Keyestudio KS4028 Manual page 338

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Initial signal The microprocessor pulls down the data bus(SDA) for at
least 18 ms (less than 30 ms)
Response The sensor pulls down the data bus (SDA) 83 μs, and then
signal pulls up 87 μs to respond to the initial signal of the host.
The humidity high-bit is the humidity integer part of the
humidity data, the humidity low-bit is the humidity fractional part of
the data.
The temperature high-bit is the temperature integer part of
the data, the temperature low-bit is the temperature
temperature fractional part of the data. And the temperature low bit8 is 1,
which indicates the negative temperature; otherwise the
positive temperature.
Check bit Check bit = humidity high bit + humidity low bit+
temperature high bit + temperature low bit
Overall Communication Process：
After the user host (MCU) sends a start signal, the DHT11 is converted from
the low consumption mode to the high one. After the start signal is
completed, the DHT11 sends the 40bit data, triggering an information
collection. The signal transmission is shown in the figure.
Single-bus data format
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