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Getting Started
4.4
Firmware
This section describes the over-the-air protocol to be used in the Wireless Heart Rate Monitor Reference
Design. This section also provides an overview of the firmware development platform.
To download the software and firmware, go to
TIDA-00096
.
•
iOS source code
•
CC2541 BLE source code
4.4.1
Communication Overview
ECG data is sent as a burst of six BLE-notification packets every 14 ms. Each notification packet consists
of 20 bytes containing the following:
•
ECG Sample1 (Raw ADC data)
–
Channel1 (3 bytes)
–
Channel2 (3 bytes)
–
Channel3 (3 bytes)
•
ECG Sample2 (Raw ADC data)
–
Channel1 (3 bytes)
–
Channel2 (3 bytes)
–
Channel3 (3 bytes)
An ECG error or status packet is sent once every 17 ECG samples. ECG status packets contain the
following:
•
2-byte running counter
•
Status packet begin indication: 0xFF, 0xFF, 0xFF
•
7-byte error status (ERROR_LOD, ERROR_STATUS, ERROR_RANGE1, ERROR_RANGE2,
ERROR_RANGE3, ERROR_SYNC, ERROR_MISC)
•
Status packet end: 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
4.4.2
ADS1293 ECG Demo: Complete Attribute Table
Figure 21
shows the complete attribute table for the ADS1293 ECG-Demo. Services are shown in yellow,
characteristics are shown in blue, and characteristic values and descriptors are shown in grey. The
ADS1293 ECG demo implements a BLE peripheral device. The Demo supports an ECG peripheral profile
based on the heart rate example of the CC254x Simple BLE Peripheral frame work.
When configured by a peer device, the ECG peripheral application sends notification of the ECG
measurement. On power up, advertising is enabled and the peer device must discover and initiate a
connection procedure to the ECG peripheral. When the peer device configures the ECG measurement for
notification, a timer starts and ECG measurements are sent periodically. In addition to ECG measurement,
the peer device can read the number of ECG channels supported (characteristic 2) and the number of
ECG-sample data sets per packet (characteristic 3).
The peer device may also discover and configure the battery service for battery level-state notifications.
This functionality is the same as supported in Simple BLE Peripheral framework.
17
TIDU195A – January 2014 – Revised July 2014
Wireless Heart Rate Monitor Reference Design
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