i.MX8M-Driven Pico-ITX SBC Features Dual-DSP Audio Module

By Eric Brown

Estone is launching an “EMB-2238” Pico-ITX board for audio and voice control applications that runs Linux on an i.MX8M and offers a dual-DSP audio hub and DAC, 40-pin GPIO, and optional PoE and second GbE.

Toledo, Ohio based Estone Technology (known for its former Habey brand) offers a variety of Linux-friendly Pico-ITX boards, including boards based on the i.MX6 (EMB-2230), i.MX6 UL (EMB2200) models, and Intel Cherry Trail EMB-2610. The company recently announced (via Electronics Weekly) an EMB-2238 board with the same 100 x 72mm form factor. The SBC builds on the audio strengths of NXP’s i.MX8M SoC with the help of high-end audio circuitry from Cirrus Logic.

 
EMB-2238
(click images to enlarge)The EMB-2238 uses the quad-core version of the 1.5GHz, Cortex-A53 equipped i.MX8M, which also includes a GPU and 266MHz Cortex-M4 chip. Estone provides a Yocto Project stack based on Linux kernel 4.9, Qt, and Wayland. It also supports Android 8.1.0.

Other i.MX8M Pico-ITX boards we’ve seen include Kontron’s dual-GbE pITX-iMX8Mand F&S Elektronik Systeme’s up to 8GB LPDDR4 armStone MX8M. There’s also a larger, 136.7 x 87mm Nitrogen8M SBC from Boundary Devices.

All these boards tap the i.MX8M’s extensive digital audio skills to varying degrees, but the EMB-2238 is even more focused on audio and voice control applications. It adds a Cirrus Logic CS47L24 smart codec module with a dual-core, 300-MIPS DSP and audio hub. The triple-DAC device offers a 115 dB dynamic range, an 8-192kHz sample rate, and Enhanced DRE processing (eDRE) for 121dB SNR.

 
EMB-2238 (left) and Cirrus Logic CS47L24 audio module block diagram
(click images to enlarge)The CS47L24 drives the EMB-2238’s dual digital MEMS microphone header, which features multi-mic noise suppression and acoustic echo cancellation (AEC). A 40-pin expansion header provides omni-directional, spatial 8-channel digital audio/DMIC inputs (SAI5) for the mic array, among other I/O including PCIe. Additional audio features on the SBC include a Class D, 2W mono speaker, an 8-channel digital input and output (SAI1), and SPDIF and QSPI audio interfaces.

The EMB-2238 ships with the Amazon AVS (Alexa Voice Service) Device SDK, as well as Sensory’s TrulyHandsfree wake word engine. It also supports the Snips AI voice control assistant, including support for off-line operation (see video demo farther below).

You can purchase the SBC with 2GB to 4GB LPDDR4, and a microSD slot and 8GB iNAND are also available. For communications there’s a WiFi/BT module and a GbE port with optional an Power-over-Ethernet (IEEE 802.3af) or PoE+ (802.3at) module that can also power an attached LCD panel. A separate option provides a second GbE port via a PCIe add-on card that also integrates a 9-36V DC input, GPIO, an ambient sensor, and an LED control for light bars.

 
Optional PoE (left) and GbE add-ons
(click images to enlarge)The EMB-2238 is equipped with a 4K-ready micro-HDMI port and HD-ready MIPI-DSI with optional 10.1-inch touch-panel. Other features include a MIPI-CSI camera interface, USB 3.0 OTG Type-C port, dual USB 2.0 host ports, and 2x internal USB interfaces.

The SBC provides a RS-232/RS-485 terminal block, RS-232 header, and the 40-pin header. A 5V DC header offers an alternative to the optional PoE and 9-36V input. The board also provides a watchdog and 0 to 60°C support. As usual with Estone, you get comprehensive documentation.

Specifications listed for the EMB-2238 include:

• Processor — NXP i.MX8M (4x Cortex-A53 @ 1.5GHz); Vivante GC7000Lite/GC7000VLX for OpenGL/ES 3.1, OpenGL 3.0, Vulkan, OpenCL 1.2 GPU; Cortex-M4 @ 266MHz
• Memory/storage:
  • 2GB to 4GB LPDDR4 RAM
  • 8GB iNAND flash
  • MicroSD slot
• Wireless — 802.11 b/g/n and Bluetooth 4.10 module (USB-based)
• Networking — GbE port with optional PoE; optional second GbE via PCIe add-on with GPIO, 9-36V input, LED control etc.
• Display/camera I/O:
  • Micro-HDMI port for up to 4096 x 216 0 @60Hz
  • MIPI-DSI (4-lane) for up to 1920 x 1200 and I2C-based support for LCD touchpanels
  • MIPI-CSI (4-lane)
• Audio/voice control I/O:
  • Class D 2W mono speaker
  • 2x HP out header
  • 8-channel digital in and out (SAI1) with 32-bit @ 384 kHz fs and TDM support
  • SPDIF, QSPI
  • Cirrus CS47L24 smart codec with 2x-core, 300-MIPS DSP with 3x DAC and audio hub with SoundClear Control
  • 2x digital MEMS mic header (via CS47L24) with multi-mic noise supp., AEC
  • Omni-directional spatial 8 ch. digital audio/DMIC inputs (SAI5) for mic array (via 40-pin)
• Other I/O:
  • USB 3.0 OTG Type-C port
  • 2x USB 2.0 host ports
  • 2x USB 2.0 headers
  • RS-232/RS-485 terminal block
  • RS232 header
  • 4x+ GPIO, 2x I2C for TP and MIPI CSI
• Expansion — 40-pin connector with PCIe x1, GPIO, font panel control, PoE, 8 ch. audio in etc.
• Other features — Watchdog timer; 10 to 15-year support longevity
• Power — 5V DC header or optional PoE or optional 9-36V input (GbE add-on)
• Operating temperature — 0 to 60°C
• Dimensions — 100 x 72mm; Pico-ITX form factor
• Operating system — Yocto Project (Linux kernel 4.9, Qt, Wayland); Android 8.1.0; ships with Amazon AVS and Sensory TrulyHandsfree Wake Word Engine

EMB-2238 Snips and AVS voice control demos
Further information

No pricing or availability information was provided for the EMB-2238 SBC. More information may be found at the Estone Technology EMB-2238 product page.

Estone Technology is demostrating the board at Embedded World in Nuremberg (Feb 26-28) at Hall 1 stand 1-129.

This article originally appeared on LinuxGizmos.com on February 15.

Estone Technology | www.estonetech.com

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