SPWF00xx Poor Wi-FI Peformance - Switching Between AT Data and Command Modes

[Jon Lamborn]

Posted on January 30, 2017 at 23:57

We are trying to reach real-time 50mS per round trip of 20 byte TCP messages of receive and then send response. I'm actually seeing closer to 150mS round trip time. Much of this time is taken up in switching between data and command mode. Our measurements indicated 88mS or 44mS per side. Switching to command mode requires the following characters Tx:'at+s' and Rx:'+WIND:59:Back to Command Mode'. At 115,200 bps that's 0.00295sec at 10 bits per char which is 6.8% of 44mS delay. What is the other 93.2% of the delay time? How long should it take to switch from data mode to command mode? This appears to be putting excessive overhead on our message traffic?

[Gerardo GALLUCCI]

Posted on February 04, 2017 at 11:46

I can perform some test on SPWF01S module (without X-CUBE-WIFI1).

We already know how much time is required to switch back from data to command mode. Do you want to cross this information with some TCP traffic? What's the RTT? What's your scenario?

1 - SOCKD open

2 - incoming client, and automatic switch to data mode

3 - escape sequence to switch back to command mode --> measure done

4 - receive something (WIND pending)

5 - ...