9. Timing parameters
9.1. Reset and sleep
After power-up, resetting the module or waking the module from sleep a
is sent to the serial interface as soon as the module is ready for operation.
Description
Typ.
Unit
Ready after reset/sleep
77
ms
9.2. Bluetooth LE timing parameters
The timing parameters for sending advertising packets or scanning are determined by the
user settings
and
. Using these
settings, the advertising interval, the advertising timeout, the scan interval and the scan
window can be configured. Furthermore, the user setting
allows to
configure the timing parameters used during connection setup and connection retention, as
well as the connection interval and the connection supervision timeout.
9.3. Connection establishment
The time needed to establish a connection sums up as the time needed to detect the select-
ed peripheral on air and the time needed for connection parameter negotiation and service
discovery.
Peripheral detection
To establish a connection, the initiating device (central) waits for an
advertising packet, which was sent by the peripheral to which it wants to connect to. As
soon as such an advertising packet has been received, the central sends a connection
request to the chosen peripheral. The time needed to receive this advertising packet
strongly depends on the advertising interval of the peripheral as well as on the scan
interval and scan window of the central (see
Connection parameter negotiation
After the connection request has been sent the central
and peripheral negotiate the timing and security parameters of the connection. To finish
this procedure and discover the services of the peripheral several messages have to
be sent, whereby only one is sent per connection interval (see
Connection type
Estimated number of
exchanged messages
Negotiation time for a
connection interval of 50ms
Unsecured connection
12-14
600-700ms
Secured connection
using the pairing
method
22-24
1100-1200ms
Secured connection to
already bonded device
19-20
950-1000ms
Proteus-III reference manual version 1.3
© August 2020
www.we-online.com/wireless-connectivity
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