What is the purpose of SUBGHZ registers 0x8E2 and 0x8E5 in the STM32WLE5

[Strooom]

While reverse engineering a demo application from ST / Seeed ( Seeed-Studio/LoRaWan-E5-Node at qian (github.com)), I started monitoring all commands and register access from the MCU to the embedded SX126.

I see there are writes to register:

WR [08E2]:0C

WR [08E5]:20

Those registers are not mentioned in the datasheet from Semtech, nor the STM32WLE5 datasheet from ST…

What is the purpose of those registers ?

Why is the SW writing those values ?

Why is this not in the datasheet ???

[Strooom]

Got an answer from Semtech forum :

The registers you mentioned are used in sx126x_get_random_numbers function.

They are altered to modify some internal logic allowing random numbers to be generated from RF noise without being impacted by a potential jammer.

[Tesla DeLorean]

/*! * The address of the register used to disable the LNA */

#define SX126X_REG_ANA_LNA 0x08E2

/*! * The address of the register used to disable the mixer */

#define SX126X_REG_ANA_MIXER 0x08E5

Clearing bits 0 and 7 respectively.

Did they point to any register level documentation?

[Strooom]

Not yet : here is a link to the topic on Semtech forum : What does SX126 register 0x8E2 and 0x8E5 do? - Semtech Transceivers - FORUM