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目前上电输出脚是低电平，应该是有问题的
输出用来点灯，灯是低电平点亮，导致上电瞬间灯亮，用安世的类似芯片没这个问题
上电瞬间3.3V还没有，帮忙看看什么问题
您好，
SN74HC164是移位寄存器，TI 的寄存器在通电时没有默认状态，在通过时钟脉冲使数据输出之前或者通过CLR置低电平之前，输出处于“未知”状态。
具体见FAQ：[FAQ] What is the default output of a latched device? (Flip-Flop, latch, register)
