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图 14

diagrams

Reference sequence:

refer to the single bus-processing example.

◎Single bus description

DHT12 A simplified single-bus communication. That only a single bus cable, system of data

exchange,Control is done by a single bus communication. Devices (hosts) through a drain or a

three-State port is connected to the data cable to allow device does not send data will be released

when the bus, while letting the other device uses the bus; usually require add-ins a single bus

around 4.7KΩPull-up resistor, so that when the bus is idle by default high State. Because they are

the master-slave relationship, only when the host calls the sensor, the sensor responds, so host

access must be strictly followed during single bus timing, timing disorder if will not be able to

correctly read data of temperature and humidity.

◎Single bus transfer data definitions

SDA PIN for client hosts DHT12 Communication and synchronization between, by-wire data

format, a transfer 40 Data high first. Specific communicationSequential as shown in the following

figure, communication formats described in the following table.

图 16 Single bus communication timing description

◎Single bus data example:

The name

Single bus format definition

The

starting

signal

Host data bus (SDA) Down over time (18ms), Tells sensors to prepare data