39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
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---
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tags:
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- bluetooth
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- networks
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---
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# Bluetooth piconet
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Bluetooth devices connect via a micro-network known as a "piconet". Devices
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connect to each other in a master/slave relationship (since renamed
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"central/peripheral").
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Prior to the establishment of a piconet, devices remain in discoverable/scanning
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mode.
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At least one master and one slave is required to make a piconet however a master
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can have multiple slaves simultaneously (e.g. a computer with keyboard, mouse,
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speakers etc).
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The master controls the connection timing and frequency modulation (necessary
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for the Bluetooth protocol) and the slave synchronises its clock with the
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master's. A slave can have its own controls (e.g. a set of headphones with
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playback controls) but it is the master that orchestrates the action.
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What does this mean?
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Take a mouse as a slave that is sending the click data to the master it is
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paired with. The mouse's microcontroller controls the click and what it "means"
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(although this is handled at a level up, in the application layer) but _when_
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the data is processed is managed by the master. The master controls:
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- when devices can transmit
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- what frequency they use
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- the timing and synchronisation of the data exchanged
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So in other words, the mouse waits for the master to give it a timeslot once the
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click has occurred. Then it's data is handed off to the application responsible
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on the master device.
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