Wifi will enter standby mode when there is no data transmission. There are two situations in this situation:
1. If there is no AP connection, the wifi chip will enter deep sleep. At this moment, it is completely controlled by the master control, and the power consumption is shown as uA level on wifi power consumption meter.
2. When the AP is connected, the wifi chip will enter the sleep mode, but it will automatically get up to check the data. The wake-up period depends on the DTIM interval of the router AP (this value depends on the AP's ability to cache data). The value of DTIM interval is the interval of n Beacon, which is set to 1 by default. At this point DTIM interval is equal to beacon interval. Generaly speaking, when DTIM is equal to 1, the average current is 1mA. Of course, this value means that in the case of no data transmission and reception, wifi chip continues to sleep when waking up at regular intervals. This is also the most important low power consumption indicator for wifi chip manufacturers.
3．After DTIM value is set, TSF Timer (timer synchronization function) will be configured inside Wifi chip. This timer's interval is equal to DTIM's interval. It will wake up the wifi chip regularly to receive Beacon. Because Beacon has a flag about whether it has its own data cache. If any data is found, keep AP awake and send PS-poll packets to it so that it can send all cache packets. At the same time, it needs to wake up Host to process the packets. If it is found that Beacon has no cache information about itself, it will continue to sleep until the next DTIM period arrives and repeat this operation.