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FORUM

LLCC68 address filtering

Semtech Transceivers SX126x family
#1

Hi,
We’ve been playing around with the LLCC68 to port our FSK-based radio stack to it.
We’re starting to send/receive messages but datasheet is a difficult to understand regarding address filtering.

  1. Datasheet says “Node or Broadcast address are […] added automatically in hardware”. How is the device supposed to know which destination node I wand to speak to ? I the 0x06CD “Node Address” register my own address or the destination one ?

  2. When I receive a packet, the matched address is automatically removed before handing the payload in Buffer. How can I known if it was a “own address” match or a “broadcast” match ?

Best regards,
RB

#2

Hello @bouffondu95,

When sending a packet, the address automatically added to the packet in the one configured in “Node address” register (0x06CD).

When receiving a packet, it is not possible to know which address matched so far. I will ask the designer if there is a register where this data is stored.

#3

Hi Mantoine,

Thank you for this quick answer.
I’ve managed to understand the address/length added automatically to the frame.

Hoewever, I’d be very interested if a register holds the matched address.

More information on our use case below :

Our use case is actual address stored on more than 1 byte.
So far on other radio (SX1231 for example), I used to filter on the LSB and doing the rest on host.
For example, if node is 0x1234, the radio filters “most” of the unwanted message by filtering on address 0x34 (and 0xFF for 0xFFFF broadcast address) and the host then check the full address.

On LLCC68, as we don’t know the address that matches, we don’t know if the packet match was 0x34 or 0xFF. Thus we might mix addresses like 0x1234, 0x12FF, 0xFF34 and 0xFFFF.

#4

Hi @mantoine,
Any news from the designers on the possibility to access the match address through some register ?

#5

Hi @bouffondu95,

Yes, I got an answer: there is no register you can read to know the type of address that matched.