User's Manual

USER MANUAL PREVIEW

PTM 535BZ – BLUETOOTH AND ZIGBEE GREEN POWER PUSHBUTTON TRANSMITTER

3.3 Telegram format

PTM 535BZ transmits Bluetooth Low Energy (BLE) radio telegrams in the 2.4 GHz band. This

chapter provides a summary of the BLE frame structure; for detailed information please refer

to [2]. Figure 7 below summarizes the high-level BLE frame structure. The content of these

fields is described in more detail below.

Figure 7 – BLE frame structure

3.3.1 Byte order

BLE uses little endian location meaning that if a data structure (e.g. Access Address, Header

or Source Address) is bigger than one byte then the least significant byte is transmitted first.

Considering for instance the case of the four-byte Access Address 0x8E89BED6, these 4 bytes

will be transmitted (and received) in the order 0xD6 first, 0xBE second, 0x89 third and 0x8E

last.

3.3.2 Preamble

The BLE Preamble is 1 byte long and identifies the start of the BLE frame. The value of the

BLE Preamble is always set to 0xAA.

3.3.3 Access Address

The four-byte BLE Access Address identifies the radio telegram type. For advertising frames,

the value of the Access Address is always set to 0x8E89BED6.

3.3.4 Advertising PDU Header

The Advertising PDU Header identifies certain radio telegram parameters. Figure 8 below

shows the structure of the Advertising PDU header. The Advertising PDU Header is set to

0x1342 for data telegrams and 0x2442 for commissioning telegrams.

Figure 8 – Advertising PDU header structure