16 MHz, 2 KB Flash, 256 B RAM — sizing the MSP430G2253IPW20R for your firmware
Its program memory is 2 KB of Flash and it carries 256 x 8 bytes of RAM — enough for a single sensor node, a simple control loop, or a serial bridge, but too tight for a USB stack or a multi-threaded RTOS. The 8-channel 10-bit ADC (8x10b) handles analog inputs directly, saving an external converter.
Peripherals and I/O — what connects on the 20-TSSOP
Sixteen general-purpose I/O lines are available on the 20-TSSOP package (0.173" body width, 4.40 mm). The peripheral set includes a brown-out detect and reset (BOR), a power-on reset (POR), a DMA controller, a PWM timer, and a watchdog timer (WDT). The internal oscillator is on-chip, so no external crystal is needed for basic operation, though one can be added for tighter timing.