Datasheet

- 22 -
Humidity:0000 0010 1001 0010 = 0292H (hex) = 2
×
256 + 9
×
6 + 2 = 658 => Humidity =
65.8% RH
Temperature:0000 0001 0000 1101 = 10DH (hex) = 1
×
256 + 0
×
16 + 13 = 269
=> Temperature = 26.9
℃
◎
Special Instructions:
When the temperature is below 0
℃
temperature data for a top position.
Example One: -10.1
℃
expressed as 1,000,000,001,100,101
Temperature: 0000 0000 0110 0101 = 0065H (hex) = 6
×
16 +5 = 101
=> Temperature = -10.1
℃
Example Two: The received data 40:
0000 0010 1001 0010 0000 0001 0000 1101 1011 0010
High humidity 8 Low humidity 8 High temperature 8 Low temperature8 Parity bit
Calculated as follows:
0000 0010+1001 0010 +0000 0001+0000 1101=1010 0010
≠
1011 0010 (Parity error)
The received data is not correct, give up, again receiving data.
8.3.3 Single-bus communication timing
Hosts (MCU) sends a start signal (data bus SDA low for at least 800
μ
s) After, AM2320
transition from sleep mode to high-speed mode. After completion, the master start signal, AM2320
transmit a response signal, the data sent from the data bus 40Bit SDA serial high byte is transmitted
first; data is sequentially transmitted high humidity, low humidity, high temperature, low temperature,
the parity bit , sent a message to trigger the end of data collection, collecting sensor automatically
transferred to the end of the sleep mode until the next traffic coming
Detailed timing signal characteristics are shown in Table 10, a single bus communication
timing diagram shown in Figure 21.
Figure 21: AM2320 single bus communication timing
Note: The temperature and humidity data from the AM2320 host always read the previous measurement, the
measurement interval twice as long, please read twice in a row is the second time in the real-time temperature and
humidity values, while two read take a minimum interval 2S.
Table 10 : single bus signal characteristics
Symbol
Parameter
min
typ
max
unit
T be
Host starting signal low time
0.8
1
20
ms
T go
Host Bus release time
20
30
200
µ S
T rel
Response time low
75
80
85
µ S
T reh
Response time high
75
80
85
µ S
T low
Signal "0", "1" low time
48
50
55
µ S