80 MHz Cortex-M3 — memory budget and peripheral set
The LM3S1D26-IQR80-A2 is a 32-bit single-core ARM Cortex-M3 MCU clocked at 80 MHz from the Stellaris series. On-chip memory breaks down as 512 KB of flash for firmware and bootloader, plus 96 KB x 8 of SRAM for data buffers and stack — enough for a modest RTOS with a few protocol stacks. Peripheral integration includes DMA, PWM, WDT, brown-out detect, and POR, which reduces the external supervisor and glue-logic count. Connectivity covers I²C, SPI, SSI, UART/USART, LIN, IrDA, and Microwire — the UART set alone handles multi-drop RS-485 or Modbus on a factory floor. The 8-channel 12-bit ADC brings analog measurement on-die; the internal oscillator saves the crystal BOM line for applications that tolerate ±1% accuracy over temperature.
Industrial-temperature qualification and supply voltage
An enclosure sitting on a hot factory floor or a rooftop telecom cabinet stays inside the operating envelope without active cooling. That demands a regulated rail — a standard 1.2 V LDO with ±2% tolerance sits inside the band; a 1.8 V rail fed through a divider does not. The I/O bank tolerance is not listed, but the narrow Vdd range is the tighter constraint for the board designer.
Texas Instruments has marked this part obsolete. For a BOM that requires this exact part number, the procurement path is spot-market sourcing. A board spin to a current Cortex-M4 or M0+ from the same package family is the long-term migration option.
64-LQFP footprint — board layout constraints
Housed in a 64-LQFP with a 10x10 mm body. The 0.50 mm pitch demands controlled impedance traces if any high-speed serial interfaces (SPI at 80 MHz) are routed to the edge — the peripheral set includes SSI and UART, so 2-layer boards are viable for low-speed I/O but 4-layer is safer for the core clock.