Engineer Jay Carlson has taken advantage of OSH Park's upcoming six-layer offering by designing a compact, breadboard-friendly, Linux-compatible single-board computer based around the NXP i.MX6 ULZ system-on-chip — and with support for Wi-Fi and Bluetooth SDIO modules: the mxiot.
"mxiot is a low-cost hardware prototyping platform to help you explore switching small IoT projects from bare-metal to a secure-boot-capable Wi-Fi/BT-connected Embedded Linux system capable of running rudimentary C/C++," Carlson explains, "as well as applications written in almost any modern language or application framework (like Qt, Rust, Ruby, Python, Node.js, or .NET Core)."
"I've always wanted to do a small-form-factor embedded Linux breakout board, but it felt silly laying down a beefy part without ethernet or any of those big parallel multimedia interfaces available. The ULZ has none of that, so it's a guilt-free form factor for the part. This one supports standard 40-pin SDIO WiFi/BT modules, so you'll have options for 802.11n or ac, and BT 4.0-5.0."
The board is laid out across six layers — to assist with keeping the overall footprint down, while also making routing easier and allowing the design to be completed in a matter of hours — and has been produced in prototype form on a test panel, ahead of the launch of a six-layer PCB production service at OSH Park.
The mxiot includes the iMX6 ULZ with a single 900MHz Arm Cortex-A7 core, three UARTs, two I2C peripherals, SPI with two chip-select signals, I2S, four PWM outputs, two USB ports, an RGB LED, a Texas Instruments TLA2024 offering four 12-bit analogue inputs, QSPI flash with boot support, the builder's choice of SDIO Wi-Fi and Bluetooth module, and the DRAM module and microSD socket necessary to boot Linux.
Carlson received the test boards earlier this month, and has been working on bring-up and validation; following successes on both fronts, he has released the design on GitHub under the permissive Creative Commons Attribution-ShareAlike 4.0 license.