Can ESP32 receive GFSK, or other keying like OOK, etc...

[dapeake]

Hello all,

Is it possible to disable the BT and Wi/Fi stacks and use the ESP32’s 2.4ghz radio hardware to receive and decode a (simplex) keying scheme such as GFSK?

Thank you!

Dan
San Jose, CA

[ESP_Sprite]

To my knowledge, not in any way that is publicly documented.

[dapeake]

Thanks for the comment. Anyone have any contact advice on how to reach out to Espressif to see if they can provide insight?

Thanks,

Dan

[ESP_Sprite]

You can try poking sales@espressif.com. I'll be honest with you, though: since you're more or less asking for either something that the hardware can't do, or doing something that means implementing an API deep in the PHY layer, I'm not giving you much chance there.

[dapeake]

I agree. I will try, just to tick that box. But I am not optimistic, Espressif and chip makers in general, need to let the community handle this kind of support. Reminds me of the Airforce transport jet last week in Kabul surrounded by thousands - if you're too nice the plane won't fly.

I read about an FCC compliance testing firm getting the client to modulate the radio with the BT stack disabled.. but the conversation ended there. Another possibility/clue is there is radio calibration API/library stored in NVM. That sounds like hardware level control of the radio.

Will post back if I find something. The ability to read ISM simple keying, is a great feature that Espressif should add to is software development / API library (they may have thought of it, but it could have presented a regulatory / market can of worms.) Without ISM simple keying, I must add an external radio ( and possibly jump through more regulatory hoops to get my invention FCC approved).

[dapeake]

Future ESP32 community searchers: I found a fascinating study related to this subject that helps answer some of my questions (published in this year 2021/April).

While not specific to ESP32 it possibly addresses the thing am asking for, which I have learned is called back-channeling, which is emphasized in the study because it results in an order of magnitude power savings on the Rx side for asynchronous event tracking/messaging (I do not require RX-side power savings, but the power saving scheme does things I need). My (possibly flawed) understanding is Backchanneled ("BLE Wu/Rx") departs from BLE compliance to bypass the BLE baseband controller / PLL Synthesizer and constantly listen for simple, low frequency, low symbol rate, FSK, OOK identified advertisements, which when heard wakes the sleeping (giant) BLE stack to do its high speed work. The author sites a number of parties who have successfully carried out experiments, I have not followed up on the citations, however most are academic.

Search for: "Bluetooth Communication Leveraging Ultra-Low Power Radio Design, Omar Abdelatty

Dan