The TI Stellaris LM3S102-ERN20-C2T is a 32-bit ARM Cortex-M3 single-core microcontroller running at 20 MHz, with 8 KB of Flash and 2 KB of RAM. It belongs to the Stellaris ARM Cortex-M3S 100 series and targets small embedded control tasks — think sensor polling, serial protocol bridging, or simple motor commutation.
20 MHz and 8 KB Flash — sizing the control loop
The 20 MHz core clock with a single-cycle multiply puts this part in the small-control-loop tier. The 8 KB Flash holds roughly 2,000 to 3,000 instructions of compiled C code, so the firmware needs to be lean: no RTOS, no heavy libraries. The 2 KB RAM (organized as 2K x 8) is the tightest constraint — a single 1 KB buffer eats half of it. If your application fits that memory envelope, the part is a clean fit; if you are already bumping against the linker map, this is not the MCU to grow into.
The LM3S102-ERN20-C2T carries an official lifecycle status of Obsolete. TI has ended production; there is no last-time-buy window still open. This part is no longer available through the factory-authorized channel. Availability is intermittent and depends on what stock remains in distribution channels worldwide. Sourcing is handled on a quoted-to-order basis — each lot is verified for authenticity and date code before it ships.
28-SOIC — rework-friendly footprint
The 28-SOIC wide-body package (0.295-inch body width, 7.50 mm) is one of the most rework-friendly MCU packages in production. The 1.27 mm pitch leaves room for a fine-tip iron or hot-air nozzle to hit each pin without bridging. The leads are gull-wing, so visual inspection of the solder joint is straightforward. No exposed thermal pad underneath, so you do not need a stencil or a reflow profile for the pad.