Chapter 4. Software framework
4.10.37 [Sleep] What aects the average current of ESP32 in modem sleep mode?
The modem sleep mode of ESP32 is achieved by setting wakeup cycles. ESP32 opens RF functions to
communicate during every cycle and closes these functions in the rest of the time.
The average current of this mode is inuenced by several factors, including:
• Wakeup cycle: A shorter wakeup cycle means the chip will be waked up more frequently, which
increases the average current.
• Signal quality: If the Wi-Fi signal is weak, the chip will keep trying to reconnect or send data,
which will increase the average current. Using communication protocols with bigger transmission
power will also increase the average current.
• Hardware conguration: The hardware conguration of the chip also aects power consumption,
such as the number of CPU cores, CPU clock frequency, CPU idle time ratio, power supply voltage,
external crystal oscillator, etc. All of these factors inuence the size of average current.
• Other factors include whether the testing router accurately sends beacon timestamps, whether too
many broadcast packets have been sent, whether peripheral modules are working, etc.
4.10.38 [Sleep] Why the average current measured in modem sleep mode is a bit high?
• A lot of Wi-Fi data sent and received during the test. The more data there is, the less chance there will be for
entering sleeping mode and the higher average current will be.
• The time when the router sends out beacon is not accurate. The station needs to wake up and monitor the
beacon regularly, thus it will wait longer if the beacon time is not accurate. In this way, the station has less
time in sleeping mode and the average current will be high.
• There are peripheral modules working during the test. Please close them before the test.
• The station+SoftAP mode is enabled. During modem sleep state, the current will only be lower in station-only
mode.
4.10.39 [Sleep] Why the average current measured in light sleep mode is a bit high?
Besides for the reasons listed in the last question, the possible reasons also could be:
• The application layer code is running continuously, thus the CPU does not get chance to suspend.
• The application layer has enabled ets timer or esp timer and the timeout interval is short, thus the
CPU does not get chance to suspend.
4.10.40 [Sleep] What kinds of power-saving modes does ESP32 have? What are the dif-
ferences?
There are mainly three modes: minimum modem power-saving, maximum modem power-saving, and
no power save modes.
• Minimum modem: default type. In this mode, the station wakes up to receive beacon every DTIM
period, which is equal to (DTIM * 102.4) ms. For example, if the DTIM of the router is 1, the
station will wake up every 100 ms.
• Maximum modem: in this mode, the interval to receive beacons is determined by the lis-
ten_interval parameter in wifi_sta_config_t. The interval is equal to (listen interval
* 102.4) ms. For example, if the DTIM of the router is 1, and the listen interval is 10, the station
will wake up every 1 s.
• No power save: no power save.
Espressif Systems 134
Submit Document Feedback
Release master
To Next Page
Loading...