Placing half of this value as a pullup to5V and half as a pulldown to ground gives a maximum bias resistor value of685 Ω for each of the two biasing resistors .
如将其值的一半接到5V电源做上拉电阻，将另外的一半拉接到地做下拉电阻，则各个节点的两边偏置电阻最大总共为685Ω。
Pullup your head off the floor , come up screaming .
用你的头去撞地板吧，来发出尖叫吧。
pullup