Hardware Reference
In-Depth Information
Value
The characteristic properties for this characteristic are notify only, the char‐
acteristic value handle is
0x0027
, and the characteristic value UUID is the
UUID for Heart Rate Measurement (
0x2A37
).
Handle
0x0027
This attribute contains the characteristic value (see
“Characteristic value at‐
tribute” on page 61
), in this case the heart rate measurement itself. These are the
characteristic value attribute's fields:
UUID
The same UUID present in the last two bytes of the characteristic definition's
attribute value.
Permissions
This attribute's value is neither readable nor writable: a client can obtain its
value only through notifications sent by the server.
Value
The actual heart rate measurement (fictitiously represented in beats per minute
for clarity).
Handle
0x0028
This attribute contains a CCCD (a key descriptor described in
“Client Characteristic
Configuration Descriptor” on page 62
). These are the CCCD attribute's fields:
UUID
The UUID for any CCCD is always the standard 16-bit UUID
CCCD
(
0x2902
).
Permissions
A CCCD must always be readable and writable. The security level required to
execute these operations is defined by the profile or application.
Value
As already established, the CCCD's value is a bitfield, in this case
0x0001
, de‐
noting that notifications are enabled for this particular HRM characteristic.
Handle
0x002A
This attribute contains another characteristic declaration (see
“Characteristic dec‐
laration attribute” on page 59
), this time for Body Sensor Location characteristic.
These are the characteristic declaration attribute's fields:
UUID
The UUID is the standard 16-bit UUID for a characteristic declaration,
UUID
characteristic
(
0x2803
).
