msp430上电后引脚输出什么电平

POR（上电复位Power On Reset）信号产生之后，系统的初始状态为：
1、RST/NMI引脚被设置为复位模式；
2、I/O引脚被转换为输入模式；
3、状态寄存器复位；
4、看门狗定时器进入到看门狗模式；
5、程序计数器PC指向复位向量的地址（0FFFFH）。

After a POR, the initial MSP430 conditions are:
The RST/NMI pin is configured in the reset mode.
I/O pins are switched to input mode as described in the Digital I/O chapter.
Other peripheral modules and registers are initialized as described in their respective chapters
manual.
Status register (SR) is reset.
The watchdog timer powers up active in watchdog mode.
Program counter (PC) is loaded with address contained at reset vector location (0FFFEh).
vectors content is 0FFFFh the device will be disabled for minimum power consumption.

第二行，I/O在上电后是输入状态，因此电平是不确定的