The USB module on TM4C123x MCUs supports three modes of operation: Host mode, Device mode and On-The-Go mode. The Host mode allows TM4C123x MCUs to interact with USB devices such as flash drives. Host mode allows the use of a USB mouse/keyboard as an input device to TM4C123x MCUs. Host mode also allows firmware updates to the MCU via flash drives, eliminating the need of a PC altogether by using the USB device firmware upgrade class. Device mode allows TM4C123x MCUs to connect to USB hosts such as computers. The MCU can be powered over the USB bus, eliminating the need for an external power supply. When the MCU is in Host mode, it allows PC side applications to perform firmware updates over the USB OTG mode. OTG modes facilitate dynamic switching between the host and device modes. The USB connector on the TI evaluation kit can be used to connect both the host and device cables.