For an existing production BOM that already qualifies this part, NRND means the manufacturer may still support it for a time, but new designs should not start with it. The official status is not full discontinuation—yet—but the clock is running.
50 MHz Cortex-M3 – what the speed rating drives
The core runs at 50 MHz, a 32-bit ARM Cortex-M3 single-core processor from the Stellaris® ARM® Cortex®-M3S 1000 series. That clock rate sets the throughput for control loops, protocol processing, and real-time tasks. For a design that needs moderate compute—say a motor control loop with sensor feedback or a protocol bridge—50 MHz is a solid mid-range point.
Sourcing posture for the LM3S1968-IQC50-A2T
For a production line that cannot requalify a new MCU, this is the channel to fill the gap.