tested out the dsPIC, the SPI DAC, CV inputs, CV outputs, Pot inputs, LCD, and buttons. The rotary encoder, UART, DCI and aux digital I/O ports remain to be tested.

Here's Rev 0.3.


Csaba Zvekan built one of these and documented his work on his own website.


Several of these boards have been built and there are a few bugs in the layout which have emerged:

Rev 2.1

dsPICfun rev 2.1 PCB

PCB Plot of Rev 2.1

Schematic & layout have been updated to correct the above errata. Also, the spare I2C port on the dsPIC is now connected to an optional 32k x 8 EEPROM.

Here's the new schematic.

Here are the new gerbers.

Here's the new BOM.

Return to Synth page.

Last Updated
Comments to:
Eric Brombaugh

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