Micro Tracker Reference Guide FW 1.7 V1.1
Page 8 of 39
11th october 2018
Restricted distribution
4.3
BLE (Bluetooth Low Energy) capabilities
The firmware version 1.7 uses the Bluetooth Low Energy (BLE) capabilities of the micro trackers. Devices,
such as Smart-phones, graphical tablets and so on can communicate with the tracker via this interface.
This connectivity can be enabled or disabled via the bit 5 of the
config_flags
parameter.
Smartphones or graphical tablets run the
Client application
and are called
Central device
in this section.
Unless otherwise specified:
➢
all numerical values transmitted through BLE interface shall be in
big endian
.
➢
all string values transmitted through BLE interface shall be composed of unicode characters encoded
with UTF-8.
Note:
1-
Wifi scans can’t be performed while it’s advertising and not bonded, to not disturb bonding process.
Terminology used:
➢
WRITE_CMD
: ATT write command. No answer expected.
➢
WRITE_REQ
: ATT request command. An answer is expected.
➢
WRITE_RESP
: ATT response command.
➢
NOTIFICATION
: ATT notification.
➢
SCAN_REQ
: ATT scan request
.
➢
SCAN_RESP:
ATT scan response.
➢
ERROR_RSP
: ATT error response
➢
READ_REQ
: ATT read request command. An answer is expected.
➢
READ_RESP
: ATT read response.
4.3.1
Advertisement and connection
When the tracker is powered on, it tries to establish a connection with a
central device
. The configured
connection interval depends on its bonding state:
➢
In absence of bond:
✓
tracker sends advertisements each 500ms for 1 minute.
(1)
✓
the buzzer beeps periodically
➢
If the device is bonded but not connected, it sends advertisements each 2 seconds without any
timeout. This lets the client to use the auto-reconnection capability.
Advertisement packets are sent on each of the 3 advertising channels.
Note:
(1)
If the device is not connected within 1-minute delay the BLE module is switch off