ESP8266 Developer Zone The Official ESP8266 Forum 2017-02-28T19:26:16+08:00 https://bbs.espressif.com:443/feed.php?f=7&t=3385 2017-02-28T19:26:16+08:00 2017-02-28T19:26:16+08:00 https://bbs.espressif.com:443/viewtopic.php?t=3385&p=11388#p11388 <![CDATA[DTIM period setting]]> In AP i can set the beacon_interval, but i cannot set the DTIM directly.
And i see,after sniffing packets on air, that my AP decides the appropriate DTIM by its own.
Not good, because it controls the wake up from from light sleep of a connected client to let the client respond to the beacon.

And due to the unknown processes of the proprietary stack my light sleep entering is very unstable if i need to repeat it.
I need to let my application in idle state for a lot of milliseconds after some spi ping pongs and subsequent tcp tx/rx to be sure espressif enters the light sleep in a predictable manner ( no timers disturbing ).

The picture below display on an espressif used as client:
- current consumption ( yellow )
- spi ping pong ( violet and blue ) , when it ends it means that even tcp tx/rx is completed.

Beacon interval is set to 200 ms, and i can see it with Wireshark.
DTIM period is 2, i.e client has to wake up every 2 beacons, check the single spike that occurs every 400ms.
The module is inside a board but i think i can relate the other yellow spikes, when esp is on, to the activities of the AP dealing with other beacon/probes requests..wierd reflection on the client isn't it?
Note the extra time time where espressif is on before entering light sleep, i need to allow this delay eitherway no light sleep at all.

tek00002.png

Statistics: Posted by Mdb — Tue Feb 28, 2017 7:26 pm


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