AM2302 data bus SDA output 40 data continue to output the low 50 microseconds into the input state,
followed by pull-up resistor goes high. AM2302 internal re-test environmental temperature and humidity data,
and record the data, the end of the test records, the microcontroller automatically into hibernation.
Microcontroller only after receipt of the start signal of the host wake-up sensor, into the working state.