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请问,如果我在P0_1口和地之间联了一个电阻,然后再vcc和P0_1之间接了一个电阻,然后读取P0_1的ADC值,这个ADC值和我计算的值差了很大,请问是不是在CC2540的内部,在P0_1内部有一个电阻,有没有具体的大小,谢谢了?
我考虑的是内部有一个保护电阻,但是经过多次计算值都有些差距。
还有就是如果有电阻,是不是其他口也有电阻并且这个阻值是相同的?
谢谢!
数据手册有描述,输入阻抗197K欧。
The ADC has an input impedance of approximately 197Kohms (resistance to ground - basically your pull-down resistor is in parallel with this 197K in the ADC).