Designed by vasy_skral with jharwinbarrozo | Shared under CC BY 4.0

Original project on Flux: https://www.flux.ai/vasy_skral/stm32mp1-linux-card~kyo

WHAT IS THIS PROJECT ABOUT?

The STM32MP1 Linux Card is a compact Linux single board computer designed by vasy_skral, with jharwinbarrozo credited as a co-author on Flux. It is built around the STM32MP157FAC1 and combines the processor with DDR memory, a dedicated power management IC, USB and SD card interfaces, and the essential user controls. It is aimed at versatile embedded applications, and the design has been well received on Flux, with 13 stars and 25 forks.

A board like this is a real step up from a typical microcontroller project. It runs a full Linux operating system, so you can use standard software, drivers, networking and file systems on a board you can study and change yourself.

ABOUT THE STM32MP157F

The STM32MP157F is a microprocessor from STMicroelectronics with a combination of cores that is unusual at this size. It has two Arm Cortex-A7 cores running at up to 800 MHz, which run Linux, plus a separate Arm Cortex-M4 real-time core running at up to 209 MHz for timing-critical tasks. It also includes a 3D GPU, support for TFT and MIPI DSI displays, CAN FD, and secure boot and cryptography features. It supports external DDR memory of up to 1 GB.

This mix lets one chip handle both jobs that normally need two: a rich operating system for networking, user interfaces and applications, and a real-time core for motor control, sensors and other hardware that cannot wait for a scheduler.

HARDWARE DESIGN

• Processor: STM32MP157FAC1 (dual Cortex-A7 plus Cortex-M4)
• Memory: Micron MT41K256M16 DDR3L, 4 Gbit (512 MB)
• Power management: STMicroelectronics STPMIC1 PMIC, which generates the board's several supply rails and the DDR reference
• USB: USB-C connector, with ESD protection on the data lines
• Storage: microSD card slot
• Debug and programming: Tag-Connect TC2050 connector
• Boot control: boot-mode switches (BOOT0 and BOOT2) to select where the board starts from
• User controls: power key and reset buttons
• Real-time clock: 32.768 kHz crystal
• Board construction: six-layer (top, four inner layers, bottom)

A design like this is as much about layout as about parts: the DDR memory needs carefully routed, matched signal lines, and the processor needs many clean supply rails. The six-layer stack gives the room for that.

ASSEMBLY NOTE

The processor and the DDR memory both come in ball-grid-array (BGA) packages, so assembly needs a service with BGA placement and inspection capability. The layout also needs high-density manufacturing, so check the fabricator's capabilities before ordering.

MANUFACTURING FILES

The project is published ready for fabrication and assembly. It includes a complete Gerber set covering the top and bottom layers, all four inner copper layers, solder mask, solder paste, silkscreen and board outline, together with an Excellon drill file, an IPC-D-356 electrical test netlist and a pick-and-place CSV for automated assembly. Bills of materials are provided in formats prepared for several manufacturers, including a version optimised for PCBWay.

CREDITS AND LICENCE

Designed by vasy_skral (Flux), with jharwinbarrozo. The design is released under the Creative Commons Attribution 4.0 International licence (CC BY 4.0): https://creativecommons.org/licenses/by/4.0/

The STM32MP157 and STPMIC1 are STMicroelectronics products. All design work and credit belong to the original creators. Please visit the original Flux project, explore the design in full, and show the creators some support.