Jump to content
43oh

CC3200 WiFi Channels Limitation Info


Recommended Posts

The CC3200 stopped connecting to an Access Point (AP) after working fine for a while. It transpired that he SSID had been configured for channel 13 which is beyond the CC3200's range (1 to 11) . Some APs can now be configured to look for the channel with least interference so this may prove an intermittent issue if it decides on 12 or 13.

Link to post
Share on other sites

Note that channels 12-14 are not legal for full-power use in North America, so depending on your location the fault may be in the configuration of your AP. (I haven't unboxed my CC3200, but I'd be pretty surprised if it couldn't handle at least channels 12 and 13, but not surprised if its default configuration excludes them.)

Link to post
Share on other sites

I do know there is some API for setting the regulatory compliance country code in the SimpleLink API.

 

See SWRU368 (no version specified), page 136 - http://ti.com/lit/swru368

sl_WlanSet - Enables the user the configure different WLAN related parameters.  The main parameters used are ConfigID and ConfigOpt.  The possible ConfigID and ConfigOpt combinations are:

* SL_WLAN_CFG_GENERAL_PARAM_ID - The different general WLAN parameters are:
 - WLAN_GENERAL_PARAM_OPT_COUNTRY_CODE
 - WLAN_GENERAL_PARAM_OPT_STA_TX_POWER - Sets STA mode Tx power level, a number from 0 to 15, as the dB offset from max power (0 will set maximum power)
 - WLAN_GENERAL_PARAM_OPT_AP_TX_POWER - Sets AP mode Tx power level, a number from 0 to 15, as the dB offset from max power (0 will set maximum power)

There are equivalent config ID's for AP mode and P2P mode for setting country code/regulatory crap.  The argument to this country code is a buffer of two bytes, and I think it is just 2 ASCII characters, e.g. 'U' and 'S' for US.  That's an assumption based on the help text for "WLAN_AP_OPT_CHANNEL" right above it.

 

Likewise, CC31xx Host Documentation - http://software-dl.ti.com/ecs/cc31xx/APIs/public/cc31xx_simplelink/latest/html/index.html - look at the WLAN section, help for sl_WlanSet function.

Link to post
Share on other sites

A list of country codes can be found here: http://www.cisco.com/en/US/products/ps6305/products_configuration_guide_chapter09186a00804ddd8a.html

Not sure if country code can be set after WiFi.begin(...) but you can give it a try. Put this right after your WiFi.begin(..).

uint8_t country[] = "CN"; 
sl_WlanSet(SL_WLAN_CFG_GENERAL_PARAM_ID, WLAN_GENERAL_PARAM_OPT_COUNTRY_CODE, 2, country); 

CN is for China and that regulatory domain allows channel 1-13. Make sure that you replace the country code with the appropriate country code you intend to run the CC3200 LaunchPad.

Link to post
Share on other sites

The CC3200 stopped connecting to an Access Point (AP) after working fine for a while. It transpired that he SSID had been configured for channel 13 which is beyond the CC3200's range (1 to 11) . Some APs can now be configured to look for the channel with least interference so this may prove an intermittent issue if it decides on 12 or 13.

Shouldnt be using 12 or 13 in the UK (not that any body is going to know).

Link to post
Share on other sites

Shouldnt be using 12 or 13 in the UK (not that any body is going to know).

Although sources(1,2) conflict, IEEE Std 802.11-2012 annex D "Regulatory References" and Table E-2 "Operating classes in Europe" strongly suggests that the UK falls under ECC/ETSI/CEPT's regulatory domain and does permit use of channels 1 through 13 in the 2.4 GHz ISM band for Wi-Fi.

 

That may not have been the case at the time of the 2006 reference Cisco cites.

Link to post
Share on other sites

Playing with sl_WlanGet(), looks like it is just a 2-character ASCII pair:

sl_WlanGet(WLAN_GENERAL_PARAM_OPT_COUNTRY_CODE) return value = -2001
ConfigOpt = 9
Return data length = 2
Country code: US

(Not exactly sure why sl_WlanGet returns -2001, as it's supposed to be 0 for success and -1 for error, but obviously it seems to work.)

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...