The maximum clock frequency that can be used with the internal oscillator is 12 MHz. However, it's recommended to use a crystal oscillator or an external clock source for more accurate and stable clocking.
The pin multiplexing can be configured using the PINSELx registers. Each peripheral function has a specific pin multiplexing setting, which can be found in the datasheet. The PINSELx registers need to be programmed accordingly to enable the desired peripheral function on a specific pin.
The maximum current that can be sourced or sunk by the GPIO pins is 4 mA. However, it's recommended to limit the current to 2 mA to ensure reliable operation and to prevent overheating.
To use the ADC in differential mode, the ADCn_CFG register needs to be configured to select the differential input pair. The ADCn_CNT register is used to select the gain and the ADCn_DAT register is used to read the converted value. The differential input pair can be selected using the ADCn_CFG register.
The minimum voltage that can be used to power the device is 1.8 V and the maximum voltage is 3.6 V. It's recommended to use a voltage regulator to ensure a stable power supply within this range.
LPC11U68JBD100E datasheet
by NXP Semiconductors
