Wifi on Broadcom IC built into TX2 SOM


We want to use the broadcom ic built into the tx2 as an AP using the full 5ghz 802.11a band. The interface currently limits to only channel 44. According to the certification documents it looks like all channels are supported in AP mode. Is there a way to enable other channels?


It depends on what is your application which setup AP. Are you using NetworkManager or hostapd?

This thread has some example.

Hello WayneWWW
In your response to the thread linked:

It is mentioned support exists for Channel 149 (U-NII-3 band), however this doesn’t show support on the SOM we have (only shows Channels 36-48, 52-64). Also, we cannot change the channel in AP mode as it always defaults to 44 in 11ac mode.

The Regulatory and Compliance documents for TX2 show complete support include DFS/TPC for the 5.5-5.7GHz band channels.

How do we enable the channels in U-NII-2C band (Channels 100-144, 5.5-5.7GHz) in AP mode, 802.11n and/or 802.11ac?


WayneWWW, to answer the earlier question, we use hostapd.

The channels which our chip/fw can support are listed by using “iw list”. In general, if your channel in hostapd.conf is invalid, ap mode should crash.

As a result, when you say “Also, we cannot change the channel in AP mode as it always defaults to 44 in 11ac mode.”, did you mean none of your channel works?

The channels ‘supported’ via ‘iwlist’:
Channel 36 : 5.18 GHz
Channel 40 : 5.2 GHz
Channel 44 : 5.22 GHz
Channel 48 : 5.24 GHz
Channel 52 : 5.26 GHz
Channel 56 : 5.28 GHz
Channel 60 : 5.3 GHz
Channel 64 : 5.32 GHz

However, I can only set channels 36-48 using hostadp value. Any channel from 56-64 do not bring the interface up to be seen by a client. However there are no noticeable errors visible in logs (other than txpower setting error), and it appears to be up via ‘iwconfig’.

The AP is always brought up in AC/N mode even though AC mode is not added into our hostapd file.

Channels 36-48 are indoor only channels, and cannot be used outside in AP mode so we are stuck without a proper solution.


Just checked the wirelsess compliance document. These channels are DFS-p, which means our chip support these channels in passive mode(station mode). Tegra can only access such channels enabled by other APs.


Where can we find which channels are supported in AP mode (in the 5GHz band)?


Please refer to wireless compliance guide.

Thanks Wayne. So based on this and Craigs’s comments that channels 36-48 are indoor wifi channels, it sounds like the TX2’s wifi module doesn’t support outdoor frequencies in AP mode. Can you confirm this?

Hi Jerry,

Unfortunately, yes, you can say that we don’t support those outdoor channels in AP mode.