03 Dec 2024

uDSP-Card: XCORE.AI Development Board for Portable Applications

This post introduces the uDSP-Card, a compact development board built on the XMOS XCORE.AI platform and tailored for portable and wearable applications. Despite its small footprint, it offers rich I/O and high-performance DSP capabilities at low power, making it ideal for audio, sensing, and real-time embedded tasks.

Note: This article is adapted from sections of my Master’s thesis on “Ultrasonic Hearing for Human Echolocation”.

Overview

The uDSP-Card was originally designed for a battery-powered, head-mounted system that interfaced with MEMS microphones, an 8-channel DAC, an ESP32-based wireless module, and a custom battery module. While tailored for this specific application, the board’s flexible I/O and modular architecture making it ideal for audio, sensing, and real-time embedded tasks.

Figure 1: The PCB of the uDSP-Card with headphone line out, USB connector, the XCORE.AI processor and the interconnect.

Figure 2: System overview of the uDSP-Card.

Specification

The uDSP-Card is powered by the XMOS XU316-1024, a dual-core 800 MHz processor featuring 16 hardware threads and a dedicated vector unit for efficient real-time signal processing. Its architecture is derived from the XMOS reference design and development board XK-EVK-XU316¹, adapted for compact, low-power, portable applications.

Key Features

Dimensions: 60 mm × 30 mm (6-layer PCB)
Processor: XMOS XU316-1024 (dual-core, 800 MHz, 16 threads)
RAM: 128 Mb LPDDR1
Flash: 32 Mb QSPI
microSD card slot
USB Interface: Device (power + audio/data)
Line Output: Stereo via ESS ES9033 DAC
Expansion Header: 44-pin interconnect
- I²S (8ch)
- I²C / SPI
- PDM (8ch)
- Power input
Onboard Sensors:
- BMI323 IMU (accelerometer + gyro)
- BME280 EMU (humidity, pressure, temperature)

Figure 3: Block diagram showing the system architecture of the uDSP-Card and its interfaces.

Figure 4: 3D rendering of the front side of the uDSP-Card.

Figure 5: 3D rendering of the back side of the uDSP-Card.

Repository

hw_udsp-card: KiCAD project (schematic, PCB), board architecture, pinout, and renderings
sw_udsp-card: Example applications
lib_udsp_card_board_support`: XCORE board support and configuration files
lib_io_i2c: Individual C-based I²C library from xcore_iot
lib_io_i2s: Individual C-based I²S library from xcore_iot
lib_mic_array_192: Modified microphone array library for 192kHz
lib_xua_192: Modified USB audio library for 192kHz PDM support

References