St have a good series of MCU’s and I have stuck with F405 for a while. But, I just discovered G474RE, G484RE, G484CEm G491CE etc. This series is very similar to F405, but contains a lot of extras for a lower price. Also some of the MCU’s are LQFP48, but it is still a M4 ticking at 170Mhz.

Using G474RE as an example:

  • M4 w/512KbFlasg, 128Kb SRAM, 170Mhz
  • Math accelerators (Geometri and Filters)
  • 16 ch DMA
  • 5 x 12 bit ADC w/16bit oversampling.
  • 7 x 12 bit DAC
  • 7 x Analog comparators
  • 6 x Op amps
  • Loads of PWM signals.
  • 17 timers
  • 3 x FDCan
  • 4 x 1Mbit I2C
  • 6 x UART
  • 4 x SPI
  • USB
  • and much more…

G484RE holds crypto in addition, both G474 and G484 also have 48 pin versions. ST is also very good in backward compability so these MCU’s are a drop-in replacement on my F405 designs I assume. The addition of math accelerators and analogue components makes this a very good candidate for motor controllers – but, that said – these MCU’s are very fast as is without the accelerators.

FD CAN in special interest me as IPC backbone on a stack. It is fast and with higher payload than it’s HS version. FD CAN seems very similar to ordinary CAN with the exception of up to 64 byte payloads. I fail to read if max speed is increased, but I assume so. What these lacks is a bit less Flash and no Ethernet compared to F407 etc. But, I can live with that.

Ethernet on one of these MCU’s can easily be added through a Wiznet chip for normal usage. Usage of Ethernet often also requires web pages and I preffer to offload that to another MCU anyway. A fronend Linux like Raspberry PI is excellent as Web Server and gateway to real-time systems. The same goes for user interface – GUI/HMI, but that’s my preferences.

I have ordered kit’s to play with many of the new ST MCU’s. Ordering MCU’s at this time is almost impossible as it is very long manufacturing delays all-over due to the aftermath of the pandemic. I order ST kits from digikey and just add sufficient kits so I get free P&P – so far this has worked great with packages arriving after 2-3 days. Attempting to order anything from China these ways are also difficult due to prices. Hopefully the world will normalize the next 12 months – fingers crossed.

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