20 MHz Cortex-M3 — the right tier for sensor and control loops
The LM3S102-IGZ20-C2T: This is the entry-level performance tier in the Cortex-M3 lineup — it handles sensor polling, serial protocol bridging, and simple PWM control loops without the cost or power of a 100 MHz part. The 18 general-purpose I/O pins and the peripheral set (I²C, SPI, UART/USART, Microwire, SSI) map directly to common embedded tasks: reading a temperature sensor over I²C, driving a small character LCD via SPI, or managing a brushed DC motor with the PWM and watchdog timer.
Memory budget — 8 KB Flash, 2 KB SRAM
With 8 KB of program Flash and 2 KB of SRAM, firmware must be lean. This is adequate for a single-protocol sensor node or a simple state machine, but leaves no room for a full RTOS heap or a TCP/IP stack. The 2 KB SRAM is shared with stack and variables — budget carefully if you are adding a circular buffer or a moderate lookup table. The Flash is rated for 100k erase/write cycles typical for this process node, sufficient for field-updateable firmware if wear-leveled.
The supply range of 3.0 V to 3.6 V is a single 3.3 V rail — no dual-voltage domain needed.