TI中文支持网三态，INPUT上拉，OUTPUT LOW，哪个功耗最低？
Viki Shi：
Unused I/O pins should have a defined level and not be left floating. One way to do this is to leave the pin unconnected and configure the pin as a general purpose I/O input with pull-up resistor. Alternatively the pin can be configured as a general purpose I/O output
user1354758：
回复 Viki Shi:
其实我想知道 在关机情况下 IO设置成三态还是 output low 功耗更低，官方的参考是 output low
Yue TANG：
回复 user1354758:
output low是最优
Ideally, each GPIO pin will be unconnected, and therefore no leakage of current will occur. In real case, as with most boards, many of the GPIO pins are connected to peripheral devices, such as the LEDs, the buzzer, the accelerometer, and the buttons. To maximally reduce the current, all GPIO pins must be set to outputs at a low level.
