s3p8245 arm blood pressure monitor an rev0.00 · pdf file1.4 process of blood measurement in...

S3P8245 ARM Blood Pressure Monitor

Revision 0.00

July 2010

AApppplliiccaattiioonn NNoottee

© 2010 Samsung Electronics Co., Ltd. All rights reserved.

Important Notice

The information in this publication has been carefully checked and is believed to be entirely accurate at the time of publication. Samsung assumes no responsibility, however, for possible errors or omissions, or for any consequences resulting from the use of the information contained herein.

Samsung reserves the right to make changes in its products or product specifications with the intent to improve function or design at any time and without notice and is not required to update this documentation to reflect such changes.

This publication does not convey to a purchaser of semiconductor devices described herein any license under the patent rights of Samsung or others.

Samsung makes no warranty, representation, or guarantee regarding the suitability of its products for any particular purpose, nor does Samsung assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability, including without limitation any consequential or incidental damages.

"Typical" parameters can and do vary in different applications. All operating parameters, including "Typicals" must be validated for each customer application by the customer's technical experts.

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Contact Us: [email protected] TEL: (82)-(31)-209-3865 FAX: (82)-(31)-209-6494

Home Page: http://www.samsungsemi.com

Revision History

Revision No. Date Description Author(s)0.00 June 17, 2010 - Initial draft Xu Hui

Table of Contents

1 OVERVIEW OF ARM BLOOD PRESSURE MONITOR...................................8

1.1 KEY Features of ARM Blood Pressure Monitor...........................................................................................9 1.2 System Block Diagram...............................................................................................................................10 1.3 Principles of Electronic Blood Pressure Monitor........................................................................................10 1.4 Process of Blood Measurement in Blood Pressure Monitor ......................................................................11

2 HARDWARE IMPLEMENTATION .................................................................13

2.1 Analog Signal Processing ..........................................................................................................................13 2.1.1 Introduction to MPS-3117 Pressure Sensor.......................................................................................14 2.1.2 Constant Current Driver Circuit ..........................................................................................................14 2.1.3 Differential amplifier circuit .................................................................................................................15 2.1.4 High Pass Filter Circult: 0.8Hz............................................................................................................16 2.1.5 Amplifier Circuit: 11x...........................................................................................................................17 2.1.6 Low-Pass Filter Circuit: 38Hz .............................................................................................................18 2.1.7 Pulse Rate Trigger Circuit ..................................................................................................................19 2.1.8 Interface between Analog Board and Main Board..............................................................................20

2.2 Microcontroller............................................................................................................................................21 2.2.1 Key Features of S3P8245 ..................................................................................................................22 2.2.2 Resource Assignment ........................................................................................................................23 2.2.3 LCD.....................................................................................................................................................24 2.2.4 Battery Voltage Detect........................................................................................................................24 2.2.5 I2C Device: EEPROM and Real Time Clock......................................................................................25

2.3 Pump Motor Driver Circuit..........................................................................................................................26 2.4 Valve Motor Driver circuit...........................................................................................................................27 2.5 Buzzer Enable and Driver Circuit...............................................................................................................28 2.6 Power Supply Circuit..................................................................................................................................29

3 SOFTWARE IMPLEMENTATION..................................................................30

3.1 Initialization ................................................................................................................................................31 3.2 Battery Voltage Detect ...............................................................................................................................31 3.3 Blood Pressure Monitor .............................................................................................................................33

3.3.1 Overview of Blood Pressure Monitor ..................................................................................................33 3.3.2 Monitor DC and AC Signals of Blood Pressure..................................................................................35 3.3.3 Analysis ..............................................................................................................................................36

3.4 EEPROM Write and Read Operations.......................................................................................................37 3.5 Interrupt Service Subroutine ......................................................................................................................38

3.5.1 Pulse Rate Input ISR ..........................................................................................................................38 3.5.2 User Button (Power On/Off) ISR ........................................................................................................39 3.5.3 User Button (Start, Up/Down, Delete, Save) ISR ...............................................................................40

4 SCHEMATIC ..................................................................................................42

5 PCB LAYOUT ................................................................................................44

6 MEASUREMENT............................................................................................48

6.1 Test Environment.......................................................................................................................................48 6.2 Final Measurement Environment Setting...................................................................................................49 6.3 Test Result .................................................................................................................................................50

7 APPENDIX 1: BILL OF MATERIALS ............................................................51

8 APPENDIX 2: SOURCE CODE......................................................................54

List of Figures

Figure Title Page Number Number Figure 1-1 Types of Blood Pressure Equipments ..................................................................................................9 Figure 1-2 System Block Diagram .......................................................................................................................10 Figure 1-3 DC and AC Components of Blood Pressure Signal and SBP/DBP Position......................................12 Figure 2-1 Analog Board (Driver, Diff-amp, 0.8Hz HPF, 11x Amp, 38Hz LPF, and Comparator) Circuit............13 Figure 2-2 MPS-3117 Pressure Sensor Appearance and Pin Assignment .........................................................14 Figure 2-3 Constant Current Driver and Pressure Sensor...................................................................................14 Figure 2-4 Diff-amplifier Circuit ............................................................................................................................15 Figure 2-5 High Pass Filter Circuit : 0.8Hz...........................................................................................................16 Figure 2-6 Amplifier Circuit : 11x..........................................................................................................................17 Figure 2-7 Low-Pass Filter Circuit : 38Hz ............................................................................................................18 Figure 2-8 Pulse Rate Trigger Circuit...................................................................................................................19 Figure 2-9 Interface between Analog Board and Main Board..............................................................................20 Figure 2-10 Microcontroller Circuit .......................................................................................................................21 Figure 2-11 LCD Function Diagram and External Driving Circuit ........................................................................24 Figure 2-12 Battery Voltage Detect Circuit...........................................................................................................24 Figure 2-13 EEPROM Circuit and Real-time Clock Circuit ..................................................................................25 Figure 2-14 Pump Motor Driver Circuit ................................................................................................................26 Figure 2-15 Valve Motor Driver Circuit.................................................................................................................27 Figure 2-16 Buzzer Enable and Driver Circuit......................................................................................................28 Figure 2-17 Power Supply Circuit ........................................................................................................................29 Figure 3-1 System Flow Chart .............................................................................................................................30 Figure 3-2 Battery Voltage Detect Flow Chart .....................................................................................................32 Figure 3-3 Blood Pressure Monitor Flow Chart....................................................................................................34 Figure 3-4 Monitor DC and AC of BP Flow Chart ................................................................................................35 Figure 3-5 Analysis Flow Chart ............................................................................................................................36 Figure 3-6 EEPROM Write and Read Operation Flow Chart...............................................................................37 Figure 3-7 Pulse Rate Input (External INT0) ISR Flow Chart ..............................................................................38 Figure 3-8 User Button (Power ON/OFF, External INT2) ISR Flow Chart...........................................................39 Figure 3-9 User Button (Start, Up/Down, Delete, Unit, Save, External INT4-7) ISR Flow Chart.........................41 Figure 4-1 Schematic of Analog Board ................................................................................................................42 Figure 4-2 Schematic of Main Board....................................................................................................................43 Figure 5-1 Main Board and Analog Board PCB Assembly (Top Layer)...............................................................44 Figure 5-2 Main Board and Analog Board PCB Assembly (Bottom Layer) .........................................................45 Figure 5-3 Main Board and Analog Board PCB (Top Layer) ...............................................................................45 Figure 5-4 Main Board PCB (Bottom Layer) ........................................................................................................46 Figure 5-5 Final Implementation of Blood Pressure Monitor (Main Board)..........................................................47 Figure 5-6 Final Implementation of Blood Pressure Monitor (Analog Board) ......................................................47 Figure 6-1 Final Measurement Environment Setting ...........................................................................................49 Figure 6-2 Blood Pressure Signals Measurement Waveform..............................................................................50

List of Tables

Table Title Page Number Number Table 2-1 Microcontroller Resource Assignment .................................................................................................23 Table 7-1 Bill of Main Board Materials .................................................................................................................51 Table 7-2 Bill of Analog Board Materials..............................................................................................................53

S3P8245_ARM BLOOD PRESSURE MONITOR_AN_REV 0.00 错误！未定义样式。错误！未定义样式。

8

1 OVERVIEW OF ARM BLOOD PRESSURE MONITOR

This application note describes an arm blood pressure monitor (BPM) based on Samsung's S3P8245 microcontroller. The reference design is intended for novices, who are not familiar with blood pressure monitor system design. You can modify the design to build more complicated applications.

With rising living standards and increase in ageing among people, medical testing equipments have become necessity for families. For instance, home blood pressure equipments have become increasingly popular with the Chinese families.

Usually, these equipments are of two types:

• First is the Mercury sphygmomanometer. The main advantage of such equipment lies in its numerical stability. However, the disadvantages include: patients cannot measure themselves if they are alone; the equipment must be operated by healthcare professionals. This equipment can also result in significant visual observation error. The measurement results can be different, depending on the doctor's experience and criterion, so it can lead to subjectivity. The Mercury sphygmomanometer is bulky and not easy to carry (not portable).

• Second is the electronic Blood Pressure Monitor (BPM). The main advantage of such equipment include: ease of use; patients without any professional training can also use this equipment. It is easy to record the measured values with this equipment. Besides, it is lightweight and portable. Due to its advantages, more families are using this equipment. From 2007 to 2010 alone, China's annual demand for electronic blood pressure monitor grew to 350 million units.

Electronic blood pressure monitor are of two types:

• Wrist blood pressure monitor

• Arm blood pressure monitor


9

Figure 1-1 shows all the above-mentioned blood pressure equipments.

a. Mercury Sphygmomanometer b. Wrist Blood Pressure Monitor c. Arm Blood Pressure Monitor

Figure 1-1 Types of Blood Pressure Equipments

1.1 KEY Features of ARM Blood Pressure Monitor

The key features of arm blood pressure monitor based on Samsung's S3P8245 microcontroller include:

• Measurement: Arm-type

• Measuring range: Pressure: 0 ~ 299mmHg (0 ~ 39.9kPa), Pulse: 40 ~ 180 beats/minute

• Accuracy: Pressure: ±4mmHg (±0.5kPa), Pulse: ±5%

• Pump method: Inflatable pump automatic inflate

• Deflate method: Release valve automatic deflate

• Measurement method: Oscillographic determination method

• Functions:

− User button: Power On/Off, Start, Up/Down, Delete, Save, and Unit − Records up to 35 blood pressure monitoring records − No user button operation; automatic shutdown after 30 seconds

• Power: 4x AA batteries or 6V DC power supply

• Battery life: 200 times measurement

• Operation temperature and humidity: +10 ~ +40; 30%RH ~ 85%RH


10

1.2 System Block Diagram

ADCCons. Cur.

DriverPressureSensor

Diff - Amp2nd OrderHPF : 0.8Hz

2nd OrderLPF : 38Hz

Amplifier11 x

Pulse Rate Trigger

LCD Screen19 SEG * 4 COM

Other User Button

M

M

EEPROM

RTC

Ext. INTBUZ

OSC

LCD

TB

T 1

Battery Vol . CPU

SIOROM

RAM

I/OPWR

Power Mana .

Pump Motor

Valve Motor

Start But .

Power But .

S3P8245

BT+6 V

+5V

10 MHz

32. 768 KHz

ADC0

ADC1

ADC2

INT0INT1 INT2

INT4-INT7

3

2

Main Board V 2.1

Analog Board V 1.0

Note of BPM System BlockBT +6V : Battery +6VPower Mana. : Power ManagementCons. Cur. Driver : Constant Current DriverStart But. : User Button (Start)Power But. : User Button (Power ON/OFF)RTC : Real Timer Clock

V+ V-

: Not used 4

19

Figure 1-2 System Block Diagram

1.3 Principles of Electronic Blood Pressure Monitor

Typically, blood pressure can be described as systolic blood pressure (SBP) and diastolic blood pressure (DBP).

• Systolic blood pressure (SBP): The blood pressure is measured at the time of heart contraction, that is, when blood hits the blood vessels.

• Diastolic blood pressure (DBP): The blood pressure is measured when the heart does not contract. If the cuff pressure is equal to the blood pressure, blood begins to flow and produces a "cuff" sound. The blood pressure is measured at this point (SBP). Once the cuff sound weakens, it gradually disappears. The blood pressure is measured again at this point (DBP).


11

1.4 Process of Blood Measurement in Blood Pressure Monitor

• The process of blood pressure measurement in the blood pressure monitor is described as follows:

• When the patient presses the Start button, the microcontroller opens the inflatable pump motor.

• The BPM system inflates up to 200mmHg. After reaching this value, it slowly deflates with the speed of 5mmHg per second.

• The pressure sensor outputs a signal through differential amplifier.

− One part of signal goes to the ADC0 channel to monitor the DC component of blood pressure signal. − Other part goes to 0.8Hz second order high-pass filter to remove the DC component. − Rest of the AC component of 11x amplification is inputted to the 38Hz second order low-pass filter (to filter

power and skin friction with the cuff of high-frequency noise and frequency interference, and to adjust the signal in the range of 0 to 5V).

− One part of the filtered AC signal is sent to the pulse rate trigger circuit for generating trigger pulses that starts the ADC module operation.

− Other part is sent to the ADC1 channel for calculating the amplitude of AC signal.

• Find the maximum peak-to-peak amplitude. Mark this point as MAP point.

• Before MAP point, determine the value that is the closest to 0.54*MAP. The corresponding DC component value of this transient position specifies the systolic blood pressure (SBP) value.

• After MAP point, determine the point whose value is closest to 0.72*MAP. The corresponding DC component value specifies the diastolic blood pressure (DBP) value.

• By using the internal timer to measure the interval between every two adjacent pulses, the system easily obtains the pulse rate (PR) value.

• All the measurement results will be showed on the LCD screen.


12

Figure 1-3 shows the system operation process, blood pressure, systolic and diastolic blood pressure signals, and their position.

Pump Deflate

SBP

MAPDBP

DC . BP

AC . BP

Figure 1-3 DC and AC Components of Blood Pressure Signal and SBP/DBP Position


13

2 HARDWARE IMPLEMENTATION

2.1 Analog Signal Processing

The blood pressure monitor system needs a filter and an amplify circuit for the purpose of processing weak analog signals and recognizing pulse signals. Such system is made of a single PCB board called the Analog Board. The board provides a constant current driver (for pressure sensor), pre-amplifier (for pressure sensor's output weak signal), high-pass filter, intermediate amplifier, low-pass filter, and pulse signal (which is sent to the MCU).

Figure 2-1 shows a schematic diagram of the Analog Board.

R30 1K ohm 1%R25 1K ohm 1%

R7 1.3M ohm 1%

R131M ohm 1%

R161.3M ohm 1%

R20

2.4K ohm

R21

182K ohm

VCC_+5V

R5 0 ohm

C5104

VCC_+5V

P2.1/ADC1

C4104

VCC_+5V

C2

104

R3 100 ohm 1%

5

67

84

-

+

U2BLM358

3

21

84

-

+

U2ALM358

5

67

84

-

+

U4BLM358

VDIFF

3

21

84

-

+

U4ALM358

C3

104

VLPF

R8 1M ohm 1%

VDIFF

AGND

R9 200K ohm 1%

+ C110uF

R10 200K ohm 1%

P2.0/ADC0

2

37

564 1

8

-

+

U3

LM311

R24

50K ohm

R22

100K ohm 1%

GND

VCC_+5V

2nd Order LPF: 38Hz

2nd Order HPF: 0.8Hz

C7104

Amplifier: 11xPulse Rate Detector

R17 1M ohm 1% R18 1.5M ohm 1% R19 360K ohm 1%

VHPF

C9

104

DC Signal of Blood Pressure (BP)

AC Signal of BP

R34 10M ohm 1%

VCC_+5V

R15 1K ohm 1%

R33 5.1M ohm 1%

R14 1K ohm 1%

R35 1M ohm 1%

Pressure Sensor

C12104

R28 10K ohm 1%R27 1K ohm 1%

VCC_+5VVHPF

VCC_+5V

C13104

R26

10K ohm

VCC_+5V

C10104R31 49.9K ohm 1%

VMAGR32 10K ohm 1%

P0.0/INT0

R29 30K ohm 1%

1 1

6 6

22

33

44

55

U1

MPS-3117-006G_6_SOP

Q19012 R4

1.2K ohm

R14.7K ohm

R2

4.7K ohm

VCC_+5V

123

J4

CON3

C8

104

P1.2/T1PWMR11 30K ohm 1%

C11104

R12 30K ohm 1%

Pulse Rate

R23 100 ohm 1%

R6 1M ohm 1%

+ C610uF

Figure 2-1 Analog Board (Driver, Diff-amp, 0.8Hz HPF, 11x Amp, 38Hz LPF, and Comparator)

Circuit


14

2.1.1 Introduction to MPS-3117 Pressure Sensor

MPS-3117 is a pressure sensor for blood pressure monitor from Taiwan Metrodyne Microsystem Corp. Its dimension is 7mm×7mm×10mm, and its measurable pressure ranges from -299.95mmHg to +299.95mmHg. MPS-3117 uses a constant source to drive the Wien Bridge. It sends the double-ended output differential signals according to the pressure.

Figure 2-2 shows the appearance and pin assignment of MPS-3117 pressure sensor.

Figure 2-2 MPS-3117 Pressure Sensor Appearance and Pin Assignment

2.1.2 Constant Current Driver Circuit

The BPM system requires a constant current source to drive pressure sensor. The typical value of drive current is 1mA while the maximum value of drive current is 3mA.

11

6 6

22

33

44

55

U1

MPS-3117-006G_6_SOP

Q19012 R4

1.2K ohm

R14.7K ohm

R2

4.7K ohm

VCC_+5V

123

J4

CON3

P1.2/T1PWM

Figure 2-3 Constant Current Driver and Pressure Sensor


15

2.1.3 Differential amplifier circuit

In the BPM system, the differential amplifier plays the role of amplifying weak signal output from pressure sensor. One way to do that is directly to the microcontroller as a DC signal of blood pressure. The other signal is provided to the back analog circuits for filtering and amplification processing.

The diff-amplifier circuit output can be calculates as follows:

6 7

11

1 1.3( ) ( ) ( ) ( ) 76.667 ( )30DIFF IN IN IN IN IN IN

R R M MV V V V V V VR k+ − + − + −

+ += × − = × − ≈ × −

R7 1.3M ohm 1%

R131M ohm 1%

R161.3M ohm 1%

R20

2.4K ohm

R21

182K ohm

VCC_+5V

C5104

VCC_+5V

C4104

R3 100 ohm 1%

3

21

84

-

+

U2ALM358

VDIFFVDIFF

+ C110uF

P2.0/ADC0

R11 30K ohm 1%

R12 30K ohm 1%

R6 1M ohm 1%

Figure 2-4 Diff-amplifier Circuit


16

2.1.4 High Pass Filter Circult: 0.8Hz

The analog board of the BPM system uses 2nd order Butterworth high-pass filter circuit, whose transfer function is calculated as follows:

2

2 2 3

8 9 10 2 3 8 9 10 17 18 19 2 3

( ) 1( )( ) ( )( )

HPFSH S C CS S

R R R C C R R R R R R C C

=+

+ ++ + + + + +

C2

104

5

67

84

-

+

U2BLM358VDIFF

C3

104

R8 1M ohm 1% R9 200K ohm 1% R10 200K ohm 1%

R17 1M ohm 1% R18 1.5M ohm 1% R19 360K ohm 1%

VHPF

VCC_+5V

R15 1K ohm 1%R14 1K ohm 1%

Figure 2-5 High Pass Filter Circuit : 0.8Hz

Suppose the network coefficient a11 of 2nd order Butterworth is 1.414 and the angular frequency is 0.8x2π, while the value of both C2 and C3 is 0.1uF. So, the values of R8+R9+R10 and R17+R18+R19 can be calculated as follows:

2 38 9 10

2 3 11

0.1 0.1 1.410.1 0.1 1.414 0.8 2c

C CR R R MC C α ω π

+ ++ + = = = Ω

× × × ×

17 18 19 2 28 9 10 2 3

1 1 2.86( ) 1.41 0.1 0.1 (0.8 2 )c

R R R MR R R C C Mω π

+ + = = = Ω+ + Ω× × × ×


17

2.1.5 Amplifier Circuit: 11x

The signal coming from high-pass filter is weak and needs to amplify. Therefore, the system uses an 11x magnification amplifier circuit.

3

21

84

-

+

U4ALM358

R28 10K ohm 1%R27 1K ohm 1%

VHPF

VCC_+5V

C13104

VMAG

Figure 2-6 Amplifier Circuit : 11x


18

2.1.6 Low-Pass Filter Circuit: 38Hz

System uses 2nd order Butterworth low-pass filter circuit, whose transfer function is calculated as follows:

31 32 29 8 11

2 31 32 29

31 32 29 11 31 32 29 8 11

1( )( ) 1( )

( ) ( )

LPFR R R C CH S R R RS S

R R R C R R R C C

+=

+ ++ +

+ +

Suppose the network coefficient a11 of 2nd order Butterworth is 1.414 and the angular frequency is 38x2π, while the value of both C2 and C3 is 0.1uF. So, the values of R31+R32 and R29 can be calculated as follows:

1131 32

8

1.414 59.338 2 0.1c

R R kC F

αω π μ

+ = = = Ω× ×

29 2 231 32 8 11

1 1 29.3( ) 59.3 0.1 0.1 (38 2 )c

R kR R C C ω π

= = = Ω+ × × × ×

R30 1K ohm 1%R25 1K ohm 1%

P2.1/ADC1

VCC_+5V

5

67

84

-

+

U4BLM358

VLPFR31 49.9K ohm 1%VMAG

R32 10K ohm 1% R29 30K ohm 1%

C8

104

C11104

R23 100 ohm 1%

+ C610uF

Figure 2-7 Low-Pass Filter Circuit : 38Hz


19

2.1.7 Pulse Rate Trigger Circuit

System uses a single, high-speed voltage differential comparator as the pulse rate trigger circuit. The signal, which goes through the RC low-pass filter, will input to the positive side of comparator LM311. More reference voltage is put on the negative side. When the signal is greater than the reference voltage, LM311 will be output high. Otherwise, it holds the low level. Figure 2-8 shows the pulse rate trigger circuit.

VLPF

2

37

564 1

8

-

+

U3

LM311

R24

50K ohm

R22

100K ohm 1%

VCC_+5V

C7104

C9

104

R34 10M ohm 1%R33 5.1M ohm 1%

R35 1M ohm 1%

C12104

VCC_+5V

R26

10K ohm

VCC_+5V

C10104

P0.0/INT0

Figure 2-8 Pulse Rate Trigger Circuit

The reference voltage value is calculated as follows:

24 24

22 24 24

5100CMPREF DD

R RV V VR R k R

= × = ×+ +

By adjusting the potentiometer R24 value, you can select the appropriate reference voltage for pulse rate trigger circuit. The actual value of R24 in this BPM system is 0.745V.


20

2.1.8 Interface between Analog Board and Main Board

There are two interfaces (J8 and J9) between analog board and main board in the BPM system. One is called J9 that includes DC and AC signals of blood pressure and pulse rate trigger signal. Also, J9 provides +5V power, both analog and digital ground. Both analog ground and digital ground is shorted by a 0Ω resistor. The other interface is called J8 that controls the pressure sensor operation status. When P1.2 outputs low level, the sensor turns on, else it turns off.

ON 0Pressure P1.2

OFF 1

P1.2/T1PWM

123

J8

CON3

P2.1/ADC1P2.0/ADC0

123456

J9

CON6

P0.0/INT0AGND

VCC_+5V

AGNDR82 0 ohm

GND

Figure 2-9 Interface between Analog Board and Main Board


21

2.2 Microcontroller

In the reference design, Samsung’s S3P8245 is used as the microcontroller. The main function of this microcontroller is to control both pump motor and valve motor, acquire and process both DC and AC of analog signal, respond the pulse trigger and user button, and then display on the LCD screen.

The second function of this microcontroller is power management, record monitored results, and alarm patients via buzzer.

P4.0/SEG16

P4.1

/SEG

17P4

.2/S

EG18

SEG

9

R15 100K ohm

VCC_+5V

P4.3

/SEG

19

SEG

4

P4.4

/SEG

20

VLC0

P4.5

/SEG

21

P5.0

/SEG

24P5

.1/S

EG25

P5.3/SEG27P5.2/SEG26

P5.4/SEG28P5.5/SEG29P5.6/SEG30P5.7/SEG31

P4.6

/SEG

22

11

22

33

44

55

66

77

88

99

1010

1111

1212

1313

1414

1515

1616

1717

1818

1919

2020

2121

2222

2323

KPammHg

次/分

高压

低压

心

率

U2

BPMLCD_00598

P3.0/TBPWMP3.1P3.2P3.3P3.4

P4.7

/SEG

23

SEG15

VDD

SEG

8

XOUTXIN

VCC_+5V

VCC_+5V

TESTXTINXTOUTRESETP0.0/INT0

SEG

5

Y210MHz

R17 0 ohm

+

C13

10uF

R14

100K ohm

P0.5

/INT5

C14

103

P0.6

/INT6

SEG

7

SEG14

P0.7

/INT7

P1.0

R13

100K ohm

P1.1

P1.2

/T1P

WM

P1.3

P1.4

/BU

ZP1

.5/S

OP1

.6/S

CK

SEG

6

P1.7

/SI

P2.0

/AD

C0

P2.1

/AD

C1

SEG[0...18]

VCC_+5V

SW6KEY2

P2.2

/AD

C2

R24

10K ohm

C17

104

P0.1/INT1

P2.3

/AD

C3

SEG

6P2

.4/A

DC

4

SEG13

CO

M3

R16 50 ohm

SEG

7

P2.5

GND

P2.6P2.7

AVREF

GND

AVSS

SEG12

CO

M2

CBCA

VLC1

+C10

100uF

C8

104

C12 0.1uF

SEG

8

SEG

0

COM0COM1COM2COM3

P0.5/INT5P0.6/INT6P0.7/INT7

1234

J4

CON4

P0.4/INT4

SEG0

CO

M1

SEG1VCC_+5V

SEG2SEG3SEG4

SEG

9

SEG

1

CO

M0

SEG5SEG26/P5.21

SEG27/P5.32

SEG28/P5.43

SEG29/P5.54

SEG30/P5.65

SEG31/P5.76

P3.0/TBPWM7

P3.1/TAOUT/TAPWM8

P3.2/TACLK9

P3.3/TACAP/SDAT10

P3.4/SCLK11

VDD12

VSS13

XOUT14

XIN15

TEST16

XTIN17

XTOUT18

RESET19

P0.0/INT020

P0.

1/IN

T1

21

P0.

2/IN

T2

22

P0.

3/IN

T3

23

P0.

4/IN

T4

24

SEG

25/P

5.1

80

P0.

5/IN

T5

25

P0.

6/IN

T6

26

P0.

7/IN

T7

27

P1.

0/T1

CAP

28

P1.

1/T1

CLK

29

P1.

2/T1

OU

T/T

1PW

M30

P1.

331

P1.

4/BU

Z32

P1.

5/SO

33

P1.

6/SC

K34

P1.

7/SI

35

P2.

0/AD

C0

36

P2.

1/AD

C1

37

P2.

2/AD

C2

38

P2.

3/AD

C3

39

P2.

4/AD

C4

40

P2.5/ADC541P2.6/ADC6 42P2.7/ADC7/VVLDREF 43AVREF44AVSS 45CB 46CA47VLC0 48VLC1 49VLC2 50COM0 51COM1 52COM2 53COM3 54SEG055SEG1 56SEG2 57SEG358SEG4 59SEG5 60

SEG

661

SEG

762

SEG

863

SEG

964

SEG

1065

SEG

1166

SEG

1267

SEG

1368

SEG

1469

SEG

1570

SEG

16/P

4.0

71S

EG17

/P4.

172

SEG

18/P

4.2

73S

EG19

/P4.

374

SEG

20/P

4.4

75S

EG21

/P4.

576

SEG

22/P

4.6

77S

EG23

/P4.

778

SEG

24/P

5.0

79

S3P8245

(80-TQFP-1212)

U4

S3P8245_80_TQFP

R23

10K ohm

P4.2/SEG18

C18

0.1uF

P0.1

/INT1

1 2SW5 SW KEY-SPST

SEG

2

SEG

10

P0.2

/INT2

Y332.768KHz

C15 33pF

C16 33pF

P4.1/SEG17

P0.3

/INT3

SEG

10

C7 33pF

SEG

11SE

G12

SEG

3

C11 33pF

SEG

11

P0.4

/INT4

SEG

13

R10

100K ohm

SEG

14SE

G15

P4.0

/SEG

16

VLC2

Figure 2-10 Microcontroller Circuit


22

2.2.1 Key Features of S3P8245

The key features of S3P8245 include: • Memory

− 16Kbytes One-time-program (OTP) ROM − 544 bytes of data memory (RAM)

• 45 I/O (Sharing with LCD signal outputs)

• Interrupts

− 6 level, 8 vector, 8 internal interrupts − 2 level, 8 vector, 8 external interrupts

• Timer

− Watch Timer for real-time and interval time measurement, clock generation for LCD and buzzer. − 8-bit Timer/Counter A/B, Timer B can generate the carrier frequency − 16-bit Timer/Counter 0/1

• 32 seg * 8 com LCD Controller/Driver

• 10-bit Analog to Digital Converter * 8 channels

• SIO * 1 channel

• Operating Temperature Range: -25 to 85

• Operating Voltage Range: 1.8V to 5.5V

• Package Type : 80-QFP-1420C, 80-TQFP-1212


23

2.2.2 Resource Assignment

Table 2-1 Microcontroller Resource Assignment

No. Function Module Assignment Pin Note

1 DC & AC Signal of

Blood Pressure Detector

ADC One channel ADC for DC signal of BP; Other channel for AC signal of

BP

P2.0/ADC0 (#36), P2.1/ADC1 (#37)

2 channel

Timer Timer 0 generates 5ms interval - - 2 Pulse Rate

Detector Interrupt Rising edge trigger, calculate PR

@ ISR P0.0/INT0 (#20) -

3 LCD display LCD 4COM * 19 SEG COM0-3(#51-54), SEG0-18(#55-73)

-

Interrupt Rising edge trigger, ON/OFF @ ISR P0.2/INT2 (#22) -

I/O Output high level to enable GM6155-5.0 P0.3 (#23) -

4 Power Management

Timer

Updates the over-time counter every 5ms. If the system is waiting

for over-time, no button is pressed.

- -

5 User Button Interrupt Falling edge trigger, execute

function (Start, Up/Down, Delete, Unit, Save) @ ISR

P0.1/INT1 (#21), P0.4/INT4 ~

P0.7/INT7 (#24-27)

Up to 5 channels

Timer Timer 1 is set in the PWM mode to control the pump speed - -

6 Pump Motor I/O

Motor control 0-1, support function:

Start/ Forward/ Reverse/ Stop P1.0-P1.1 (#28-29) -

7 Valve Motor Timer Timer B is set in repeating mode to control the valve speed P3.0/TBPWM (#7) -

8 EEPROM I/O One I/O for power control; Other two I/O for I2C clock and data P2.5-P2.7 (#41-43) -

9 RTC I/O Two I/O for I2C clock and data P3.3-P3.4 (#10-11) Not used

Buz Generates the carrier frequency of buzzer P1.4/Buz (#32) -

I/O Enables the buzzer output P1.3 (#31) - 10 Buzzer

Timer Timer A is set in the PWM mode to control the buzzer output time - -

11 Battery Vol. Detector ADC One ADC channel for battery

voltage P2.2/ADC2 (#38) -


24

2.2.3 LCD

The internal LCD module in S3P8245 can directly drive up to 128-dot (32 segments × 4 commons) LCD panel. The internal resistor bias can provide 1/2 bias, 1/3 bias, and 1/4 bias, without any bias pin or off chip resistor.

S3P8245 supports two kinds of LCD voltage driving circuit, that is, internal and external. This solution uses external LCD voltage driving circuit.

The LCD panel used can display systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse rate (PR), diagnose result, and other system status (such as battery under-voltage). The drive method is +5V, 1/4 duty, and 1/3 bias.

Figure 2-11 LCD Function Diagram and External Driving Circuit

2.2.4 Battery Voltage Detect

Battery voltage is measured through R30 and R29 to ground. The relationship between voltage of P0.2/ADC2 port and battery voltage is as follows:

292

29 30

10 0.66210 5.1ADC BAT BAT BAT

R kV V V VR R k k

= × = × ≈ ×+ +

When the battery voltage drops to 4.8V, the voltage of ADC2 input is about 3.179V. After battery voltage resumes to 5.1V, the voltage of ADC2 increases to 3.377V.

R29 10K ohm

C20 104 P2.2/ADC2

R30 5.1K ohm VCC_+6V

Figure 2-12 Battery Voltage Detect Circuit


25

2.2.5 I2C Device: EEPROM and Real Time Clock

The system uses a two-wire EEPROM 24C01 as blood pressure monitored data memory unit. Three I/O ports (P2.5 ~ P2.7) are used to control this device. One is used to control the power supply when EEPROM is not used during the main software process. Other two ports are the serial data and clock line between the MCU and EEPROM interfaces.

Even though the final system does not use the RTC, this interface is used for hardware and software upgrades. The system remains real-time clock circuit for high-resolution time and date application. The PCF8563 is a CMOS real-time clock/calendar optimized for low power consumption. A programmable clock output, interrupt output, and voltage-low detector are also provided. All addresses and data are transferred serially via a two-line bidirectional I2C bus. Its maximum bus speed is 400 kbit/s. The built-in word address register is incremented automatically after each written or read data byte.

P2.7

R21

20K ohm

R2220K ohm

R20 100 ohmP2.5

A01

A12

A23

VSS4 SDA 5SCL6WP 7VCC 8

U5

24C01_8_DIP

VCC_+5V

R18 10K ohmQ2

9012

P2.6

C9 CAP

OSCI1

OSCO2

INT3

VSS4

SDA5SCL 6CLKOUT7VDD 8

U3

PCF8563_8_DIP

C6

104

VCC_+5V

C5

CAP VRY132.768KHz

R7

20K ohm

P3.3

R11

20K ohm

P3.4

Figure 2-13 EEPROM Circuit and Real-time Clock Circuit


26

2.3 Pump Motor Driver Circuit

The BPM system has a 6V DC motor for cuff inflation. The scope of internal air pressure is restricted to measure blood pressure (170 ~ 200mmHg). This driver circuit uses symmetry bridge type to support three motor modes, including start, stop, forward, and reverse modes.

VCC_+6V

Q89013

R35

1K ohm

Q99013R39

1K ohm

R32

1K ohmQ59012

R38

1K ohm

P1.1

D11N4007 D2

1N4007+ C23

10uFC25104

1 2

MG1

MOTOR AC

R31

1K ohm

Q49012

R33

1K ohm

R34

1K ohmR36

1K ohm

P1.0

Q69013

Q79013

Figure 2-14 Pump Motor Driver Circuit


27

2.4 Valve Motor Driver circuit

The BPM system uses a 6V DC motor for cuff deflation called valve motor. Use the timer B PWM output waveform to control the speed of deflation.

Q109013

R45

10K ohm

P3.0/TBPWM

VCC_+6V

12

MG2MOTOR

R42

1K ohm

R43

0 ohm

C26 104

D31N4007

Figure 2-15 Valve Motor Driver Circuit


28

2.5 Buzzer Enable and Driver Circuit

When the User button is pressed (or system error occurs during measurement), the system will generate a buzzer sound to grab the patient's attention. S3P8245 supports four kinds of frequencies for buzzer output. Therefore, one I/O port connected through the buzzer module is used to control the buzzer frequency. The other I/O port is used to enable or disable the buzzer output.

R19

1K ohm

VCC_+5V

R25

10K ohmP1.3

R27

0 ohm

LS1

Buzzer

Q39012

R26

1K ohm

R28

1K ohm

12

J3

CON2

+C19

47uF

P1.4/BUZ

Figure 2-16 Buzzer Enable and Driver Circuit


29

2.6 Power Supply Circuit

GM6155-5.0 is an efficient linear voltage regulator with ultra low noise output, extremely low dropout voltage, and extremely low ground current. The EN pin (#3) in this regulator controls the VOUT pin (#5), which supplies power to the MCU.

When EN is low, VOUT has no output. On the contrary, when EN is high, VOUT outputs +5V power. After pressing Key1 (Power ON/OFF user button), the +6V battery voltage is sent to ground through R37, SW7, D4, and R46. The voltage of R46 is about 3.97V. When EN is high, VOUT will start to output +5V power to the microcontroller. During the system initialization process, after the microcontroller starts operation, P0.3 outputs high level. Then regardless of whether Key1 continues to be pressed or released, the EN pin will always be high and the system will work properly. After that, if you press the Key1 again, the +6V battery voltage is sent to ground through R37, SW7, and R40. The voltage of R40 will quickly rise to 3.97V and the diode D4 is off, leading to a rising edge on the external interrupt input port P0.2/INT2.

After the MCU responds to this interrupt, P0.3 output low level, diode D6 is off and EN will be directly shorted to ground through R46. As a result, VOUT will stop the output power supply to microcontroller. The system will enter the power-down mode.

Figure 2-17 shows the power supply circuit of this blood pressure monitor system.

C27

104

R37

5.1K ohm

VIN1

GND2

EN3

BYP4

VOUT5

U8

GM6155-5.0ST25R_5_SOT-25

+C22

470uF

C24

104P0.2/INT2

R46

10K ohm

R40

10K ohmVCC_+5V

R41 100 ohm

VCC_+6V

D5 LED

VCC_+5V

R44330 ohmD6

1N4007

C21

104

P0.3/INT3

SW7KEY1

12

J6

CON2

12

J5

CON2

12

J7

CON2

D41N4007

VCC_+6V

+C28

100uF

C29

104

Figure 2-17 Power Supply Circuit


30

3 SOFTWARE IMPLEMENTATION

Figure 3-1 shows the system flow chart with sequence of events in the software. After the microcontroller and system initializes, if the Start button is pressed, the software enters the main loop. Battery voltage detect is used for monitoring the battery voltage. The Blood Pressure Monitor starts a new blood pressure measurement for the patient. After that, the software will respond to external user button operation, and execute the corresponding function. When the system is waiting for User button out of time, the software will automatically shut down the power supply.

Start

System Initialization (MCU, Variable, LCD)

Start Button is pressed?

Battery Voltage Detect

Blood Pressure Monitor (SBP, DBP, PR)

System is Over-time?

User Button Service (Up/Down, Delete, Save)

Start Button is pressed?

Switch off System Power

End

Battery Vol. isUnder- voltage?

Y

N

Y

N

Y

N

Y

N

Figure 3-1 System Flow Chart


31

3.1 Initialization

Initialization involves three parts:

• First, initialize the microcontroller. All the function modules and control registers should be set to their proper values.

• Second, initialize the system variables.

• Third, initialize the LCD, clear the display RAM area, and initialize all the LCD variables. Additionally, the record data stored in the EEPROM should be read out before it is displayed on the LCD screen.

3.2 Battery Voltage Detect

After the Start button is pressed, the system will enter in the main routine.

• First, execute the battery voltage detector. The ADC channel #2 in S3P8245 is configured for battery voltage detection.

• If the voltage value is lower than 4.9V, the software will set under-voltage flag (nSysFlag.6) and toggle the low

battery voltage label " " on the LCD screen.

• Even if the voltage value is below 4.8V, the system will immediately turn off the power.

• On the other hand, if the battery voltage is up to 5.1V or more, the software will automatically clear the under-voltage flag (nSysFlag.6) and turn off the corresponding label on the LCD screen.


32

Start

Enanle ADC2 forBattery Vol Sampling

Set Under-voltage flagnSysFlag.6

Switch off System power

End

Battery Vol.ls= 4.8V?

Y

N

Y

N

Y

N

Toggle Low Bat Vol.label on LCD Screen

Clear Under-voltage flagnSysFlag.6

Turn OFF Low Bat. Vol.label on LCD Screen



Figure 3-2 Battery Voltage Detect Flow Chart


33

3.3 Blood Pressure Monitor

This subroutine will complete a blood pressure measurement process for patient.

3.3.1 Overview of Blood Pressure Monitor

After initialization, the software inflates the pressure value to 200mmHg. The release valve remains closed during this time. It then starts to exhaust the gas. Two seconds later, the external interrupt port 0 is enabled in order to respond to the pulse signal.

In the ensuing process, the system monitors both DC signal and AC signals of blood pressure. As soon as the software deflates the pressure value to 50mmHg, the system will end deflation. The pulse signal triggers the ADC start operation. The software receives the effective DC and AC values of current cycle, that is, an effective pulse signal. It can record up to 40 times of this effective pulse signal.

The software analyzes and diagnoses all monitored data. The final results are displayed on the LCD screen.


34

Start

Initialization

Enable ADC0/1(nSysFlag.0)?

Stop Valve

End

N

Y

N

Start Pump & OFF Valve

Pressure is= 200mmHg

Stop Pump & Start Valve

Delay 2s

Enable Pulse Rate input interrupt (INT0)

Monitor DC & AC of BP

Pressure is= 50mmHg?

Monitor Time is= 40?

Analysis Monitor Results

Diagnose

Display SBP,DBP & PRvalue on LCD

Delay 400ms

System is Over-time?

Y

N

N

Y

Y

Y

N

Figure 3-3 Blood Pressure Monitor Flow Chart


35

3.3.2 Monitor DC and AC Signals of Blood Pressure

The subroutine monitors both DC and AC signals of blood pressure. Calculate the AC signal's peak-to-peak value between two adjacent effective pulses. Determine the maximum and minimum values, and calculate the difference between the two peaks. At the same time, the software will calculate the average DC signal value during the two pulses.

Start

Monitor ADC0(DC Of BP) & ADC1(AC of BP)

Enable ADC0/1(nSysFlag.0)?

Monitor DC & AC of BP

Update DC/AC Sampling Time

Sampling Time is Over-time?

Save to AC String Buffer

End

Y

Y

N

Amplitude-limit Filter for DC of BP

Update Max. /Min./Sum. DC value of BP

Update Max. /Min. AC value of BP

Save to DC String Buffer

Set ADC0/ADC1 enable flag (nSysFlag.0)

Set Cur. Monitor Result valid flag (nSysFlag.2)

N

Figure 3-4 Monitor DC and AC of BP Flow Chart


36

3.3.3 Analysis

The subroutine analyzes the obtained DC and AC values of blood pressure to determine the SBP and DBP points.

• First, find the largest peak-to-peak value in AC data buffer. Mark this point as MAP point.

• Second, search the point whose value is the closest to 0.54*MAP. This point is located in front of the MAP point. The corresponding average value in DC data buffer specifies the systolic blood pressure (SBP) value.

• Search the point whose value is the closest to 0.72*MAP. This point is located behind the MAP point. The corresponding average value of DC data specifies the diastolic blood pressure (DBP) value.

• Finally, the PR value for patient can be determined by analyzing the entire pulse rate (PR) data.

Start

Find Max. AC of BP

Find preceding point w hich is c lose to 0 .54 *M ax . AC

End

C alculate 0.54*Max. AC of BP

C alculate Practical SBP

C alculate 0.72*Max. AC of BP

Find subsequent point w hich is c lose to 0.72 *M ax. AC

C alculate Practical DBP

C alculate Practical PR

Figure 3-5 Analysis Flow Chart


37

3.4 EEPROM Write and Read Operations

The system uses two wires EEPROM 24C01(1K, 128*8) as storage unit, which can record up to 35 blood pressure monitor results, including SBP, DBP, and PR values. 24C01 is an EEPROM chip with I2C interface. Read and write operations on the bytes have a special definition, as follows:

W rite S ta rt

V a rib les In itia l iza tion

S end C on tro l B yte (1010xxx0B)

R ece ive A C K S igna l?

S end D a ta to E E P R O M(xxxxxxxxB )


S end S T OP S igna l

W rite E nd


Y

Y

Y

N

S end S T A R T S igna l

S end W ord A dd ress (0xxxxxxxB)

D e lay 5m s

N

N

Read Start

Varibles Initialization

Send Control Byte (1010xxx0B)

Receive ACK Signal?

Re-send START Signal

Send STOP Signal

Read End

Receive ACK Signal?

Y

Y

Y

N

Send START Signal

Send Word Address (0xxxxxxxB)

Delay 5ms

N

N

Send Control Byte (1010xxx1B)

Receive ACK Signal?

Read Data from EEPROM

Figure 3-6 EEPROM Write and Read Operation Flow Chart


38

3.5 Interrupt Service Subroutine

The BPM software has several important interrupt service subroutines (ISR), including pulse rate input ISR and user button ISR.

3.5.1 Pulse Rate Input ISR

The subroutine can calculate the pulse rate and set (or clear) ADC0/ADC1 enable flag corresponding to different conditions. Figure 3-7 shows the flow chart of this interrupt service routine.

ISR Enter

Clear Ext. INT0 pending bit

First Time Enter Ext.INT0?

ISR Return

Y

N

Y

N

Y

N

Delay 2ms (for S/W debounce)

P0.0/INT0 is high level?

Clear Timer 0 Counter

Calculate PR & Save to PR Buffer

Monitor Process is Start?

Clear ADC0/ADC1 En. Flag (nSysFlag.0)

Set Monitor Process Start Flag (nSysFlag.1)

Set ADC0/ADC1 En. Flag (nSysFlag.0)

Toggle ADC0/ADC1 En. Flag (nSysFlag.0)

Clear Over-time Counter

N

Figure 3-7 Pulse Rate Input (External INT0) ISR Flow Chart


39

3.5.2 User Button (Power On/Off) ISR

If the user power on/off button is pressed, the software will execute this subroutine. Only when the P0.2 remains high level for more than 40ms, the system will be able to determine if this is a valid key. Then you can turn off the power. The goal is to remove noise interference on P0.2. This way the system cannot be misused.

ISR Enter

Clear Ext.INT2 pending bit

P0.2 is high level?

Delay 20ms(for S /W debounce)

Enable Timer A & Start Buzzer Output

ISR Return

N

N

Update User Button Valid Counter (nkeyflag)

Button Valid Time is = 2?

Toggle Special User Button Pressed Flag (nKeyInfo.2)

Switch off System Power

Set User Button Pressed Flag (nKeyInfo.0)

Clear User Button Pressed Flag (nKeyInfo.0)

Re-read P0.2 Time = 3?

Y

Y

Y

N

Figure 3-8 User Button (Power ON/OFF, External INT2) ISR Flow Chart


40

3.5.3 User Button (Start, Up/Down, Delete, Save) ISR

There are up to five user buttons in this system, namely, start, up/down, delete, unit, and save. Determine whether a valid button is pressed.

• Using the Start button, you can start or stop the monitoring process during measurement.

• Using the up/down button, you can view the prior monitoring values recorded in the EEPROM.

• Using the Delete button, you can delete the currently displayed records.

• Using the Unit button, you can choose the correct pressure unit such as mmHg or kPa.

• Using the Save button, you can save the latest "valid" monitor results.


41

ISR Enter

Clear Ext.INTn pending bit

P0.n is low level?

Delay 20ms(for S/W debounce)

Set Special User Button Pressed Flag (nKeyInfo.n)

ISR Return

N

N

Update User Button Valid Counter (nkeyflag)

Button Valid Time is = 2?

Set User Button Pressed Flag (nKeyInfo.0)

Enable Timer A & Start Buzzer Output

Clear Over-time CounterClear User Button Pressed Flag (nKeyInfo.0)

Re-read P0.n Time = 3?

Y

Y

Y

N

Note:n: 1,4 ~ 7

Figure 3-9 User Button (Start, Up/Down, Delete, Unit, Save, External INT4-7) ISR Flow Chart


42

4 SCHEMATIC

Figure 4-1 Schematic of Analog Board


43

Figure 4-2 Schematic of Main Board


44

5 PCB LAYOUT

Figure 5-1 Main Board and Analog Board PCB Assembly (Top Layer)


45

Figure 5-2 Main Board and Analog Board PCB Assembly (Bottom Layer)

Figure 5-3 Main Board and Analog Board PCB (Top Layer)


46

Figure 5-4 Main Board PCB (Bottom Layer)


47

Layout Guide

1. ADC0 and ADC1 are extremely sensitive signals in the BPM system. Therefore, they should be protected by using ground lines.

LCD Screen

ValveMotor

PumpMotor

Buzzer EEPROM

User Button Analog Board Inferface

Power Managment

+6V

GNDMCUS3P8245

BPM Main BoardV2.1

Figure 5-5 Final Implementation of Blood Pressure Monitor (Main Board)

CCS PS PRTDiff-AMPHPF AMP LPF

Analog Board Interface BPM AB V1.0

Note:CCS: Constant Current Source; PS: Pressure SensorDiff-AMP: Differential Amplifier; AMP: 11x AmplifierHPF: 0.8Hz High-pass Filter; LPF: 38Hz Low-pass Filter; PRT: Pulse Rate Trigger

Figure 5-6 Final Implementation of Blood Pressure Monitor (Analog Board)


48

6 MEASUREMENT

6.1 Test Environment

The test environment comprises the following: • Power supply: +6V DC power or 4x AA batteries

• Temperature: 25

• Equipments:

− Agilent E3648A DC Power Supply (Optional) − Tektronix TDS3034B Digital Phosphor Oscilloscope


49

6.2 Final Measurement Environment Setting

Figure 6-1 shows the final measurement environment setting of the BPM reference solution.

Cuff for Patient

Main Board of BPM

4x AA Battery Power

Analog Board of BPM

6V DC Valve Motor

6V DC Pump Motor

Patient’s Arm

Figure 6-1 Final Measurement Environment Setting


50

6.3 Test Result

Figure 6-2 shows the real measurement of blood pressure waveform by using this BPM reference solution.

MAP

SBP

DBP

DC . BP

AC . BP

PR

Pump Deflate

Figure 6-2 Blood Pressure Signals Measurement Waveform


51

7 APPENDIX 1: BILL OF MATERIALS

Table 7-1 Bill of Main Board Materials

Item Quantity Reference Value Comments 1 1 U2 4COM×19SEG LCD

2 1 U3 PCF8563 RTC, 8-SOP

3 1 U4 S3P8245 80-TQFP

4 1 U5 24C01 EEPROM, 8-SOP

5 1 U8 GM6155-5.0 SMD SOT-25

6 1 MG1 - 6V Pump Motor, 2-SIP

7 1 MG2 - 6V Valve Motor, 2-SIP

8 2 Y1, Y3 32.768 KHz Quartz crystal

9 1 Y2 10 MHz Quartz crystal

10 4 Q2, Q3, Q4, Q5 9012 SMD SOT-23

11 5 Q6, Q7, Q8, Q9, Q10 9013 SMD SOT-23

12 5 D1, D2, D3, D4, D6 1N4007 SMD DO-214AC

13 1 D5 LED SMD 1206

14 2 SW6, SW7 Button -

15 1 LS1 Buzzer -

16 1 J3 CON2 2-SIP

17 3 J5, J6, J7 CON2 Power Connector

18 1 J4 CON4 4-SIP

19 1 J8 CON3 3-SIP

20 1 J9 CON6 6-SIP

21 1 C5 Variable CAP 2-DIP

22 12 C6, C8, C12, C17, C18, C20, C21, C24, C25, C26, C27, C29 0.1uF SMD 0805

23 4 C7, C11, C15, C16 33pF SMD 0805

24 1 C9 CAP 2-DIP

25 2 C10, C28 100uF/10V SMD Tantalum Capacitor


27 1 C14 0.01uF SMD 0805

28 1 C19 47uF/10V SMD Tantalum Capacitor

29 1 C22 470uF/16V Aluminum Capacitor


52

30 4 R7, R11, R21, R22 20 KΩ SMD 0805

31 4 R10, R13, R14, R15 100 KΩ SMD 0805, 1%, 1/16 W, 50 V

32 1 R16 50 Ω SMD 0805, 1%, 1/16 W, 50 V

33 2 R17, R82 0 Ω SMD 0805, 1%, 1/16 W, 50 V

34 7 R18, R23, R24, R25, R40, R45, R46 10 KΩ SMD 0805

35 12 R19, R26, R28, R31, R32, R33, R34, R35, R36, R38, R39, R42 1 KΩ SMD 0805

36 2 R20, R41 100 Ω SMD 0805

37 2 R27, R43 0 Ω SMD 0805

38 1 R29 10 KΩ SMD 0805, 1%, 1/16 W, 50 V

39 1 R30 5.1 KΩ SMD 0805, 1%, 1/16 W, 50 V

40 1 R37 5.1 KΩ SMD 0805


53

Table 7-2 Bill of Analog Board Materials

Item Quantity Reference Value Comments

1 1 U1 MPS-3117-006G Pressure Sensor, 6-SOP

2 2 U2, U4 LM358 8-SOP

3 1 U3 LM311 8-SOP

4 1 Q1 9012 SMD SOT-23

5 2 J1, J2 CON2 2-SIP

6 1 J3 CON6 6-SIP

7 1 J4 CON3 3-SIP


9 10 C2, C3, C4, C5, C7, C8, C9, C10, C11, C12 0.1uF SMD 0805

10 2 R1, R2 4.7 KΩ SMD 0805

11 2 R3, R23 100 Ω SMD 0805, 1%, 1/16 W, 50 V

12 1 R4 1.2 KΩ SMD 0805, 1%, 1/16 W, 50 V

13 1 R5 0 KΩ SMD 0805, 1%, 1/16 W, 50 V

14 5 R6, R8, R13, R17, R35 1 MΩ SMD 0805, 1%, 1/16 W, 50 V

15 2 R7, R16 1.3 MΩ SMD 0805, 1%, 1/16 W, 50 V

16 2 R9, R10 200 KΩ SMD 0805, 1%, 1/16 W, 50 V

17 3 R11, R12, R29 30 KΩ SMD 0805, 1%, 1/16 W, 50 V

18 5 R14, R15, R25, R27, R30 1 KΩ SMD 0805, 1%, 1/16 W, 50 V

19 1 R18 1.5 MΩ SMD 0805, 1%, 1/16 W, 50 V

20 1 R19 360 KΩ SMD 0805, 1%, 1/16 W, 50 V

21 1 R20 2.4 KΩ SMD 0805, 1%, 1/16 W, 50 V

22 1 R21 182 KΩ SMD 0805, 1%, 1/16 W, 50 V

23 1 R22 100 KΩ SMD 0805, 1%, 1/16 W, 50 V

24 1 R24 50 KΩ BOURNS3362 Single-Turn Cermet Trimmers

25 1 R26 10 KΩ SMD 0805

26 2 R28, R32 10 KΩ SMD 0805, 1%, 1/16 W, 50 V

27 1 R31 49.9 KΩ SMD 0805, 1%, 1/16 W, 50 V

28 1 R33 5.1 MΩ SMD 0805, 1%, 1/16 W, 50 V

29 1 R34 10 MΩ SMD 0805, 1%, 1/16 W, 50 V


54

8 APPENDIX 2: SOURCE CODE

For details on the source code, refer to the Arm_Blood_Pressure_Monitor_S3P8245_V1.2.rar.

s3p8245 arm blood pressure monitor an rev0.00 · pdf file1.4 process of blood measurement in...

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