User's Manual

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PTM 535BZ – BLUETOOTH AND ZIGBEE GREEN POWER PUSHBUTTON TRANSMITTER

4.3 Telegram format

PTM 535BZ transmits ZGP radio telegrams in the 2.4 GHz band according to the Zigbee Green

Power specification [3] which uses IEEE 802.15.4 [5] as lower layer standard. Please refer to

these specifications for detailed, up to date information.

Figure 22 below summarizes the high-level IEEE 802.15.4 / Zigbee Green Power frame struc-

ture. The content of these fields is described in more detail in the next chapters.

Figure 22 – IEEE 802.15.4 / Zigbee Green Power frame structure

4.3.1 Data integrity

Correct reception of the IEEE 802.15.4 frame is ensured using a 2 byte Cyclic Redundancy

Check (CRC16) which forms the IEEE 802.15.4 MAC Trailer field.

4.3.2 Byte order

ZGP uses little endian byte order meaning that if a data structure (e.g. Source Address,

Frame Control or Sequence Number) is bigger than 1 byte then the least significant byte is

transmitted first. Considering the case of the 4 byte Source Address 0x01501234, these 4

bytes will be transmitted (and received) in the order 0x34 first, 0x12 second, 0x50 third and

0x01 last.

4.3.3 IEEE 802.15.4 PHY Header

The IEEE 802.15.4 PHY header consists of the following fields:

 Preamble (4 byte long, always 0x0000:0000)

 Start of Frame (1 byte long, always 0xA7)

 Length of Frame (1 byte long, length depending on ZGP payload length)

The structure of the IEEE 802.15.4 PHY header is shown in Figure 23 below.

Figure 23 – IEEE 802.15.4 PHY header structure