Master And Slave - ICP DAS USA BLE-USB User Manual

Usb to bluetooth low energy converter

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Table of Contents

The Broadcaster and Observer has used in the broadcast mode.

1.5.1 Master and Slave

First, there is the concept of Master (Central)/ Slave (Peripheral), which has to do with

establishing a link. This is also known as the GAP role. A Peripheral can advertise, to let other

devices know that it's there, but it's only a Central that can send a connection request to

establish a connection. When a link has been established, the Central is also called a Master,

while the Peripheral could be called a Slave. The Slave only can connect to a Master, but the

Master can connect to three Slaves in our module. The Slave will not be sending broadcast

packet after link has been established.

The Slave has two broadcast patterns. One is the high discoverable mode. The other is low

discoverable mode. The Slave will be broadcasting for 30 second in high discoverable mode,

and the broadcast interval is 20ms for 3 channels. The Slave will be broadcasting for 60 second

in low discoverable mode, and the broadcast interval is 640ms for 3 channels. The Slave will in

the high discoverable mode after power on. If the Slave didn't received connection request from

the Master in high discoverable mode and it will switch to low discoverable mode.

1.5.2 Broadcaster and Observer

The Broadcaster does so by constantly advertising, and the Broadcaster usually has useful data

in the advertising packet. The advertising packet is meant for everyone to see. The Broadcaster

is broadcasting to others, so it never accepts connections. The Observer is the opposite of the

Slave

Master

(Peripheral)

(Central)

Broadcast packet

Connection Request

Link establish

Figure 1-5. The workflow of Bluetooth LE connection

BLE-USB, USB to Bluetooth Low Energy Converter (Ver. 1.0, Oct/6/2016) 9