Bluetooth Connectivity
8 Bluetooth Connectivity
This communication helps short range transmission of data from medical devices to mobile phones and computers. This feature
in medical devices helps to have contact between the patient and the doctor without having to go to the doctor's office.
8.1 Bluetooth Theory
Bluetooth is an open wireless protocol that creates personal area networks (PANs) and exchanges data over short distances
between fixed or mobile devices. It can connect several devices and overcome problems of synchronization. Bluetooth provides
10 meters of distance to set communication at a speed of up to 1 Mb/s, high compatibility to most computers, and it is not
necessary to implement a special network for communication.
8.1.1 Service Discovery Application Profile (SDAP)
Service discovery protocol (SDP) provides a means for applications to discover what services are available and to determine
characteristics of those available services. A specific service discovery protocol is needed in a Bluetooth environment. The
service discovery protocol defined in Bluetooth specification is intended to address unique characteristics of a Bluetooth
environment.
8.2 Bluetooth Hardware
In this application the LMX9838 Bluetooth serial port module is used. It integrates the Bluetooth 2.0 baseband controller with
2.4 GHz radio, crystal, antenna, and other features. This section explains how to connect this device with the MCU. To power
up the device some filters were implemented to the VCC, VCC_CORE, and VCC_IO pins as shown in Figure 16. It is important
to connect the LMX9838 with adequate ground planes and a filtered power supply. To provide better performance and low
power consumption an external crystal was placed at 32 kHz. The Bluetooth device also provides two pins to connect LEDs
that indicate link status and RF traffic.
Implementing a Glucometer and Blood Pressure Monitor Medical Devices, Rev. 1, 4/2010
Freescale Semiconductor, Inc.
17
FREESCALE [ Freescale ]
