TM4C129x products have been designed to meet the requirements of a number of cost conscious home and industrial automation applications. To reduce the overall BOM cost, and required PCB foot print, Texas Instruments has designed the Ethernet Controller so that it can be clocked from the main oscillator. Only one 25 MHz clock source is required. It could be either an external crystal or a single-ended clock source to generate clock for the core, memory subsystem, and Ethernet Controller. This is a benefit as compared to the legacy products which required two separate crystals, one for the main oscillator, and another for the Ethernet Controller.