Datasheet

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DHT20 Data Sheet
Version:V1.0 —— May 2021
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Table 8. Timing characteristics of I²C fast mode digital Inputs / outputs
The meaning is shown in Figure 9. Unless otherwise noted
7 Sensor Communication
DHT20 uses standard I²C protocol for communication. For information about the I²C protocol other than the
following chapters, please refer to the following website: www.aosong.com provides a sample program for
reference.
7.1 Start the Sensor
The first step is to power up the sensor with the selected VDD supply voltage (range between 2.2V and 5.5V). After
power-on, the sensor needs less than 100ms stabilization time (SCL is high at this time) to reach the idle state and
it is ready to receive commands sent by the host (MCU).
7.2 Start/Stop Sequence
Each transmission sequence starts with the Start state and ends with the Stop state, as shown in Figure 10 and
Figure 11.
Figure 10. Start transmission status (S)
When SCL is high, SDA is converted from high to low. The start state is a special bus state controlled by the master,
indicating the start of the slave transfer (after Start, the BUS is generally considered to be in a busy state).
Figure 11. Stop transmission state (P)
When SCL is high, the SDA line changes from low to high. The stop state is a special bus state controlled by the
master, indicating the end of the slave transmission (after Stop, the BUS is generally considered to be in an idle
state).