Pic4: AM2302 Typical circuits for single bus
7.2、Single-bus communication protocol
◎Single bus Description
AM2302 device uses a simplified single-bus communication. Single bus that only one data line, data
exchange system, controlled by the data line to complete. Equipment (microprocessor) through an
open-drain or tri-state port connected to the data line to allow the device does not send data to release the
bus, while other devices use the bus; single bus usually require an external about 5.1kΩ pull-up resistor, so
when the bus is idle, its status is high. Because they are the master-slave structure, only the host calls the
sensor, the sensor will answer, so the hosts to access the sensor must strictly follow the sequence of single bus,
if there is a sequence of confusion, the sensor will not respond to the host.
◎Single bus to send data definition
SDA For communication and synchronization between the microprocessor and the AM2302, single-bus
data format, a transmission of 40 data, the high first-out. Specific communication timing shown in Figure 5,
the communication format is depicted in Table 5.
Pic5: AM2302 Single-bus communication protocol
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