In addition to PE.8 - PG.13 and PF.0 - PN.2, V_DD provides all GPIO operating voltage. In accordance with the needs of the application, the V_DD voltage range can be set as 2.5V - 5.5V.
For PE.8 - PE.13, the GPIO operating voltage is exclusively supplied by V_DDIO (Voltage Adjustable Interface). In accordance with the characteristics of peripheral devices, the V_DDIO voltage can be independently powered and the range can be set as 1.8V - 5.5V. Specifically, the PE.8 - PE.13 can be set as external pins of UART, SPI or I²C.
For PF.0~PF.2, the GPIO operating voltage is supplied by V_BAT. The RTC operating voltage is also supplied by V_BAT. In accordance with RTC power requirements, the voltage supplied from the external to V_BAT must be 2.5V - 5.5V. If the application contains the RTC and V_BAT external battery, PF.0 and PF.1 must be connected to a 32 kHz crystal. It is recommended to set PF.2 to high impedance input mode at this time to avoid generating output current and accelerating battery consumption.

Products:	Microcontrollers ,Arm Cortex-M4 MCUs ,M451 Base Series ,M451M Series ,M452 USB Series ,M453 CAN Series
Applications:
Function:	Peripherals,I/O,GPIO

FAQ

How is GPIO power in the NuMicro™ M451 series divided? Issue Date：2015-04-23