The Texas Instruments LM3S6420-IQC25-A2T is a 32-bit ARM Cortex-M3 MCU from the Stellaris® 6000 series, clocked at 25 MHz with 96 KB of Flash program memory and 32 KB of RAM. The 46 general-purpose I/O lines and on-chip peripherals (brown-out detect, POR, PWM, watchdog timer) cover the typical sensor-actuator interface needs of a mid-complexity embedded controller.
At 25 MHz the Cortex-M3 executes single-cycle multiply and hardware divide, so a PID loop or Modbus packet handler finishes in deterministic time. This is not a high-throughput DSP core; it is sized for event-driven control where the Ethernet port carries occasional configuration frames or status reports, not streaming data. The 96 KB Flash holds a moderate firmware image with a TCP/IP stack and application logic; the 32 KB RAM leaves room for a few hundred bytes of packet buffer and local variables.
Lifecycle: obsolete — sourcing reality
The LM3S6420-IQC25-A2T is obsolete per the manufacturer. No direct pin-compatible replacement from TI's current Stellaris or Tiva-C portfolio is listed in the evidence.