DocID022544 Rev 3

7/23

AN4018

Framing

3

Framing

The communication modulation is an X-PSK, and the physical frame is the typical PSK

frame, shown in Figure 3.

Figure 3. PSK frame

where:

•

Preamble length: 32 bits

•

Unique word: 16 bits

•

Mode: 8 bits

•

P_SDU length: 8 bits

•

P_SDU: max. 255 bytes

The P_SDU contains the data link frame which has the structure shown in Figure 4.

Figure 4. Data link frame

where:

•

“Type” defines the type of frame, which can be:

–AllowJoin

–

JoinReq

–JoinAck