CH 37
CH 38
CH 39
INTERVAL
(20ms or 10ms )
CH 37
CH 38
CH 39
INTERVAL
(20ms or 10ms )
CH 37
CH 38
CH 39
Figure 5 – Default radio transmission sequence
3.3 User-defined radio transmission sequences
In certain situations, it might be desirable to transmit radio telegrams on channels other than the three
advertising channels.
SR-SBP2801-BLE-E therefore allows to select the radio channels to be used for the transmission of data
telegrams and commissioning telegrams. The following transmission modes are supported:
1.Both commissioning telegrams and data telegrams are transmitted on the advertising channels as three
advertising events. This is the default configuration and described in chapter 3.2 above.
2.Commissioning telegrams are transmitted on the advertising channels as three advertising events while data
telegrams are transmitted in a user-defined sequence as described below.
3.Both commissioning and data telegrams are transmitted in a user-defined sequence as described below.
The selection of the transmission mode is done using the VARIANT register of the NFC configuration interface
as described in chapter 6.7.9.
3.3.1 Supported radio transmission sequences
SR-SBP2801-BLE-E supports the following user-defined sequences:
1.Three channel sequence
This sequence is similar to the default Advertising Event with the difference that the user can select the radio
channels to be used. The three-channel sequence is described in chapter 3.3.2 below.
2.Two channel sequence
In this sequence the radio telegram is transmitted using four transmissions on two radio channels. It is
described in chapter 3.3.3 below.
3.One channel sequence
In this sequence the radio telegram is transmitted using six transmissions on one radio channel. It is described
in chapter 3.3.4 below.
The selection of user-defined radio transmission sequences is made via the VARIANT register of the NFC
configuration interface, please see chapter 6.7.9.
3.3.2 Three-channel radio transmission sequence
The three-channel radio transmission sequence is similar to the default transmission sequence. The difference
is that the radio channels (BLE Channel 37, 38 and 39 in the default transmission sequence) can be selected
using the registers TX_CHANNEL1, TX_CHANNEL2 and TX_CHANNEL3.
The SR-SBP2801-BLE-E telegram will in this mode be transmitted on the radio channel selected by
TX_CHANNEL1 first, immediately followed by a transmission on the radio channel selected by TX_CHANNEL2
and a transmission on the radio channel selected by TX_CHANNEL3.
This transmission sequence will be sent three times in total as shown in Figure 6 below.
The default interval between the advertising events is 20 ms. Starting with product version DC-06 it is possible
to reduce this interval to 10 ms via the NFC configuration interface. See chapter 6.7.9 for details.
TX_CHANNEL1 TX_CHANNEL2 TX_CHANNEL3
INTERVAL
(20ms or 10ms )
TX_CHANNEL1 TX_CHANNEL2 TX_CHANNEL3
TX_CHANNEL1 TX_CHANNEL2 TX_CHANNEL3
INTERVAL
(20ms or 10ms )
Figure 6 – Three channel radio transmission sequence
The format of TX_CHANNEL1, TX_CHANNEL2 and TX_CHANNEL3 is described in chapter 6.7.10.
3.3.3 Two-channel radio transmission sequence
The two-channel radio transmission sequence removes transmission on the third radio channel (selected by
TX_CHANNEL3) and instead repeats the transmission once more (four times in total).
The SR-SBP2801-BLE-E telegram will in this mode be transmitted on the radio channel selected by
TX_CHANNEL1 first, immediately followed by a transmission on the radio channel selected by
TX_CHANNEL2.
This two-channel transmission sequence will be sent four times in total as shown in Figure 7 below.
The default interval between the advertising events is 20 ms. Starting with product version DC-06 it is possible
to reduce this interval to 10 ms via the NFC configuration interface. See chapter 6.7.9 for details.
Figure 7 – Two channel radio transmission sequence
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL1
Figure 8 – Single channel radio transmission sequence
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL2
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL2
TX_CHANNEL1
INTERVAL
(20ms or 10ms )
TX_CHANNEL2
TX_CHANNEL1 TX_CHANNEL2
3.3.4 Single-channel radio transmission sequence
The single-channel radio transmission sequence removes transmission on the second and third radio channel
(selected by TX_CHANNEL2 and TX_CHANNEL3 respectively), i.e. all transmissions will be on the radio
channel selected by TX_CHANNEL1.
The SR-SBP2801-BLE-E telegram will be sent six times on this radio channel as shown in Figure 8 below.
The default interval between the advertising events is 20 ms. Starting with product version DC-06 it is possible
to reduce this interval to 10 ms via the NFC configuration interface. See chapter 6.7.9 for details.
The format of TX_CHANNEL1 is described in chapter 6.7.10.
4. Telegram format
SR-SBP2801-BLE-E transmits Bluetooth Low Energy (BLE) radio telegrams in the 2.4 GHz band. For detailed
information about the Bluetooth Low Energy standard, please refer to the applicable specifications.
Figure 9 below summarizes the BLE frame structure.
Figure 9 – BLE frame structure
The content of these fields is described in more detail below.
The 4 byte BLE Access Address identifies the radio telegram type. For advertising frames, the value of the
Access Address is always set to 0x8E89BED6.
4.3 Header
The BLE Header identifies certain radio telegram parameters. Figure 10 below shows the structure of the BLE
header.
4.1 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.
4.2 Access Address
3.2 Default radio transmission sequence
SR-SBP2801-BLE-E transmits telegrams in its standard configuration by using so-called Advertising
Events.
An advertising event is defined as the transmission of the same radio telegram on all selected radio channels
(by default this would be on BLE Channel 37, 38 and 39) one after another with minimum delay in between.
For reliability reasons, SR-SBP2801-BLE-E will send several (minimum two, maximum three) advertising
events for each button input. The resulting transmission sequence is shown in Figure 5 below.
The default interval between the advertising events is 20 ms. Starting with product version DC-06 it is possible
to reduce this interval to 10 ms via the NFC configuration interface. See chapter 6.7.9 for details.
