Stellaris ARM Cortex-M3 MCU with Ethernet — what this part is
The LM3S6100-IBZ25-A2: The LM3S6100 is a 32-bit ARM Cortex-M3 microcontroller from the Stellaris 6000 series, clocked at 25 MHz with 64 KB of Flash and 16K x 8 of SRAM.
The 25 MHz Cortex-M3 core delivers roughly 25 DMIPS, enough to handle a Modbus TCP stack, a PID loop, and local I/O scanning in a single cycle. For applications that need faster protocol parsing or tighter loop times — say, a multi-axis stepper controller — a higher-speed sibling in the Stellaris family would be the correct fit. At this clock rate, the part sits comfortably in the mid-range of the Cortex-M3 performance band, trading throughput for lower dynamic power draw on a 2.25 V to 2.75 V supply.
Texas Instruments has marked the LM3S6100 as obsolete.