TI中文支持网正在用贵司的芯片开发产品，遇到如下问题：
只有底板能正常唤醒，采样，回复；但是与之级联的芯片不能正常工作；请问一下非底板的器件其VIO如何处理？不接可以吗？
补充：我们实际的电路是将Vio接到了Vp，但是现在经过测试Vp没有电压输出，请问有哪些原因呢？
Andrew Su：
杨工，
出最低一级的PL455外，其他的PL455的VIO通常是与VP相连的， 因为VIO 是给所有数字接口管脚 TX, RX, FAULT_N, GPIOn供电的电源，因此必须接， 如果VIO没有电，PL455将会关机：If VIO does not have power, the part holds in reset and enters shutdown after a short delay。
看起来你的问题是VP没有电。 VP的电源来自于外部的三极管 （由NPNB控制，与最高一级电芯相连），请参考EVM的电路。
VP Regulated OutputThe bq76PL455A power comes directly from the cells to which it is connected. Current draw is from the top andbottom of the n-cell battery assembly, so that current through each cell is the same. An integrated linearregulator utilizes an external NPN transistor (Zetex ZXTN4004K or similar) to generate a nominal 5.3-V rail onpin VP. VP is both a power input and the sense node for this supply. The NPNB pin controls the external NPNtransistor of the regulator. A capacitor or resistor-capacitor combination must connect externally from VP to GND,see Pin Configuration and Functions for details. VP must connect externally to VDIG and can optionally connectto VIO. Both of these connections are through series 1-Ω resistors and separately decoupled. This regulator isOFF in SHUTDOWN mode.
