The maximum clock frequency of the TM4C123AH6PMIR is 80 MHz, but it can be overclocked to 120 MHz with some limitations.
The pin muxing on the TM4C123AH6PMIR 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 TM4C123AH6PMIR and the TM4C1294NCPDT is that the TM4C1294NCPDT has more flash memory (1MB vs 256KB) and more peripherals, such as a USB OTG interface and a CAN interface.
The ADC on the TM4C123AH6PMIR can be used by configuring the ADC registers, enabling the ADC clock, and then reading the ADC conversion results from the ADC FIFO. The ADC can be triggered by a software trigger or by an external trigger signal.
Yes, the TM4C123AH6PMIR can be used with an operating system like Linux or FreeRTOS. Texas Instruments provides a range of software development kits (SDKs) and drivers that support these operating systems.