The P2 HD Audio Add-on Set is a specialized ADC and DAC combination personally designed by Chip Gracey to extend the high quality audio capabilities of the Propeller 2 Smart Pins into the real world. For over 30 years, Chip has created audio examples with microcontrollers as part of his personal audiophile interests. He chose high-quality components for these boards, which are assembled and tested at Parallax headquarters in Rocklin, California, to support his own projects. This P2 HD Audio Add-on Set will enhance your projects as well.

This hardware demonstrates the Propeller 2’s abilities with a precision DAC/ADC in two code examples. The first example streams audio from the ADC inputs, optionally applies digital effects, and then plays the audio back out through the DAC output at line level or directly to headphones. The second code example shows how to drive the DAC output directly with sound frequencies generated by the Propeller 2. These sound effects could be useful for audio feedback of different states of control and debugging, robotic sensing, public announcement or alerts.

This add-on set is supplied as a kit including both the ADC and DAC boards. High-quality Each board is compatible with any standard single Parallax P2 accessory socket found on most P2 development boards, and are designed to fit side-by-side if installed at a dual port. The connector is a standard 2×6-way 0.1” pitch socket, and the boards could be used with a wide range of microcontrollers that use 3.3 V signal levels.

The ADC has 4 input channels available via two stereo 3.5mm jack sockets, or at two sets of unpopulated 0.1” pitch 3-way header pads. The DAC has 2 output channels available via one stereo 3.5mm jack socket, or unpopulated 0.1” pitch 3-way header pads. The jack sockets can be used in mono or stereo modes, to allow the left and right channels to carry independent signals, or to be part of a stereo pair.

The P2 HD Audio Add-on Set extends the high quality audio capabilities of the Parallax P2 multicore microcontroller Smart Pins into the real world, and enables advanced sound capabilities, processing and effects commonly used in robotics, interactive displays, conferencing, stadium, studio and industrial applications.

P2 HD Audio ADC Features:

Based on the AK5704EN 32-bit 4ch ADC with MIC pre-amplifier
High performance analog front-end A / D converter IC ideal for voice recognition, voice control, and conferencing applications
Superior low-noise recording with low power consumption
VAD (voice activity detection) feature further reduces system power consumption
Supports ultrasonic recording
Sampling frequency from 8 k to 192 kHz
MIC input jack configurable for line level input signals, for up to 4 channels of line input
MIC input channels have configurable voltage pull-up for use with analog microphones
2×6 female socket with 0.1” spacing compatible with the standard Parallax P2 Accessory sockets

P2 HD Audio ADC Specifications:

Supply voltage: +3.3 VDC
Control interface: I2C bus (400 kHz)
Max bits: 32 bit
Max fs: 192 kHz (typical 48 kHz)
Max S/N: 105 dB
MIC amplifier gain: +30 dB to 0 dB, 3 dB step
Form factor: dual 2×6-pin female pass-through headers with 0.1″ spacing
Mounting hole: 3.2 mm diameter
Operating temperature: -40 to +185 °F (-40 to +85 °C)
PCB Dimensions: 1.6 x 1 in (40.64 x 25.4 mm)
RoHS CE & UKCA Declarations of Conformity are available under the Downloads tab

P2 HD Audio DAC Features:

Designed to leverage the Parallax P2 multicore microcontroller Smart Pin DAC modes
Configurable with a range of drive strengths, from 18 to 990 ohms
High performance output ideal for announcements, music and general sound monitoring and reproduction
Superior low-noise output with low power consumption
2×6 female socket with 0.1” spacing compatible with the standard Parallax P2 Accessory sockets

P2 HD Audio DAC Specifications: