Mid-range MCU selection : STM32

Christoph TackChristoph Tack wrote 10/22/2020 at 19:45 • 3 min read • Like

Blue pill

Nucleo 32

Why Nucleo32?

  1. Small, the 2x15pins fits in a 2x16 0.6" row spacing IC-socket (Digikey 2057-ICS-632-T-ND)
  2. Apparently pin-compatible to Arduino Nano.  To be confirmed.
  3. 3V3, which is easier to interface to other electronics than the 5V boards.
  4. Integrated ST-Link debugger.  Reduces the mess-o'-wires on your breadboard.
  5. Cheap <€10 from official sources (Digikey etc.)
  6. Good build quality, unlike the Chinese boards where you have to replace components that had the wrong value, are less-functional clones or that were otherwise unsuitable.
  7. A whole range of boards, with different MCUs.  Some low power, some good processing capabilities.
  8. Good documentation
  9. Supported by PlatformIO (Arduino and other frameworks).
  10. Smaller than Blue Pill, but less GPIO pins
  11. Arduino Nano footprint compatible
  12. STM32Fxxx
    variants not suited for low power.  They need the clock signal from the ST-Link, e.g. if the UART baud rate is greater than 9600baud.
  13. STM32Lxxx variants may be better for low power applications.  To be investigated.

It might not be low power because of the integrated debugger.  There might be ways to leave the debugger unpowered.  These boards lack wireless connectivity.

ST-Link firmware

The ST-link firmware must be upgraded to make the virtual COM-port (VCP) work properly.  The software to do this can be found on the ST-website.  This should be the first thing you do with the Nucleo32 boards.