128 bytes of RAM — the tightest constraint on the BOM
The MSP430F2101IPW: The 128 x 8 RAM (128 bytes) limits stack depth, interrupt nesting, and active variables. Designs buffering sensor readings or running simple timed loops fit within 128 bytes.
On-chip peripherals for standalone operation
The MSP430F2101IPW includes a brown-out detect/reset (BOR), power-on reset (POR), a PWM timer, and a watchdog timer — enough to run a self-contained control loop without external supervisor ICs. The slope A/D converter provides a basic analog-to-digital conversion path for slow signals (temperature, battery voltage, potentiometer position) using an external resistor and capacitor.