128 KB FRAM — no erase cycles, no wear limits
The MSP430FR69891IPZR: FRAM writes at bus speed and retains data without a battery. For a design that logs sensor data or updates firmware over the air, this eliminates the erase-page latency and endurance ceiling of Flash. The 2K x 8 RAM handles stack and scratchpad; the FRAM holds both code and non-volatile data in a single unified memory map.
Peripherals and I/O count
83 general-purpose I/O lines give room for a parallel LCD, keypad matrix, and multiple sensor interrupts. The internal oscillator frees a crystal for the main clock — one less BOM line.