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Senior
March 24, 2022
Solved

SUBGHZ _ Configure data reception _ little-endian

  • March 24, 2022
  • 2 replies
  • 757 views

Hello,

I configure SUBGHZ peripheral to communicate with a RF433MHz module.

The RF433MHz module send preamble and synchronisation word in little-endian fashion (bit 0 first, bit 7 last)

For example, a Sync Word pattern of 0x2D 0xD4 is transmit as  0xB4 0x2B and the preamble of 0b10101010 is received 0b01010101

How can I configure the SUBGHZ peripheral to receive preamble and synchronization word correctly?

Thank you,

Sincerely.

This topic has been closed for replies.
Best answer by malarab

It is ok, I have resolved the problem of the preamble, the preamble have 8 bytes length but I should configure 8-bit preamble detection to detect it correctly.

For the synchronisation word I receive it always in little-endian: if my transmitter sends 0x2D 0xD4, I should configure 0xB4 0x2B for SUBGHZ peripheral!

Consequently, I receive data correctly :smiling_face_with_smiling_eyes:

2 replies

malarabAuthor
Senior
March 24, 2022

Here more precision:

If I send:

Preamble: 1010 1010

Sync word: 0010 1011 (0x2D)

Data: 0111 0101 (0x75)

Bits on air will be: 0101 0101 0100 1101 1110 1010

Because SUBGHZ interface is waiting to 1010… the first bit (the 0) is ignored and I receive:

1010 1010 1001 1011 1101 010 (so the packet will be shifted to left)

So:

received preamble: 1010 1010

received Sync word: 1001 1011 (wrong)

data will be also wrong but just because the shifting. 

malarabAuthorBest answer
Senior
March 24, 2022

It is ok, I have resolved the problem of the preamble, the preamble have 8 bytes length but I should configure 8-bit preamble detection to detect it correctly.

For the synchronisation word I receive it always in little-endian: if my transmitter sends 0x2D 0xD4, I should configure 0xB4 0x2B for SUBGHZ peripheral!

Consequently, I receive data correctly :smiling_face_with_smiling_eyes: