S42/Central Software User Guide
1VV0301318 Rev. 3
– 2018-08-31
Reproduction forbidden without written authorization from Telit Communications S.p.A.- All Rights Reserved.
Page 62 of 66
10.4.
Update the Connection Parameters
In some cases, the central device will request a connection with a peripheral device containing
connection parameters that are unfavorable to the peripheral device. In other cases, a peripheral
device might have the desire to change parameters in the middle of a connection, based on the
peripheral application. The peripheral device can request the central device to change the
connection settings by sending a “Connection Parameter Update Request”.
This request contains four parameters:
•
minimum connection interval
•
maximum connection interval
•
slave latency
•
timeout
These values represent the parameters that the peripheral device desires for the connection (the
connection interval is given as a range). When the central device receives this request, it has
the option of accepting or rejecting the new parameters.
The S42/Central uses the configuration command AT+LECONPARAM to initiate
the “Connection Parameter Update Request” message or report the current connection
parameter set.
Changing the connection parameter set using the AT+LECONPARAM command effects in the
current connection only. After disconnecting the GATT connection the S42/Central
uses the configured connection parameters (AT+LECONINTMIN, AT+LECONINTMAX,
AT+SLAVELAT, and the calculated connection timeout) for further connections.
To automatically signal a “Connection Parameter Update Request” the S42/Central
uses the command “AT+LECPEVENT=1” that enables the reporting of connection parameter
set changes to the local serial interface.
The S42/Central accepts all valid “Connection Parameter Update Requests” values
of a peripheral device in order to save power consumption for the peripheral device.
10.5.
Connection Examples of Different Use Cases
The following examples will demonstrate Bluetooth LE GATT connections between different
devices to demonstrate the initial connection parameter set and the possibility to monitor or
change these connection parameter set.
