Cortex-M3 core with 50 MHz and 256 KB flash
The LM3S1816-IQR50-C5T: This puts it in the mid-range of the Stellaris 1000 family — enough flash for a full protocol stack plus application code, with the RAM split leaving room for moderate-sized data buffers without external memory.
33 general-purpose I/O lines are brought out on the 64-LQFP package. The peripheral set includes I2C, SPI, SSI, UART/USART, and IrDA for serial connectivity, plus a PWM module, DMA controller, and an 8-channel 10-bit ADC. Brown-out detect, POR, and a watchdog timer are integrated — no external supervisor needed for basic reset handling. The internal oscillator means the core can run without an external crystal for non-critical timing, though the UART baud-rate accuracy will depend on the internal RC tolerance.
Lifecycle reality — obsolete, sourced to order
Texas Instruments has marked the LM3S1816-IQR50-C5T as obsolete. No official successor or pin-compatible replacement is recorded in the Stellaris 1000 series — the Stellaris line was migrated to the Tiva-C family, but the package and pinout differ.