Core and memory — what the 50 MHz Cortex-M3 carries
The LM3S1538-EQC50-A2T: The Cortex-M3 core delivers a balance of DSP-friendly instruction throughput and deterministic interrupt response — the 50 MHz ceiling is the practical limit for the flash wait-state profile, not the core itself. On-chip memory is split between 96 KB of program Flash (96K x 8) and 64 KB of SRAM (64K x 8). The 64 KB RAM leaves headroom for a moderate application stack plus a real-time OS footprint; the Flash is sized for control-loop firmware with a small bootloader partition.
The connectivity block includes I²C, SPI, SSI, UART/USART, IrDA, and Microwire — covering most sensor and actuator bus requirements — plus a Quadrature Encoder Interface (QEI) for motor-feedback loops. On-chip peripherals include a brown-out detect/reset, POR, PWM outputs, and a watchdog timer. An 8-channel 10-bit ADC handles analog inputs without an external converter.
Texas Instruments lists the LM3S1538-EQC50-A2T as Obsolete. For a BOM line that already carries this MPN, the only viable procurement channel is independent surplus and excess inventory. Each reel is lot-specific; traceability and date-code consistency are confirmed at quote time. No pin-compatible drop-in replacement exists from TI — a board spin is required to migrate to a current-generation MCU.