|Name:||dsPIC33 Sampler Board|
|Status rev1:||Completed. Interrupt driven ADC. 115.2k baud serial. Data collected into a 512x4 buffer. System runs at 237kHz sampling four channels simultaneously. Too much system noise. Four octave DDS audio synthesis added.|
|Status rev3:||In Work. Improved power and ground isolation to reduces system noise. USB interface integrated and provided system power except for audio output amp. Removed I2C and audio preamp. Data collected into a 512x4 buffer. System runs at 237kHz sampling four channels simultaneously. +9v power only used for audio output amp.|
|Summary:||The dsPIC33 Sampler board is used to evaluate the 1MHz+ ADC and 70 MHz DSP processing power of this device. Quad channel inputs, a mic + mic-preamp, a 2Mb serial flash chip, and other peripherals are added for flexibility.|
|Specifications||70 MHz DSP, 1MHz+ or 250kHz four channel ADC, 2Mb storage, audio preamp(rev1), audio out amp, 5v and 3.3v I2C(rev1), 3.3v serial FTDI/USB and Bluetooth port(rev1). 5v USB integrated onboard(rev3).|
|Dimensions:||3.8" x 2.5"|
|Power:(rev1)||7 - 12 VDC|
|Power:(rev3)||USB 5v. 7-12 VDC for audio amp only.|
|Schematics||dsPIC33 Sampler schematic pg 1
dsPIC33 Sampler schematic pg 2
dsPIC33 Sampler schematic pg 1 rev3
dsPIC33 Sampler schematic pg 2 rev 3
Rev1: The dsPIC33 Sampler board is designed to provide one channel of 12 bit data
at 1100 kHz or four simultaneous channels of 10 bit data at 250 kHz.
It includes an electret microphone preamp and two opamp buffers. Both provide signals biased at 1.615v for the 0 to 3.3v ADC giving a bipolar +/- 1.615v data product.
A 2Mb 40MHz serial flash is available to store data.
Both a 5v and a 3.3v I2C interface are provided.
A 6 pin serial port configured to support 3.3v FTDI/USB and Bluetooth modules is provided.
The board has a 0.7w @ 8ohm audio driver connected to a high speed PWM port though a 10kHz low pass RC filter and volume control pot.
As with most boards, it also includes a PIC ISP programming header, +5 and +3.3v voltage regulators, and a status LED.
There are various jumper to isolate external voltages from the on-board regulators.
Rev3: Removed the microphone, audio preamp, and I2C interface.
The serial interface was replaced with a USB/FTDI chip to provide power and serial interface.
Separate digital and analog ground planes were used and efforts were made to isolate digital and analog power.