Texas Instruments TI Designs Service manual

Ajinder Singh,Natarajan Viswanathan
TI Designs
Wireless Heart Rate Monitor Reference Design
TI Designs Design Features
TI Designs provide the foundation that you need The Wireless Heart Rate Monitor with Bluetooth® low-
including methodology, testing and design files to energy (BLE) is a reference design for customers to
quickly evaluate and customize and system. TI develop end-products for battery-powered 3-channel
Designs help you accelerate your time to market. health and fitness electrocardiogram (ECG)
applications.
Design Resources • Supports 5-Lead ECG applications
• Easily monitor heart rate data through an iOS
Tool Folder Containing Design Files
TIDA-00096 Mobile Application
ADS1293 Product Folder • Powered by a Lithium-ion battery
CC2541 Product Folder
TPS61220 Product Folder • EMI filters integrated in the ADS1293 device reject
Interference from outside RF sources
Small Programmer and Debugger for
CC Debugger Low-Power RF System-on-Chips • Open-source Firmware and iOS application
enables quick time-to-market for customers
Featured Applications
• Health and Fitness
ASK Our Analog Experts
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An IMPORTANT NOTICE at the end of this TI reference design addresses authorized use, intellectual property matters and other
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All other trademarks are the property of their respective owners.
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System Description www.ti.com
1 System Description
The heart of the Wireless Heart Rate Monitor is the ADS1293 device (analog front-end) and the CC2541
device (Bluetooth-low energy SOC) as shown in Figure 1. The ADS1293 device is a highly integrated low-
power analog front-end (AFE) that features three high-resolution ECG channels. The CC2541 system-on-
chip (SoC) adds a BLE wireless feature to the platform. BLE enables seamless connectivity to an iPhone®
or an iPad® through a configurable iOS application that allows an end-user to remotely monitor the heart-
rate data of a patient.
1.1 ADS1293
The ADS1293 incorporates all features commonly required in portable, low-power medical, sports, and
fitness electrocardiogram (ECG) applications. With high levels of integration and exceptional performance,
the ADS1293 enables the creation of scalable medical instrumentation systems at significantly reduced
size, power, and overall cost.
The ADS1293 features three high-resolution channels capable of operating up to 25.6ksps. Each channel
can be independently programmed for a specific sample rate and bandwidth allowing users to optimize the
configuration for performance and power. All input pins incorporate an EMI filter and can be routed to any
channel via a flexible routing switch. Flexible routing also allows independent lead-off detection, right leg
drive, and Wilson/Goldberger reference terminal generation without the need to reconnect leads
externally. A fourth channel allows external analog pace detection for applications that do not utilize digital
pace detection. For the ADS1293 block diagram, see Figure 2.
The ADS1293 incorporates a self-diagnostics alarm system to detect when the system is out of the
operating conditions range. Such events are reported to error flags. The overall status of the error flags is
available as a signal on a dedicated ALARMB pin. The device is packaged in a 5-mm × 5-mm × 0,8-mm,
28-pin LLP. Operating temperature ranges from –20°C to 85°C.
1.2 CC2541
The CC2541 is a power-optimized true system-on-chip (SoC) solution for both Bluetooth low energy and
proprietary 2.4-GHz applications. It enables robust network nodes to be built with low total bill-of-material
costs. The CC2541 combines the excellent performance of a leading RF transceiver with an industry-
standard enhanced 8051 MCU, in-system programmable flash memory, 8-KB RAM, and many other
powerful supporting features and peripherals. The CC2541 is highly suited for systems where ultralow
power consumption is required. This is specified by various operating modes. Short transition times
between operating modes further enable low power consumption.
The CC2541 is pin-compatible with the CC2540 in the 6-mm × 6-mm QFN40 package, if the USB is not
used on the CC2540 and the I2C/extra I/O is not used on the CC2541. Compared to the CC2540, the
CC2541 provides lower RF current consumption. The CC2541 does not have the USB interface of the
CC2540, and provides lower maximum output power in TX mode. The CC2541 also adds a HW I2C
interface.
The CC2541 is pin-compatible with the CC2533 RF4CE-optimized IEEE 802.15.4 SoC. The CC2541
comes in two different versions: CC2541F128/F256, with 128 KB and 256 KB of flash memory,
respectively. For the CC2541 block diagram, see Figure 3.
1.3 TPS61220
The TPS6122x family devices provide a power-supply solution for products powered by either a single-
cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Possible output
currents depend on the input-to-output voltage ratio. The boost converter is based on a hysteretic
controller topology using synchronous rectification to obtain maximum efficiency at minimal quiescent
currents. The output voltage of the adjustable version can be programmed by an external resistor divider,
or is set internally to a fixed output voltage. The converter can be switched off by a featured enable pin.
While being switched off, battery drain is minimized. The device is offered in a 6-pin SC-70 package
(DCK) measuring 2 mm × 2 mm to enable small circuit layout size. For the TPS61220 block diagram, see
Figure 4.
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ADS1293
Analog Front End
CC2541
ADC + uP + BLE
TPS61220
Boost Converter
Battery
www.ti.com Block Diagram
2 Block Diagram
Figure 1. Temperature Transmitter System Block Diagram
2.1 Highlighted Products
The Wireless Heart Rate Monitor Reference Design features the following devices:
• ADS1293
–ADS1293 Low Power, 3-Channel, 24-Bit Analog Front End for Biopotential Measurements
• CC2541
–2.4-GHz Bluetooth™ low energy and Proprietary System-on-Chip
• TPS61220
–TPS6122x Low Input Voltage, 0.7V Boost Converter With 5.5μA Quiescent Current
For more information on each of these devices, see the respective product folders at www.TI.com.
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CH1-ECG
CH2-ECG
CH3-ECG
Lead off
detect
-
+
EMI
filter
CSB
SCLK
SDI
SDO
OSC
IN1
Flexi le
Routing
Switch
Test
Ref
XTAL1
-
+
VSS VDD VDDIO CVREF
RLDINV
RLDIN
EMI
filter
IN2
EMI
filter
IN3
EMI
filter
IN4
EMI
filter
IN5
EMI
filter
IN6
Batt.
Mon
CMOUT
XTAL2
POR
RSTB
DRDYB
RLDREF
RLDOUT
CLK
ALARMB
DIGITAL
CONTROL AND
POWER
MANAGEMENT
Wilson
ref.
CM
Detect
SYNCB
VSSIO
Digital
Filter
Σ∆
Modulator
Digital
Filter
Σ∆
Modulator
-
+
-
+
InA
InA
InA
WCT
-
+CH4- Analog Pace
WILSON_EN CMDET_EN
SELRLD
REF
EMI
filter
EMI
filter
LOD_EN
CH1-Pace
CH2-Pace
CH3-Pace
Digital
Filter
Σ∆
Modulator
REF for
CM & RLD
RLD
Amp.
PACE2
RLDIN
PACE2WCT
WILSON_CN
CH1
CH2
CH3
CH4 InA
Block Diagram www.ti.com
2.1.1 ADS1293
Figure 2. ADS1293 Block Diagram
• Low current consumption:
– Duty-Cycle mode: 120 μA
– Normal mode: 415 μA
• Wide supply range: 2.3 V to 5.5 V
• Programmable gain: 1 V/V to 128 V/V
• Programmable data rates: Up to 2 kSPS
• 50-Hz and 60-Hz rejection at 20 SPS
• Low-noise PGA: 90 nVRMS at 20 SPS
• Dual matched programmable current sources: 10 μA to 1500 μA
• Internal temperature sensor: 0.5°C Error (max)
• Low-drift internal reference
• Low-drift internal oscillator
• Two differential or four single-ended inputs
• SPI™-compatible interface
• 3,5 mm × 3,5 mm × 0,9 mm QFN package
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SFR bus SFR bus
MEMORY
ARBITRATOR
8051 CPU
CORE
DMA
FLASH
SRAM
FLASH CTRL
DEBUG
INTERFACE
RESET
RESET_N
P2_4
P2_3
P2_2
P2_1
P2_0
P1_4
P1_3
P1_2
P1_1
P1_0
P1_7
P1_6
P1_5
P0_4
P0_3
P0_2
P0_1
P0_0
P0_7
P0_6
P0_5
32.768 kHz
CRYSTAL OSC
32 MHz
CRYSTAL OSC
HIGH SPEED
RC-OSC
32 kHz
RC-OSC
CLOCK MUX &
CALIBRATION
RAM
USART 0
USART 1
TIMER 1 (16-bit)
TIMER 3 (8-bit)
TIMER 2
(BLE LL TIMER)
TIMER 4 (8-bit)
AES
ENCRYPTION
&
DECRYPTION
WATCHDOG TIMER
IRQ
CTRL
FLASH
UNIFIED
RF_P RF_N
SYNTH
MODULATOR
POWER ON RESET
BROWN OUT
RADIO
REGISTERS
POWER MGT. CONTROLLER
SLEEP TIMER
PDATA
XRAM
IRAM
SFR
XOSC_Q2
XOSC_Q1
DS ADC
AUDIO / DC
DIGITAL
ANALOG
MIXED
VDD (2.0 - 3.6 V)
DCOUPL
ON-CHIP VOLTAGE
REGULATOR
Link Layer Engine
FREQUENCY
SYNTHESIZER
I2C
DEMODULATOR
RECEIVE TRANSMIT
OP-AMP
ANALOG COMPARATOR
I/O CONTROLLER
1 KB SRAM
Radio Arbiter
FIFOCTRL
SDA
SCL
www.ti.com Block Diagram
2.1.2 CC2541
Figure 3. CC2541 Block Diagram
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Block Diagram www.ti.com
•RF
– 2.4-GHz Bluetooth low energy Compliant and Proprietary RF System-on-Chip
– Supports 250-kbps, 500-kbps, 1-Mbps, 2-Mbps Data Rates
– Excellent link budget, enabling long-range applications without external front end
– Programmable output power up to 0 dBm
– Excellent receiver sensitivity (–94 dBm at 1 Mbps), selectivity, and blocking performance
– Suitable for systems targeting compliance with worldwide radio frequency regulations: ETSI EN 300
328 and EN 300 440 Class 2 (Europe), FCC CFR47 Part 15 (US), and ARIB STD-T66 (Japan)
•Layout
– Few external components
– Reference design provided
– 6-mm × 6-mm QFN-40 package
– Pin-compatible with CC2540 (when not using USB or I2C)
•Low Power
– Active-mode RX down to: 17.9 mA
– Active-mode TX (0 dBm): 18.2 mA
– Power mode 1 (4-µs wake-up): 270 µA
– Power mode 2 (sleep timer on): 1 µA
– Power mode 3 (external interrupts): 0.5 µA
– Wide Supply-voltage range (2 V–3.6 V)
•TPS62730 Compatible low power in active mode
– RX down to: 14.7 mA (3-V supply)
– TX (0 dBm): 14.3 mA (3-V supply)
•Microcontroller
– High-performance and low-power 8051 microcontroller core with code Prefetch
– In-system-programmable flash, 128- or 256-KB
– 8-KB RAM with retention in all power modes
– Hardware-debug support
– Extensive baseband automation, including auto-acknowledgment and address decoding
– Retention of all relevant registers in all power modes
•Peripherals
– Powerful five-channel DMA
– General-purpose timers (one 16-Bit, two 8-Bit)
– IR generation circuitry
– 32-kHz sleep timer with capture
– Accurate digital RSSI support
– Battery monitor and temperature sensor
– 12-Bit ADC with eight channels and configurable resolution
– AES security coprocessor
– Two powerful USARTs with support for several serial protocols
– 23 general-purpose I/O Pins (21 × 4 mA, 2 × 20 mA)
– I2C interface
– Two I/O pins have LED Driving capabilities
– Watchdog timer
– Integrated high-performance comparator
•Development Tools
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www.ti.com Block Diagram
– CC2541 evaluation module kit (CC2541EMK)
– CC2541 mini development kit (CC2541DK-MINI)
– SmartRF™ software
– IAR embedded Workbench™ available
•Software Features
–Bluetooth v4.0 compliant protocol stack for single-mode BLE solution
• Complete power-optimized stack, including controller and host
• GAP – central, peripheral, observer, or broadcaster (including combination roles)
• ATT / GATT – client and server
• SMP – AES-128 encryption and decryption
• L2CAP
• Sample applications and profiles
• Generic applications for GAP central and peripheral roles
• Proximity, accelerometer, simple keys, and battery GATT services
• More applications supported in BLE Software Stack
• Multiple configuration options
• Single-chip configuration, allowing applications to run on CC2541
• Network processor interface for applications running on an external microcontroller
• BTool – Windows PC application for evaluation, development, and test
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Current
Sensor
Gate
Driver
Device
Control
GND
EN
FB
VOUT
L
VREF
VIN
Device
Control
Start Up
VIN
VOUT
Block Diagram www.ti.com
2.1.3 TPS61220
Figure 4. TPS61220 Block Diagram
• Up to 95% efficiency at typical operating conditions
• 5.5 μA quiescent current
• Startup into load at 0.7-V input voltage
• Operating input voltage from 0.7 V to 5.5 V
• Pass-through function during shutdown
• Minimum switching current 200 mA
•Protections:
– Output overvoltage
– Overtemperature
– Input undervoltage lockout
• Adjustable output voltage from 1.8 V to 6 V
• Fixed output voltage versions
• Small 6-pin SC-70 package
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V1
-
+
RLDINV CMOUT
RLDOUT
DIGITAL
CONTROL AND
POWER
MANAGEMENT
Wilson
ref.
Digital
ilter
Σ∆
Modulator
Digital
ilter
Σ∆
Modulator
Digital
ilter
Σ∆
Modulator
-
+
-
+
InA
InA
InA
WCT
-
+
RA LA
LL
RL
IN1
IN2
IN3
IN4
IN5
IN6
R1
R2
C1
I
II
V
SELRLD
WILSON_EN
CM
detect
CMDET_EN
-
+
RLD
Amp.
VSS
VDD
VDDIO XTAL1 XTAL2 CVRE
5V
InA
CH1
CH2
CSB
SCLK
SDI
SDO
DRDYB
ALARMB
RLDIN
RLDRE
CH3
5V 5V
0.1
1 4.096
MHz
0.1
3.3V
0.1
22 p 22 p
CLK
VSSIO
SYNCB
1 MΩ
3.3V
RE for
CM & RLD
1 MΩ
RSTB
3.3V
www.ti.com Theory of Operation
3 Theory of Operation
3.1 5-Lead ECG Application
Figure 5 shows the ADS1293 device in a 5-Lead ECG system setup. The ADS1293 device uses the
Common-Mode Detector to measure the common-mode of the patient’s body by averaging the voltage of
input pins IN1, IN2 and IN3, and uses this signal in the right leg drive feedback circuit.
NOTE: The ideal values of R1, R2and C1will vary per system/application; typical values for these
components are: R1= 100kΩ, R2= 1MΩand C1= 1.5nF.
The output of the RLD amplifier is connected to the right leg electrode, which is IN4, to drive the common-
mode of the patient’s body. The Wilson Central Terminal is generated by the ADS1293 and is used as a
reference to measure the chest electrode, V1. The chip uses an external 4.096MHz crystal oscillator
connected between the XTAL1 and XTAL2 pins to create the clock sources for the device.
Figure 5. 5-Lead ECG Application
CC2541 Communication
The CC2541 device communicates to the ADS1293 device through SPI interface. The CC2541 device
implements the application software to run this application through the 8051 microcontroller core in
addition to running the BLE stack. For additional information, see Section 4.4.
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Theory of Operation www.ti.com
3.2 Battery Life Calculation
For battery life calculations, TI highly recommends that the user reviews CC2541 Battery Life Calculation,
SWRA347.
Comparing the power consumption of a BLE device to another device using a single metric is impossible.
For example, a device gets rated by its peak current. While the peak current plays a part in the total power
consumption, a device running the BLE stack only consumes current at the peak level during
transmission. Even in very high throughput systems, a BLE device is transmitting for only a small
percentage of the total time that the device is connected (see Figure 6).
Figure 6. Current Consumption
In addition to transmitting, there are other factors to consider when calculating battery life. A BLE device
can go through several other modes, such as receiving, sleeping, and waking up from sleep. Even if the
current consumption of a device in each different mode is known, there is not enough information to
determine the total power consumed by the device. Each layer of the BLE stack requires a certain amount
of processing to remain connected and to comply with the specifications of the protocol. The MCU takes
time to perform this processing, and during this time, current is consumed by the device. In addition, some
power might be consumed while the device switches between modes (see Figure 7). All of this must be
considered to get an accurate measurement of the total current consumed.
Figure 7. Current Consumption-Active versus Sleep Modes
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www.ti.com Getting Started
4 Getting Started
4.1 Software
Requirements:
• An iOS device: iPhone 4S and newer generations; iPad 3 and newer generations; fifth generation iPod
(www.Apple.com)
• 3.6-V Lithium-ion battery, recommended model BT-0001
Figure 8. 3.6-V Lithium-Ion Battery
• CC Debugger (http://www.ti.com/tool/cc-debugger)
4.1.1 Installing the Application
The application is not on iTunes (Apple Approved) for download. Download the application from the
following link: TIDA-00096 iOS Application Software .
Since the application is not on iTunes, use the steps below to install it manually. When the application is
distributed manually, there is a limit on how many devices can the application can be loaded on. The
UDID of each device needs to be provided before the application can be installed.
Use the following steps to install the Wireless Heart Rate Monitor application on a device.
1. Connect the iPhone or iPad to the PC.
2. Open the iTunes application on the PC.
3. Wait for iTunes to identify that the device is connected to the PC.
4. The serial number of the device is listed as shown in Figure 9.
Figure 9. Opening iTunes
5. In order to view the Identifier number (UDID), double click on Serial Number as shown in Figure 10
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Getting Started www.ti.com
Figure 10. Finding the UDID Number
6. Report the identifier number (UDID) number to the iPad developer.
7. After the UDID is added to the application (by the iPad developer), a .zip file is sent to the iTunes user
that contains the application to download onto the smart device such as an iPhone4S®, iPhone 5®, or
iPad4®.
8. Unzip the folder to view the application, ecgmonitor.ipa.
9. Open iTunes
Once iTunes is open, use the following steps to install the application on the device.
1. Click the top-left button in the iTunes interface shown in Figure 11.
Figure 11. iTunes library
2. Once the top-left button is clicked, a menu appears, click on Add File to Library (see Figure 12) to
navigate to and select the ecgmonitor.ipa file from the file directory.
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www.ti.com Getting Started
Figure 12. Add File to Library
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Getting Started www.ti.com
3. Go to the iPad page and click on the Apps menu as shown in Figure 13.
Figure 13. Installing the Application on the iOS Device
4. Click on Install and then click Apply. Next, click on Sync. Then finally click Done.
4.2 Hardware
Use to following steps to connect the Demo board.
1. Connect the battery (3.6 V nominal) to the P1 connector on the ADS1293BLE board.
2. Set the U2 switch to the ON position.
3. Uninstall J3.
4. Connect the ECG cable to the J1 connector on the ADS1293BLE board (see Figure 14).
Figure 14. Hardware Setup
5. Connect the five leads to either an ECG simulator or to five electrode pads attached to the body. On
the back of each lead is a label (RL, LL, LA, RA, and V1).
NOTE: For the SKX2000 simulators connect V1 to the C1 terminal. If using the SKX2000 simulator,
turn the simulator on and off by pressing the red button on the left side (see Figure 15).
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www.ti.com Getting Started
Figure 15. ECG Emulator
4.3 Running the Demo
• Open up the ADS1293 ECG monitor application on either an iPad or iPhone.
Figure 16. ECG Monitor Application
• Press the Start Scanning button as shown in Figure 17.
Figure 17. Launch Application
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• After several moments, the ADS1293 ECG Demo START button and the Bluetooth symbol appear as
shown in Figure 18.
NOTE: If the Bluetooth symbol does not appear, close the application and repeat the steps listed in
Section 4.3. If the problem continues, see Section 5 below.
Figure 18. Enable Bluetooth on iOS Device
• The three channel readings are now available on the screen. If the board and ECG simulator are
properly connected, the screen will appear similar to Figure 19 or Figure 20.
–Figure 19 appears when connected to SKX2000 ECG Simulator.
Figure 19. ECG Data Connected to the Simulator
–Figure 20 appears when connected to the body.
Figure 20. ECG Data Connected to the Body
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www.ti.com 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.
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handle (hex) Type (hex) Type Hex / Text Value (default) GATT Server
Permissions Notes
0x10 0x2800 GATT_PRIMARY_SERVICE_UUID 0x2D0D (ECG_SERV_UUID) GATT_PERMIT_READ Start of ECG Profile
Service
10 (properties: notify only)
12 00 (handle: 0x0012)
37 2D (UUID: 0x2D37)
0x12 0x2D37 ECG_MEAS_UUID 00:00:00:00:00:00:00:00:00:00:00:00 (12
bytes) (none) ECG data value
0x13 0x2902 GATT_CLIENT_CHAR_CFG_UUID 00:00 (2 bytes) GATT_PERMIT_READ |
GATT_PERMIT_WRITE
Write "01:00" to enable
notifications. "00:00" to
disable
0x14 0x2901 GATT_CHAR_USER_DESC_UUID "ECG Measurement Data\0" (21 bytes) GATT_PERMIT_READ Characteristic1 user
description
02 (properties: read only)
16 00 (handle: 0x0016)
38 2D (UUID: 0x2D38)
0x16 0x2D38 ECG_NUM_CHANS 03 (1 byte) GATT_PERMIT_READ Number of ECG
Channels
0x17 0x2901 GATT_CHAR_USER_DESC_UUID "Number of ECG Channels\0" (23 bytes) GATT_PERMIT_READ Characteristic3 user
description
02 (properties: read only)
19 00 (handle: 0x0019)
39 2D (UUID: 0x2D39)
0x19 0x2D39 ECG_SAMPLE_SETS 01 (1 byte) GATT_PERMIT_READ Number of ECG Sample
Sets per packet
0x1A 0x2901 GATT_CHAR_USER_DESC_UUID "ECG Sample Sets Per Packet\0" (27
bytes) GATT_PERMIT_READ Characteristic3 user description
08 (properties: write only)
1C 00 (handle: 0x001C)
3A 2D (UUID: 0x2D3A)
0x1C 0x2D3A ECG_COMMAND 00 (1 byte) GATT_PERMIT_READ ECG command set
0x1B 0x2803 ECG_PROFILE_CHARACTER4_UUID GATT_PERMIT_WRITE Characteristic4
declaration
0x15 0x2803 ECG_PROFILE_CHARACTER2_UUID GATT_PERMIT_READ Characteristic2
declaration
0x18 0x2803 ECG_PROFILE_CHARACTER3_UUID GATT_PERMIT_READ Characteristic3
declaration
ECG Peripheral Application: Complete Attribute Table
0x11 0x2803 ECG_PROFILE_CHARACTER1_UUID GATT_PERMIT_READ Characteristic1
declaration
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Figure 21. ECG Peripheral Application: Complete Attribute Table
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ECG Sample1 Data
Running Counter
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4.4.3 ECG Notification Packet
Figure 22 shows an example of captured ECG notification packets.
Figure 22. ECG Notification Packet
Table 1 lists the ECG notification data consisting of 20 bytes and the format.
Table 1. ECG Notification Data Format(1)
Byte Number Default Value Description
0 xxxx Running Counter – High byte
1 xxxx Running Counter – Low byte
2 0xD1 ECG Sample1: Channel 1 ADC High byte
3 0xD2 ECG Sample1: Channel 1 ADC Middle byte
4 0xD3 ECG Sample1: Channel 1 ADC Low byte
5 0xD4 ECG Sample1: Channel 2 ADC High byte
6 0xD5 ECG Sample1: Channel 2 ADC Middle byte
7 0xD6 ECG Sample1: Channel 2 ADC Low byte
8 0xD7 ECG Sample1: Channel 3 ADC High byte
9 0xD8 ECG Sample1: Channel 3 ADC Middle byte
10 0xD9 ECG Sample1: Channel 3 ADC Low byte
11 0xD1 ECG Sample2: Channel 1 ADC High byte
12 0xD2 ECG Sample2: Channel 1 ADC Middle byte
13 0xD3 ECG Sample2: Channel 1 ADC Low byte
14 0xD4 ECG Sample2: Channel 2 ADC High byte
15 0xD5 ECG Sample2: Channel 2 ADC Middle byte
16 0xD6 ECG Sample2: Channel 2 ADC Low byte
17 0xD7 ECG Sample2: Channel 3 ADC High byte
18 0xD8 ECG Sample2: Channel 3 ADC Middle byte
19 0xD9 ECG Sample2: Channel 3 ADC Low byte
(1) The Allowed maximum size of notification packet is 20 bytes.
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4.4.4 Connection Setup
Bluetooth low-energy uses a 20-ms connection interval. Twenty user-data bytes (which is equal to 2-
samples for each channel and 2-bytes running counter) are sent in GATT notifications. Data from
ADS1293 device is ping-pong buffered and up to six notifications are sent every 14 ms based on an OSAL
timer. The ADS1293 sample rate is set as 160 samples/sec (SPS) (see the ADS1293 data sheet,
SNAS602, for more information on R1 = 4, R2 = 5, and R3 = 32). Each sample is 3 bytes and is sending 3
channels.
Firmware Development Platform
One of the development platforms for the CC2541 8051 microcontroller is the IAR development platform.
For information on this platform, goto http://www.iar.com. To communicate to the development platform
through IAR, the CC Debugger is required as shown in Figure 23
The CC Debugger (shown in Figure 23) must be connected to the 10-pin header on the SAT0015 board.
Ensure the notch on the cable that connects to the 10-pin header is towards the outside. If connected
properly, the LED on the CC Debugger lights green.
Figure 23. CC Debugger
Launch the IAR project workspace as shown in Figure 24.
Figure 24. Project Details.
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