128 KB flash, 16 KB RAM, 25 MHz — the memory and speed envelope
The MSP430F5256IZQE is a 16-bit MSP430 CPUXV2 microcontroller from the MSP430F5xx series, running at 25 MHz. On-chip memory is 128 KB of flash and 16 KB of RAM — enough for moderate sensor-fusion or communication-stack firmware without external memory. The 53 general-purpose I/O lines connect to the peripheral set: I²C, SPI, UART/USART, plus IrDA and SCI. Brown-out detect, POR, DMA, and a watchdog timer are integrated on die.
80-ball BGA MICROSTAR JUNIOR — board-fit reality
The package is an 80-VFBGA, supplier device package 80-BGA MICROSTAR JUNIOR measuring 5x5 mm. The 0.50 mm ball pitch demands a controlled-impedance PCB with microvia fan-out — a two-layer board will not break out the inner rows cleanly.
Texas Instruments lists the MSP430F5256IZQE as Obsolete. For a BOM line that depends on this exact package and memory map, the only path is the surplus market. A pin-compatible replacement within the MSP430F5xx family may exist, but no direct cross-reference is published by TI.