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Figure 16: sending a read command example temperature and humidity

Steps three : To return the data read or confirmation signal

Send read / write command, the host is required to wait at least 1.5ms, and then sends a read

timing, reads return data example shown in Figure 17; must be noted that, when you read the data,

issued after the completion of I

C address, wait at least 30μs and then sent over the next serial clock,

reading data, or communication error occurs.

Figure 17: Read the sample temperature and humidity values

Host read back the data as follows:

0x03(Function Code)+0x04(data length)+0x03(high humidity)+0x39(low

humidity) +

0x01 (high temperature) +0x15(low temperature)+0xE1(CRC checksum low

byte) + 0xFE

(CRC checksum high byte);

Therefore: 0339H = 3×256 +3×16 +9 = 825 => humidity = 825÷10 = 82.5%

RH;

0115H = 1×256 +1×16 +5 = 277 => temperature = 277÷10 = 27.7 ℃

These three steps can be completed by the sensor reads all registers, a write operation (the user

can write registers, only five, namely the status register, register four users, while the status register

can only be written separately, otherwise it will error) ; the user in the design, follow these three

steps must be fully read and write.

After sending the sensor data, trigger a temperature and humidity measurements; After the

measurement is completed, the recording temperature and humidity values, then completed a

communication, the sensor automatically goes to sleep; therefore, as long unread sensors

continuously read the second sensor, in the second reading of the temperature and humidity back to

the latest value (minimum interval of continuous reading 2S).

8.2.5 Peripheral read flowchart

AM2321 read I

code reads C51, need to download the client, please visit our website (www.aosong.com) associated

download, this manual does not provide code instructions.

2

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Enterprise QQ: 4006305378

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