P&E不能download，MC9S08DZ48 amp, download

我现在用P&E烧写目标板，MCU型号是MC9S08DZ48，4M晶振，5V供电。这板子我有n块，手头有2块不能download代码。每次下载时都会提示：
USB HCS08/HCS12 MULTILINK detected - Flash Version 5.79
USB HCS08/HCS12 MULTILINK detected - Flash Version 5.79
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
USB HCS08/HCS12 MULTILINK detected - Flash Version 5.79
Device is 9S08DZ48.
Mode is In-Circuit Debug.
Windows NT detected.
USB HCS08/HCS12 MULTILINK detected - Flash Version 5.79
Frequency change to ~0hz.
Frequency change to ~0hz.
USB HCS08/HCS12 MULTILINK detected - Flash Version 5.79
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.
Frequency change to ~0hz.

Error: Can not enter background mode

BDM电路连接和晶振电路都没有问题，当将P&E插入板子后，我测得Reset引脚为3V，BKGD引脚为3V，正常情况下为5V才对。
有没有高手遇到过类似问题？希望给些指点，谢谢了。

片子有没有烧坏？
P&E可能工作在3V,而你的芯片工作在5V系统。
显然此时电平不匹配，你需要用电平转移电路，或者把P&E调到5V接口电平。

好帖子，路过也不得不顶一下！！！！