Emcraft Systems STM32F4 SoM and Starter Kit Run uCLinux From On-Chip Flash

Emcraft has recently announced a new system-on-module based on STMicro STM32F437 Cortex M4 micro-controller, as well as a starter kit based on the module that can run uCLinux directly from STM32F437’s 2MB on-chip flash, allowing a faster boot time, and AFAIK, this is the only Linux-ready STM32 platform available on the market.

STM32F437 SoM

Here are the specifications of Emcraft Systems SOM-STM32F4:

  • MCU – STMicro STM32F437 Cortex M4 @ 168 MHz with 256KB RAM and 2MB flash
  • External Memory – 16MB PSRAM
  • External Storage – 16MB NOR Flash
  • Ethernet PHY (Optional)
  • Connectors – 2x SoM Connectors with access to I/Os: USB, Ethernet, I2C, SPI, UART, LCD I/F, ADC, DAC, GPIO…
  • Dimensions – 30 mm x 46 mm
Emcraft SOM-STM32F4 Block Diagram

To speed-up development and for evaluation, the company also provides a starter kit composed of the STM32F4 SoM, and a baseboard (SOM-BSB-EXT) with the following main features:

  • USB interface using USB-UART bridge connected to UART of the STM32F4
  • 10/100 Ethernet interface and RJ-45 connector
  • USB OTG Interface and mini-USB connector
  • Standard 20-pin ARM JTAG interface
  • User LEDs and push-button
  • Unused STM32F4 signals available on a breadboard area.
  • Dimensions – 100 x 70 mm

A mini-USB cable is also provided for power and serial console access.


Emcraft provides a uClinux BSP for STMicro STM32F2/F4 MCUs, with full source code, and no royalty for both U-Boot and uClinux. All STM32F4 systems-on-module come pre-loaded with uClinux and U-Boot.

As I mentioned in the introduction, the kernel fits into the on-chip flash which allows very fast boot time. For instance, a Linux configuration with Ethernet and full TCP/IP stack enabled comes up in just 1 second, from power-on to a point where TCP/IP is fully configured and shell commands can run, that compares to about 2 seconds on Freescale K70. Boot times close to 500ms are also possible without the networking stack. You can watch the video below to see this fast boot, as well as networking capabilities (ping, ntp, telnet, http server, and nfs mount).

The company also explains that overall performance in better as the entire kernel runs from the fast zero wait-state on-chip Flash, including core kernel, TCP/IP stack, device drivers, etc…

Emcraft System STM32F4-SoM is available for as low as $41 per unit (no Ethernet PHY configuration) for 1K orders, and If you want to give Linux a try on STM32, you can get the starter kit for $159. Further information, including software and hardware documentation, is available on Emcraft Systems’ STM32F4 page.

Disclosure: This post has been sponsored by Emcraft Systems.

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4 Replies to “Emcraft Systems STM32F4 SoM and Starter Kit Run uCLinux From On-Chip Flash”

  1. 41 USD @ 1k units ? A carambola 2/aria g25/locux for ex cost much less at single qty and have higher performance.

    But im still curious where such a SoM fits in ? What will be potential targeted applications for such a SoM .

  2. Is this board especially power efficient or something? Because at those prices you can get boards with a much more powerful Cortex-A8/A9 and 512MB/1GB of RAM that can run full Linux.

  3. @Vikas
    I think some people upgrade their designs from 8-/16-bit to Cortex Mx processor, and in some cases it might make sense to run uClinux, Power consumption should be lower than ARM9, ARM7., but I don’t know details about that.

    @Ian Tester
    I agree that for hobbyists the starter kit price is not very competitive compared to more powerful solutions, but I think the target market is different. More powerful Android/Linux boards will sell in at least thousands of units, even more for the like of Raspberry Pi, or to a lesser extend Beaglebone boards (Nearly 25,000 BBB have been sold in just over one month). I believe Emcraft mainly sells their starter kit to customers who plan to use their SoM in their designs, so price is not as critical as hobbyist boards, and they may only sell a few hundreds, if not less.

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