Doc. ID 4374_139 v1.1
Page 19
Chapter 4
System overview
This chapter describes the functionality of the remote controls including how they can be used for
development purposes.
There are two main hardware components in the reference design:
• nRFready Smart Remote 3 DK add-on (nRF6932)
• nRFready Smart Remote 3 nRF52 product example (nRF6937)
See Assemble Smart Remote 3 hardware on page 9 for assembly instructions for the Smart Remote 3 DK add-
on.
Communication in the system is digital and packet-based, which means that data between the remote control
and the host is exchanged as discrete packets of information. The nRF device checks the status of the trackpad
and the keypad matrix before sending this information to the host. The driver on the computer decodes the
packages allowing you to use the remote control as both a pointing device and keypad.
Important: The term host refers to a Bluetooth
®
Smart Ready compliant device which supports the
HID over GATT profile. Windows 10, for instance, natively supports the HID over GATT profile provided
there is Bluetooth
®
Smart Ready hardware connected to the system. A computer with Ubuntu 16.04
LTS, NVS package and Bluetooth
®
4.0 dual-mode (Smart Ready) hardware can also be a host.
For further details on the software and firmware included, consult the firmware documentation, code API, or
the code itself.
4.1 Remote control
The flexibility of the remote control allows you to experiment with your own firmware and functionality. After
pairing, the trackpad, accelerometer, and free-space navigation can be enabled and calibrated.
Important: Gyroscope calibration is performed automatically the first time the firmware is run on the
hardware.
4.1.1 Pairing
When the remote control is turned on, it will attempt to connect to a bonded Bluetooth
®
Smart Ready
compatible master if bonds are available. Otherwise it will be in pairing mode and will wait for connection
from host.
The Smart Remote 3 features the HID over GATT profile and can connect to any Bluetooth
®
Smart Ready host
system supporting this profile. The HID over GATT profile is a direct mapping from the USB HID standard. In
addition to controlling how the HID data is transferred through the wireless link, the profile requires the use
of Bluetooth
®
device security. Security and data encryption are handled by the Bluetooth
®
Security Manager,
which is a Bluetooth
®
Protocol Layer handled by nRF52832. On the master side of the Bluetooth
®
link, the
Security Manager is handled in the Bluetooth
®
driver stack.
If no bonds are stored in flash, the remote control will start to advertise to Smart Ready devices for pairing
when it is turned on. When Smart Remote 3 is in this advertising state, the Bluetooth
®
Host platform should
be instructed to start scanning for and then to connect to it. During this initial connection an encrypted link is
configured by nRF52832 and the host transmits HID commands to the Smart Remote 3 according to the HID
over GATT profile.
The remote control will stay in bond mode for 180 seconds waiting for a Bluetooth
®
connection. If no
connection is established, the remote control will enter deep sleep. Bonding mode will be resumed upon user
activity.
To Next Page
Loading...