ESP32-S3 | PCB Design | Disable Radios?

esprelearn
Posts: 1
Joined: Fri May 09, 2025 7:13 pm

ESP32-S3 | PCB Design | Disable Radios?

Postby esprelearn » Fri May 09, 2025 7:24 pm

Hi,

Is it possibly mentioned in the documents somewhere about how to completely disable the radios on ESP32-S3?

A resistor or other component somewhere? A voltage rail/power domain?

Failing this is there something else that would essentially achieve the same such as attenuation of transmit/receive?

(High platform security application where the radios are not allowed.)

Thanks folks

mikemoy
Posts: 690
Joined: Fri Jan 12, 2018 9:10 pm

Re: ESP32-S3 | PCB Design | Disable Radios?

Postby mikemoy » Mon May 19, 2025 6:58 pm

They are disabled by default. You have to intentionally turn them on in software.

MicroController
Posts: 2672
Joined: Mon Oct 17, 2022 7:38 pm
Location: Europe, Germany

Re: ESP32-S3 | PCB Design | Disable Radios?

Postby MicroController » Mon May 19, 2025 10:09 pm

Would be fun to sell that to a client...
"Huh? - Oh that part. That's just the antenna. You know, normally used to send radio signals." - "Interesting question. I mean, yeah, technically it could be used to wirelessly leak sensitive data, but we're not doing that. Let's just ignore it's there, ok?" ;-)

I doubt there's a defined way to permanently/physically disable the RF part of the ESP chips. At least I haven't seen any hint in any documentation on the possibility of that, specifically there's no special power supply pin or the like. I guess the best bet would indeed be shorting the RF output to GND via a resistor, as an additional mitigation layer against potential malicious code trying to use the radios for communication if nothing else.

Maybe there is some undocumented way to effectively cripple the RF part via some eFuses or something? But maybe/probably not.

(Alternatively just buy an ESP32-C3 "Super Mini" board - they often come with crippled RF performance from the factory ;-))

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