It can be tempting to choose the most powerful microcontroller. A better approach is to begin with the system requirements.

Start with a list of connections

Write down every device: motors and their drivers, buttons, sensors, displays and communication modules. Identify which connections use GPIO, PWM, ADC, I²C, SPI or UART.

Check the real constraints

  • Voltage: Is the board a 3.3 V or 5 V logic device? Are the peripherals compatible?
  • Pins: Do you have enough suitable pins after reserving communication buses?
  • Timing: Will the controller manage motor commands and sensor reading with acceptable latency?
  • Development: Are documentation and debugging tools available?

A good engineering habit

Build a pin table and a block diagram before purchasing components. Reserve a few spare pins for iteration, and document the power supply separately from the signal connections.