CC3220SF: softAP channel settings

Hi,

I think safe option is set country code to US and channel for AP mode between 1 and 11. But generally this question is for certification laboratory.

Jan

Hi,

By definition, EU would use channels 1-13 and US 1-11 so if you want a product to work in both regions, you need to pick the common ground which is 1-11. You also have an API to set the backoff from maximum power.

Regards,

Shlomi

Hi Shlomi, Hi Jan,

Thank you for the feedback. Is there a recommended value to set the backoff from maximum power ?

Also if the channels are set to 1-11. will the connection fail in EU market where some APs operate on channel 12-13 ?

Hi,

we have the API to "play" with the AP power but eventually you need to pass radio certification so you would need to set the relevant country code (there is an API for this as well). The country code dictates the channel mask. So if you choose 1-11 then yes, you would not be able to connect on 12-13 but this is if you want to have a "unified" configuration to all regions.

Shlomi

Dear Shlomi,

1. Do you know if there will be any APs that will force to operate only on channels 12 and 13 ?

2. But if we set country code to US - the max Tx power for EU is 20dBm (100 mW) but for US is 30dBm (1 Watt). If the country code is set to US, the Tx power limits for EU will not be fulfilled. Do you suggest to set the offset from the max Tx power using the API  sl_WlanSet(SL_WLAN_CFG_GENERAL_PARAM_ID, SL_WLAN_GENERAL_PARAM_OPT_STA_TX_POWER, 1, (uint8_t *)&u8TxPower) and set the offset value in a way that max Tx power is 100mW ?

Thank you in advance.

Hi,

Just wanted to emphasize here the regulatory aspect. You are right that TX power is different between the two zones in addition to the channel list. It gets even more complicated with 5GHz (although this one is CC3220 so only 2.4GHz is considered). As of now, TI is recommending to set the country code via a dedicated API (or via Uniflash) which makes the device match the country it is designed for. This way, all the internal regulatory tables are used accordingly. Please note that even if we get to a way to set 'EU' and use some APIs to limit channels and power, working in AP role would still generate the country element IE in beacon as 'EU' which is bad. So currently I do not see a way to simply set a unified country code that matches all regions but I can take it offline internally to duscuss.

Regards,

Shlomi

Hi Shlomi,

An update here from a certification lab - maybe it helps others too

Setting country code as US (Channels - 1 to 11), and max Tx power as 100mW, the device can be globally used in different markets. Info in the beacon seems to not be a regulatory requirement.

What offset for Tx power should be set in the API (sl_WlanSet(SL_WLAN_CFG_GENERAL_PARAM_ID, SL_WLAN_GENERAL_PARAM_OPT_STA_TX_POWER, 1, (uint8_t *)&u8TxPower))to achieve a max tx power of 100mW ?

Thanks in advance!

Hi,

The reason they say it is because US is the most restrictive in terms of power and channels. Basically, the TX_POWER is relative to the maximum power in 1dB resolution. "The value is from 0 to 15, as dB offset from maximum power (0 is MAX power)". So it needs to be tested on your board to make sure what is the aggregated output power and make sure that reducing is indeed in 1dB resolution.

100mW is equivalent to 20dBm so I expect that it would be reduced in 1dB each step.

Didn't you mention AP role (here you mentioned SL_WLAN_GENERAL_PARAM_OPT_STA_TX_POWER)?

Shlomi

Hi Shlomi,

Understood the power offset setting.

I would like to have the setting for both AP mode and STA mode. Is a different configuration in the API required for AP mode?

it is similar but there are two different opcodes for STA and AP as you noticed.

SL_WLAN_GENERAL_PARAM_OPT_STA_TX_POWER and SL_WLAN_GENERAL_PARAM_OPT_AP_TX_POWER