20 MHz Cortex-M3 with 16 KB Flash — what the memory budget means
This is a 32-bit ARM Cortex-M3 core clocked at 20 MHz, from the Stellaris 300 series. The 16 KB on-chip Flash and 2 KB SRAM are the hard limits for your firmware image and runtime data. That 2 KB SRAM disappears fast once you add a modest stack, a few global buffers, and the peripheral DMA descriptors — so plan for a lean, interrupt-driven architecture rather than a fat RTOS with large frame buffers.
The peripheral list includes a 3-channel 10-bit ADC, PWM outputs, a watchdog timer, and a brown-out detect/reset — enough for sensor readout, simple closed-loop control, and supervisory monitoring.
Package and first-power checklist
Supply range is 3.0 V to 3.6 V nominal — a single 3.3 V rail works. The internal oscillator means you can bring up the core without an external crystal, though the UART baud rate accuracy will depend on the internal RC calibration. SWD debug interface is available on the standard two-pin header for firmware development.