ESP8266 Community Forum

schufti wrote:You may be able to read out flash (same tool you flash it with) and search for sdk string, but what for?

I will tell you why


I have several different ESP8266 modules/boards,
from different manufacturers, and they came with different SDK and AT versions.


Now see this interesting phenomenon:
When I do AT+CWLAP, to list all the visible WLANs in my area,
then on one module I get a list of 2-3 networks
and on a different module (actually board, the Uno+Wifi board in the picture above, in my previous post),
I get a list about 20 WLAN networks.

And the 20 list is the one that should be,
because when I use a laptopthat has Wifi, or a tablet with Wifi, or any other non-ESP device with Wifi,
I see about 20 networks here.. (I live in an apartment building..)..


So,
the fact that one module/board succeeds in seeing only 2-3 networks,
and another module/boards can see 20 networks,
makes me think about 2 possible reasons for it: Hardware, or Software.


Let's start with Hardware:
A module/board's Hardware can be better, for example, by having a better antenna,
or a better power management, that provides a cleaner DC to the ES8266 module.
(there might be more things, I gave 2 for example)


Now regarding Software:
One version of the SDK+AT might be better than another version of it.
Sometimes, it's not necessarily that the newer version is better,
you can sometimes see that an older version, that might have less features, had better radio capabilities.

BTW this may not necessarily be in code.. It can be RF Parameters that were better set
(or were better for your WLAN) than the parameters in the newer version of the Firmware..


So you see,
due to the fact that the Uno+Wifi board shows much better RF abilities,
(at least when I look at how it scans the WLANs), it makes me really curious to know what version of SDK it is running.


I should mention that I haven't necessarily isolated the reason for its superiority to be Software/Parameters,
it might be the Hardware too.

To know that, there is a very simple way to check:
I will Flash the Uno+Wifi with the same version of Firmware that I flashed the other module that I have,
and see the result of AT+CWLAP..

If the Uno+Wifi still displays 20 networks, when it has the same Firmware version like the other module,
yet the other module, with the same version, displays only 3,
the it's mostlikely is a Hardware issue and not software..


I am really curious about it, because naturally our tendency is to get the most out of the module/board,
and get the best possible reception..
Also you learn quite much on the way

there should be an AT command to read the version of AT fw on both modules.
Somehwere on their servers Espressif holds all official sdk versions (contain also AT fw).
So maybe you can get to required info much easier ...