Memory sizing and the BOM decision
With 512 KB Flash and 256 KB SRAM, this MCU sits in the mid-to-upper density tier of the Tiva C family. The 6 KB EEPROM eliminates an external serial EEPROM for calibration constants or network parameters, saving board area and a BOM line. The 90 general-purpose I/O in a 128-TQFP package give enough pins to drive a parallel LCD, a memory-mapped FPGA, or a bank of opto-isolated inputs without a port expander.
An internal oscillator is available, but for Ethernet timing an external 25 MHz crystal is typical.