FRAM instead of Flash — what that changes in the BOM
FRAM writes at near-SRAM speed without an erase cycle, so you can treat it like a nonvolatile data buffer — useful for logging sensor readings or storing configuration parameters without wearing out the memory. The 16 MHz clock is enough for UART/SPI/I²C protocol handling and moderate sensor fusion loops.
31 I/O and the peripheral set — what connects where
With 31 general-purpose I/O lines in a 38-TSSOP package, you get enough pins for a small keypad, a character LCD, and a few sensor interrupts alongside the serial interfaces. The on-chip peripherals include a 12-channel 12-bit ADC, brown-out reset, POR, DMA, PWM, and a watchdog timer.