<p>DHT11 uses the single bus protocol to communicate with the single chip microcomputer. After the single chip microcomputer sends a reset signal, DHT11 switches from the low-power mode to the high-speed mode. After waiting for the end of the host reset, DHT11 sends a response signal and pulls up the bus to prepare for data transmission. The complete data is 40 bits at a time, and is transmitted in the order of high bits first and low bits last. <br>
The data format is: 8 bit humidity integer data + 8 bit humidity decimal data + 8 bit temperature integer data + 8 bit temperature decimal data + 8 bit checksum, a total of 5 bytes (40 bits) of data. Since the DHT11 resolution can only be accurate to the ones place???, the fractional part of the data is all 0. The checksum is the sum of the first four bytes of data. The purpose of the checksum is to ensure the accuracy of data transmission. <br>
The data format is: 8 bit humidity integer data + 8 bit humidity decimal data + 8 bit temperature integer data + 8 bit temperature decimal data + 8 bit checksum, a total of 5 bytes (40 bits) of data. Since the DHT11 resolution can only be accurate to the ones place, the fractional part of the data is all 0. The checksum is the sum of the first four bytes of data. The purpose of the checksum is to ensure the accuracy of data transmission. <br>
The DHT11 triggers temperature and humidity collection only after receiving the start signal. If the host does not send a reset signal, the DHT11 willnot take the initiative to collect temperature and humidity. When the data collection is complete and there is no start signal, the DHT11 automatically switches to the low speed mode. <br>
Note: Because DHT11 timing requirements are very strict, in order to prevent interruptions from interfering with the bus timing when operating the timing, the total interrupt is turned off first, and then turned on only after the operation is complete. <br>
