Bluetooth Client Gatt Profiles; Gatt Calibration Service Workflow - Texas Instruments DLP NIRscan User Manual

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5.3.2 Bluetooth Client GATT Profiles

Once the Bluetooth Client establishes a connection with the DLP NIRscan Nano, the supported GATT
profile is enumerated. DLP NIRscan Nano uses standard Bluetooth Low Energy services for Device
Information (DIS) and Battery (BAS). The rest of the data transfer is through the custom GATT services
and characteristics in the following sections. In the following workflow figures, blue denotes a GATT
service characteristic, while red denotes a DLP Spectrum library routine.
5.3.2.1 Bluetooth Client GATT General Information Service
Once the GATT General Information Service is enumerated, the Bluetooth Client can prompt DLP
NIRscan Nano to read temperature and humidity values. The Bluetooth Client can set a threshold for
temperature and humidity and then subscribe to the temperature and humidity threshold notification. The
Bluetooth Client can also read a device and error status and then subscribe to the device and error status
notifications.
5.3.2.2 Bluetooth Client GATT Date and Time Service
Once the GATT Date and Time Service is enumerated, the Bluetooth Client can write the data and time
values to the DLP NIRscan Nano. It is recommended that the Bluetooth Client sets the date and time
every time a connection is established, so the scan data has the correct date and time stamp.
5.3.2.3 Bluetooth Client GATT Calibration Service
Once the GATT Calibration Service is enumerated, the Bluetooth Client can prompt DLP NIRscan Nano to
download spectrum calibration coefficients, reference calibration coefficients, and reference calibration
matrix. These parameters are unique for each DLP NIRscan Nano and are required for spectrum intensity,
reflectance, and absorbance plots. These parameters must to be downloaded whenever a new DLP
NIRscan Nano is connected to a Bluetooth Client and before a scan is performed. To download these
parameters, the Bluetooth Client must follow these steps:
• Subscribe to the notification of the characteristic UUID that returns the corresponding coefficient.
• Issue a request for the coefficient and wait for the notification to read the corresponding coefficient.
• Once a notification is received, then the Bluetooth Client reads the serialized multiple packets from
DLP NIRscan Nano.
Figure 5-9 shows the workflow for this service.
GATT Calibration Service
enumerated?
No
DLP NIRscan
Nano returns
reference
calibration matrix
in serialized data
format
DLPU030B – June 2015 – Revised July 2015
Submit Documentation Feedback
Subscribe to
Yes
Return
Spectrum
Calibration
Coefficients
notification
Write to
Request
Spectrum
Calibration
Matrix
Figure 5-9. GATT Calibration Service Workflow
Copyright © 2015, Texas Instruments Incorporated
Bluetooth Client App Workflow
DLP NIRscan
Write to Nano returns
Request spectrum
Spectrum calibration
Calibration coefficeints in
Coefficients serialized data
format
DLP NIRscan
Subscribe to
Nano returns
Request
reference
Reference
calibration
Calibration
coefficients in
Matrix
serialized data
notification
format
DLP NIRscan Nano Software
Subscribe to
Return
Reference
Calibration
Coefficients
notification
Write to
Request
Reference
Calibration
Coefficients
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