MKE04外接无源晶振，起振后用示波器测试EXTAL的波形。

[旭余朱]

MKE04外接8M无源晶体，起振后用示波器测试EXTAL的波形，发现对地只有1V。测量其它单片机，这个脚的电压比较高，之所以关注这个电压是因为晶体厂家说无源晶体起振点是1.3V，低了会振不起来。所以想问下这是否正常。除此之外，频率这些都是正常的。

MKE04 is connected to an 8M passive crystal. After the oscillation, test the waveform of EXTAL with an oscilloscope and find that it is only 1V to the ground.  When measuring other MCU, the voltage of this pin is relatively high. The reason for paying attention to this voltage is because the crystal manufacturer said that the starting point of the passive crystal is 1.3V.  So I want to ask if this is normal.  Other than that, these frequencies are normal.

[Robin_Shen]

Hi 旭余 朱,

由于晶振信号对于电容负载比较敏感，所以在测试晶振输出信号时，需要把探头拨到X10衰减档位，以减小测试引入的负载效应。

Please try to use the X10 oscilloscope probe.

Best Regards,

Robin

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[旭余朱]

感谢回复，已经用×10档位测试，频率正常，波形漂亮，就是峰峰值只有1V，不知道是不是正常现象

[Robin_Shen]

这和OSC_CR[HGO]设置也有关系，如果你设置Low-power mode则属于正常现象。

[旭余朱]

感谢回复，我用的是官方默认的时钟配置，刚看了下官方是用Low-power mode。请问高增益和Low-power mode是功耗上的区别吗，不在乎功耗的话，选择高增益可靠性是否会高些？