Obsolete — sourcing reality for the BOM line
Texas Instruments has marked the LM3S1Z16-IQR50-C3T as Obsolete. Availability is lot-specific and confirmed at RFQ time — no stock-holding claim is made here.
50 MHz Cortex-M3 with 16 KB flash — what fits
The core is an ARM Cortex-M3 running at 50 MHz — this is a single-cycle multiply, hardware-divide, bit-banding core without the FPU overhead of the M4. The 16 KB on-chip flash and 6 KB SRAM mean the bootloader, RTOS kernel, and application stack must be budgeted tightly. The flash is not shared with a large TI boot ROM, so the full 16 KB is usable for the application image. 33 general-purpose I/O lines are brought out from the 64-LQFP package. The 10x10 mm body with 0.5 mm pitch is a standard four-layer-board footprint — the inner rows of the QFP fan out cleanly on a 4-layer stack without micro-vias.
Peripheral set and supply rails
The part integrates a 10-bit ADC with 8 multiplexed channels, a PWM module, a watchdog timer, and a DMA controller. The connectivity block covers I²C, SPI, SSI, UART/USART, IrDA, LINbus, and Microwire — enough serial interfaces for a sensor hub or a simple motor-control node without an external UART expander. The I/O ring runs from a separate supply; the datasheet's recommended operating conditions must be read for the I/O voltage tolerance. The internal oscillator eliminates the external crystal for the core clock, saving two pins and a pair of load capacitors. This covers most factory-floor and outdoor enclosure applications without requiring the extended-temperature screening of an automotive-grade part.