RE: Unclear BLE channel map definition

Arno — Thu, 14 Sep 2023 07:46:38 GMT

Thx, that perfectly makes sense ;-)

RE: Unclear BLE channel map definition

Kenneth — Wed, 13 Sep 2023 20:19:29 GMT

Hello,

You are mixing Wifi channels with BLE channels, you are right that for Wifi (that have much higher bandwith of 20/40MHz that only 11 channels are allowed), but for BLE that have a bandwidth of 1-2MHz you can fit all 39 channels legally within all radio regulations in the world.

[quote user=""]

The default channel map where all channels are used seems to be:

uint8_t chan_map_all_channels_active[5] = { 0xff, 0xff, 0xff, 0xff, 0x1f };

[/quote]

This channel map control the 37 channels that are used when a link is established, since [5]bytes are 40bit, the top 3bits are 0 for the fifth byte of the channel map (thereby it's 0x1f). For advertisment all 3 channels are used.

Honestly speaking there is no need for you to change this, use all channels is overall the safest bet (unless you are a making a phone and have an internal WiFi chipset and thereby may want to avoid some of the channels). This is illustrated with the yellow (Wifi) vs. the blue (BLE) in the figure. The dark green in the figure is advertisment channels.

Likely I didn't answer all your questions here, but hopefully the above make sense.

Kenneth