The maximum clock frequency that can be used with the internal oscillator is 72 MHz.
To configure the pin multiplexing for I2C, set the PINSEL0 register to select the I2C function for the desired pins (e.g. P0.27 for SCL and P0.28 for SDA).
The minimum voltage required for the ADC to operate correctly is 2.4V.
To enable the BOD feature, set the BODCTRL register to enable the BOD and set the desired voltage threshold.
The maximum current that can be sourced or sunk by a GPIO pin is 4mA.