板子上电后,程序无法启动,串口无数据输出,将一个负载(小马达)在电源和地之间接触一下,程序又跑起来了,串口有调试信息打印出来。但这种正常像似一种假象,因为再按按键时,串口无法输出键值。测试电源及各点电压都是好的,晶振的焊接也是好的,不然也不可能打印出调试信息,搞不明白是什么问题了?? 程序在别的板上已调试好,应该不是代码问题。 朋友们帮忙解答一下,感谢!
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超电压范围了吧。。。。。。
ABSOLUTE MAXIMUM RATINGS(1)
MIN MAX UNIT
Supply voltage All supply pins must have the same voltage –0.3 3.9 V
Voltage on any digital pin –0.3 VDD + 0.3, V ≤ 3.9
Input RF level 10 dBm
Storage temperature range –40 125 °C
All pads, according to human-body model, JEDEC STD 22, method A114 2 kV
ESD(2)
According to charged-device model, JEDEC STD 22, method C101 500 V
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating
Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) CAUTION: ESD sensitive device. Precaution should be used when handling the device in order to prevent permanent damage.
RECOMMENDED OPERATING CONDITIONS
MIN MAX UNIT
Operating ambient temperature range, TA –40 125 °C
Operating supply voltage 2-3.6 V
BR. Albin