这两天用MSP430F5438A做一个低功耗项目。关于怎么尽可能的降低功耗，想请教下诸位大神。在数据手册上看到这么一段：

Unused I/O pins should be configured as I/O function, output direction, and left unconnected on the PCboard, to prevent a floating input and reduce power consumption. The value of the PxOUT bit is don't
care, since the pin is unconnected. Alternatively, the integrated pullup/pulldown resistor can be enabled by
setting the PxREN bit of the unused pin to prevent the floating input.


也就是说对没有使用的io口 要设置为输出  输出值不用在意，设置PXREN，也就是内部上下拉电阻，这样可以阻止悬浮电流。问题是PXREN具体改怎么设置？设置为多少？



此帖出自小平头技术问答