The maximum clock frequency of the TM4C1233E6PMIR is 80 MHz, but it can be overclocked to 120 MHz with some limitations.
The pin muxing on the TM4C1233E6PMIR can be configured using the Pin Mux Utility tool provided by Texas Instruments, or by writing code to configure the GPIO registers directly.
The main difference between the TM4C1233E6PMIR and the TM4C123GH6PMI is that the TM4C1233E6PMIR has a smaller package size (LQFP48) and fewer pins, while the TM4C123GH6PMI has a larger package size (LQFP64) and more pins.
Yes, the TM4C1233E6PMIR can be used with an external crystal oscillator. The device has an internal oscillator, but it can also be driven by an external clock source.
The TM4C1233E6PMIR can be programmed using a variety of tools, including the Keil µVision IDE, IAR Embedded Workbench, and the Texas Instruments Code Composer Studio (CCS).