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APPLICATION NOTE

S3F84A5 Electric Bike Controller System

January 2010

Revision 1.10

Confidential Proprietary of Samsung Electronics Co., Ltd

Copyright © 2010 Samsung Electronics, Inc. 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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S3F84A5 Electric Bike Controller System Application Note, Revision 1.10

Copyright 2010 Samsung Electronics Co., Ltd.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electric or mechanical, by photocopying, recording, or otherwise, without the prior written consent of Samsung Electronics.

Samsung Electronics Co., Ltd. San #24 Nongseo-Dong, Giheung-Gu Yongin-City, Gyeonggi-Do, Korea 446-711

TEL : (82)-(031)-209-4356 FAX : (82)-(031)-209-3262

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

Printed in the Republic of Korea

Revision History

Revision No. Date Description Author(s)

0 - Initial draft

1.10 Jan. 20, 2010

Table of Contents

1 Electric Bike Controller System...................................................................9

2 Overview of Electric Bikes .........................................................................10

2.1 General System Block Diagram of e-bike..................................................................................................11 2.2 Overview of 3-Phase BLDC Motor.............................................................................................................11

2.2.1 BLDC Motor ........................................................................................................................................11 2.2.2 Stator ..................................................................................................................................................12 2.2.3 Rotor ...................................................................................................................................................12

2.3 Key Electrical Characteristics of e-bike Controller.....................................................................................13

3 Overview of S3F84A5 Microcontroller.......................................................14

4 Reference Design with S3F84A5................................................................16

4.1 System diagram of S3F84A5.....................................................................................................................16 4.2 Main Blocks in Reference Design..............................................................................................................18

4.2.1 Power Supply......................................................................................................................................18 4.2.2 Battery Voltage Detect........................................................................................................................18 4.2.3 Handlebar Voltage Detect ..................................................................................................................19 4.2.4 System Feedback Current Detect ......................................................................................................19 4.2.5 Over-current Protection ......................................................................................................................20 4.2.6 Brake Mechanism...............................................................................................................................21 4.2.7 Hall Sensor Position Detect................................................................................................................21 4.2.8 Power MOSFET and Driver................................................................................................................22 4.2.9 Other Functions ..................................................................................................................................26 4.2.10 Debugger Socket ..............................................................................................................................27 4.2.11 Program Interface.............................................................................................................................27

5 Software Description ..................................................................................28

5.1 Overview of the Software Used in e-bike Controller Reference Design....................................................28 5.2 Software Flow ............................................................................................................................................30

5.2.1 Main flow.............................................................................................................................................30 5.2.2 Subroutine flow...................................................................................................................................31

5.2.2.1 Battery Voltage Detect ..............................................................................................................31 5.2.2.2 Handlebar Voltage Detect .........................................................................................................32 5.2.2.3 System Feedback Current Detect.............................................................................................33 5.2.2.4 Under-voltage Protection ..........................................................................................................34 5.2.2.5 Over-current Protection.............................................................................................................35 5.2.2.6 Brake Mechanism .....................................................................................................................36 5.2.2.7 Constant Speed Control............................................................................................................37 5.2.2.8 Speed Loop Control ..................................................................................................................38 5.2.2.9 Current Loop Control.................................................................................................................39

5.2.3 PWM Control ......................................................................................................................................40 5.2.3.1 A. Start PWM ............................................................................................................................40 5.2.3.2 B. Initialization PWM .................................................................................................................41 5.2.3.3 C. Resume PWM ......................................................................................................................41 5.2.3.4 D. Stop PWM ............................................................................................................................42

5.2.4 Interrupt Service Routine....................................................................................................................42 5.2.4.1 A. External INT0 (Over-current Protection) ISR........................................................................42 5.2.4.2 B. External INT1 (Brake Mechanism) ISR ................................................................................43 5.2.4.3 C. External INT2 ~ 4 (Phase A/B/C Change) ISR.....................................................................44 5.2.4.4 D. Timer 0 Match Interrupt (Speed Counting) ISR....................................................................45

6 Appendix I: Schematic Diagram of reference design ..............................46

7 Appendix II: Demo System .........................................................................47

8 Appendix III: Source Code..........................................................................51

List of Figures

Figure Title Page Number Number Figure 2-1 Bicycle Style and Scooter Style Electric Bikes ...................................................................................10 Figure 2-2 General System Diagram of e-bike.....................................................................................................11 Figure 2-3 BLDC Motor Mechanical Structure .....................................................................................................12 Figure 3-1 S3F84A5 Pin Assignment (28-SOP/SSOP Package) ........................................................................15 Figure 3-2 S3F84A5 Pin Assignment (32-ELP) ...................................................................................................15 Figure 4-1 E-bike Controller System Diagram .......................................................................................................16 Figure 4-2 Power Supply......................................................................................................................................18 Figure 4-3 Battery Voltage Detect Circuit.............................................................................................................19 Figure 4-4 Handlebar Voltage Detect and Speed Limited Circuit ........................................................................19 Figure 4-5 System Feedback Current Detect Circuit ...........................................................................................20 Figure 4-6 System Over-current Protection Circuit ..............................................................................................20 Figure 4-7 Brake Mechanism Waveform (P1.1)...................................................................................................21 Figure 4-8 Brake mechanism Circuit....................................................................................................................21 Figure 4-9 Hall Sensor Position Detect and Velocity Meter Circuit......................................................................21 Figure 4-10 Hall Sensor Position Waveform Diagram .........................................................................................22 Figure 4-11 Power MOSFET and Integrated Driver Circuit .................................................................................25 Figure 4-12 Other Function Input Selection Circuit ..............................................................................................26 Figure 4-13 On-board Debugger Socket..............................................................................................................27 Figure 4-14 Program Interface .............................................................................................................................27 Figure 5-1 Main Flow............................................................................................................................................30 Figure 5-2 Battery Voltage Detect Subroutine Flow.............................................................................................31 Figure 5-3 Handlebar Voltage Detect Subroutine Flow .......................................................................................32 Figure 5-4 System Feedback Current Detect Subroutine Flow ...........................................................................33 Figure 5-5 Battery Under-voltage Protection Subroutine Flow ............................................................................34 Figure 5-6 System Over-current Protection Subroutine Flow ..............................................................................35 Figure 5-7 Brake Mechanism Subroutine Flow....................................................................................................36 Figure 5-8 Constant Speed Control Subroutine Flow ..........................................................................................37 Figure 5-9 Speed Loop Control Subroutine Flow.................................................................................................38 Figure 5-10 Current Loop Control Subroutine Flow .............................................................................................39 Figure 5-11 Start PWM Control Subroutine Flow.................................................................................................40 Figure 5-12 Initialization PWM Control Subroutine Flow .....................................................................................41 Figure 5-13 Resume PWM Control Subroutine Flow...........................................................................................41 Figure 5-14 Stop PWM Control Subroutine Flow.................................................................................................42 Figure 5-15 External INT0 (Over-current Protection) Interrupt Service Routine Flow .........................................42 Figure 5-16 External INT1 (Brake Mechanism) Interrupt Service Routine Flow..................................................43 Figure 5-17 External INT2 ~ 4 (Phase A/B/C Change) Interrupt Service Routine Flow ......................................44 Figure 5-18 Timer 0 Match (Speed Counting) Interrupt Service Routine Flow....................................................45 Figure 6-1 Schematic Diagram of E-bike Controller Reference Design ..............................................................46

Figure 7-1 E-bike Controller Reference Design Demo System ...........................................................................47 Figure 7-2 E-bike Controller Reference Design Control Board............................................................................48 Figure 7-3 E-bike Controller Hall Sensor Position Real Waveform Diagram (Full Speed) ..................................49 Figure 7-4 E-bike Controller 3-Phases Real Waveform Diagram (Full Speed) ...................................................49 Figure 7-5 E-bike Controller Hall Sensor Position Real Waveform Diagram (Low Speed) .................................50 Figure 7-6 E-bike Controller 3-Phases Real Waveform Diagram (Low Speed)...................................................50

List of Tables

Table Title Page Number Number Table 4-1 The Pins Assignment of E-bike Controller Solution based on S3F84A5.............................................17 Table 4-2 Sequence of Forward Rotating ............................................................................................................22 Table 4-3 Sequence of Reverse Rotating ............................................................................................................23 Table 4-4 P2PWMOUT Register Configuration during Non-synchronous Rectification Mode ............................23 Table 4-5 P2PWMOUT Register Configuration in Non-synchronous Rectification Mode ...................................24 Table 4-6 Other Functions in E-bike Reference Design ......................................................................................26 Table 5-1 Routine lists of e-bike Controller Reference Design Software.............................................................28

S3F84A5_APPLICATION NOTE_REV1.10 1 ELECTRIC BIKE CONTROLLER SYSTEM

Samsung Confidential 9

1 ELECTRIC BIKE CONTROLLER SYSTEM

This chapter describes Samsung’s S3F84A5 microcontroller that is designed for electric bike (e-bike) controller system, including its hardware design and software process. It also provides the test system and signal output waveforms for reference.

Electric bike is a kind of green, energy-saving means of transport in China. It includes several components such as frame, host motor, controller, and battery. The controller in e-bikes is composed of current-limiting circuit, Hall location detection circuit, MOSFET full bridge circuit, and microcontroller.

S3F84A5_APPLICATION NOTE_REV1.10 2 OVERVIEW OF ELECTRIC BIKES

2 OVERVIEW OF ELECTRIC BIKES

Electric bikes are light electric vehicles (LEVs) used for convenient local transportation in China. Designed for one-person capacity, these pedal-driven e-bikes include two wheels – one at the front and other at the rear – attached by a frame. These e-bikes are available in two variants, namely, bicycle style and scooter style. The bicycle style e-bikes are supplemented by electrical power from a storage battery. On the other hand, the low-speed scooter style e-bikes are propelled by electricity. Figure 2-1 shows a typical bicycle-style and scooter-style e-bike.

Figure 2-1 Bicycle Style and Scooter Style Electric Bikes

The main components of e-bike include hub motor, controller, and valve-regulated lead-acid (VRLA) battery. Typically, bicycle-style e-bikes have 36V battery and 180-250W motors. On the other hand, scooter-style e-bikes have 48V batteries and 350-500W motors.

NOTE: e-bikes should not exceed 20km/hr limit (based on a regulation in China), but many e-bikes (especially scooter-style) can travel at speeds in excess of this limit. Some can even go up to 40km/hr.



2.1 GENERAL SYSTEM BLOCK DIAGRAM OF E-BIKE

Figure 2-2 shows the general system block diagram of e-bike controller. The e-bike controller consists of current limit circuit, Hall rotor position detection circuit, power MOSFET full bridge circuit, and microcontroller.

Power MOSFETBridge Driver BLDC

Motor

PowerMOSFET

Hall Rotor SensorPosition Detection

Microcontroller

CurrentLimited Circuit

Figure 2-2 General System Diagram of e-bike

The microcontroller processes feedback from the sensor to control the Power MOSFET driver that supplies the 3-phase Brushless Direct Current (BLDC) motor. At the same time, the speed of the BLDC motor is derived from the sensor signals and is used to provide velocity feedback for the closed speed loop.

2.2 OVERVIEW OF 3-PHASE BLDC MOTOR

2.2.1 BLDC MOTOR

Brushless Direct Current (BLDC) motor is a type of synchronous motor, where magnetic fields generated by both stator and rotate have the same frequency.

The BLDC motor has a longer life since no brushes are needed. Apart from that, it has a high starting torque, high no-load speed and small energy losses.

BLDC motor can be configured in 1-phase, 2-phase and 3-phase. 3-phase motors are the most popular among all the configurations and are widely used in e-bikes.

The structure of BLDC motor is divided into two parts:

Moving part called the rotor, represented by permanent magnet

Fixed part called the stator, represented by phase windings of magnetic circuit



2.2.2 STATOR

The stator of a BLDC motor consists of stacked steel laminations with windings placed in the slots that are axially cut along the inner periphery. Traditionally, the stator resembles to an induction motor; however, the windings are distributed in a different manner.

Most BLDC motors have three stator windings connected in star fashion. Each of these windings is constructed with numerous coils that are interconnected to form a winding. One or more coils are placed in the slots and they are interconnected to make a winding. Each of these windings is distributed over the stator periphery to form an even number of poles.

2.2.3 ROTOR

The rotor is made of permanent magnet and can vary from two to eight pole pairs with alternate North (N) and South (S) poles.

Figure 2-3 BLDC Motor Mechanical Structure

Unlike a brushed DC motor, BLDC motor can be controlled electronically. To rotate the BLDC motor, the stator windings should be energized in a special sequence. It is important to know the rotor position in order to understand which winding will be energized next. Rotor position is sensed using Hall Effect sensors that are embedded in the stator.

Most BLDC motors have three Hall sensors embedded in the stator on the non-driving end of the motor.

Whenever the rotor magnetic poles pass near the Hall sensors, they generate a high or low signal, which indicates that N or S pole is passing near the sensors. Based on the combination of these Hall Sensor signals, the exact sequence of commutation can be determined.




2.3 KEY ELECTRICAL CHARACTERISTICS OF E-BIKE CONTROLLER

The key electrical characteristics of e-bike controller include:

Rated Voltage: 24V/36V/48V DC (Lead Acid Battery)

Rated Power: 240W ~ 500W

Motor Speed: 0 ~ 40 km/h variable-speed by handlebar

Speed Restriction: Maximum 20km/h (by Jumper)

Battery Under-voltage Protection: 31.5 0.5V/41.5 0.5V

When the voltage of 36V battery drops to 31.5V, or when the voltage of 48V battery drops to 41.5V, motor should be disconnected from the power supply in order to increase the battery life. After that, the motor will stop until the power supply voltage is above 33V for +36V battery or 44V for +48V battery. Note that the recover voltage level is higher than that of under-voltage protection.

System Over-current Protection: 15 1A

When the feedback current going through the Power MOSFETs exceeds 15A, the motor should be shut down immediately. Restart happens when the current recovers to its normal value.

1:1 Strengthener

While riding the e-bike, the motor should supply motor-driven power assistance at the same speed to make the ride easier.

Auto-cruising

When the handlebar is held at a certain position for more than 8 seconds, the microcontroller will enter into auto-cruising mode. In this mode, e-bike will keep running at its current speed even if you let go of the handlebar. The Auto-cruising mode can be released if you turn the handlebar again or when the brake is applied.

Other functions of e-bike controller include three speed, guard key, self-check, and Electric-ABS.

S3F84A5_APPLICATION NOTE_REV1.10 3 OVERVIEW OF S3F84A5 MICROCONTROLLER


3 OVERVIEW OF S3F84A5 MICROCONTROLLER

The S3F84A5 single-chip CMOS microcontrollers are fabricated using the highly advanced CMOS process technology based on Samsung’s latest CPU architecture. It is ideal for use in a wide range of home applications and motor controller (especially for e-bike and other BLDC Motor applications).

The key features of S3F84A5 include:

SAM8 RC CPU core

400-byte general-purpose registers (RAM)

16K-byte full flash embedded ROM

Up to 10MHz main clock

Internal RC oscillator: 5% (typical) at full range of voltage and temperature

Four configurable I/O ports (total 24 pins)

17 interrupt sources with 17 vectors and 8 interrupt levels

One watchdog timer function (Basic Timer Overflow)

One 8-bit basic timer for oscillation stabilization

Two 8-bit timer/counter with time interval, PWM, and Capture mode (Timer B with interval and “8+2” bit PWM mode)

One 16-bit timer/counter with three operating modes: Interval timer, Capture, and PWM modes

10-bit resolution ADC with eight input channels, integrated sample and hold circuit, event trigger to start A/D converter conversion, and interrupt on ADC conversion complete.

8-bit PWM module, six output channels with two compare units, complementary or independent of output modes for each group, edge and center aligned waveform modes, programmable dead-time control for complementary mode, and three interrupt sources (one overflow and two match).

One asynchronous UART

Four low voltage reset (LVR) level: 2.3V/3.0V/3.9V

28-SOP package, 28-SSOP package, and 32-ELP package available

S3F84A5_APPLICATION NOTE_REV1.10 3 OVERVIEW OF S3F84A5 MICROCONTROLLER

VSS

(Vpp) TESTRxD/P0.0TxD/P0.1

nRESET/P0.2AVREF

INT0/ADC0/P1.0INT1/ADC1/P1.1

ADC2/P1.2ADC3/P1.3ADC4/P1.4ADC5/P1.5 P1.6/ADC6

P1.7/ADC7

123456789

1011121314 15

16

VDDP3.2/INT4 (SCLK)P3.1/INT3(SDAT)P3.0/INT2P2.7/T0OUT/PWM3AP2.6/T0CAP/PWM3BP2.5/TBOUTP2.4/T0CK/PWM2AP2.3/PWM2BP2.2/TACAPP2.1/TACK/PWM1AP2.0/TAOUT/PWM1B

282726252423222120191817

XOUT/P3.3XIN/P3.4

S3F84A5

(Top View)

28-SOP28-SSOP

Figure 3-1 S3F84A5 Pin Assignment (28-SOP/SSOP Package)

(Vp

p)T

ES

T

RxD

/P0.

0

1 2 3 4 5 6 7 8

(SD

AT

)IN

T3

/P3

.1

(SC

LK)I

NT

4/P

3.2

VD

D

VSS

Xo

ut/

P3

.3

Xin

/P3.

4

P1.1/ADC1/INT1

15

14

13

12

11

10

9 P0.1/TxD

P0.2/nRESET

AVREF

P1.0/ADC0/INT0

P1.2/ADC2

P1.3/ADC3

NC24

23

22 21 20

19

18

17

P1

.5/A

DC

5

P1.

6/A

DC

6

P1

.7/A

DC

7

P2

.0/T

AO

UT

/PW

M1B

P2

.1/T

AC

K/P

WM

1A

P2

.2/T

AC

AP

NC

P1

.4/A

DC

4

TBOUT/P2.5

PWM3B/T0CAP/P2.6

PWM3A/T0OUT/P2.7

INT2/P3.0

NC

NC

PWM2A/T0CK/P2.4

PWM2B/P2.3 25

26

27

28

29

30

31

32

16

S3F84A5

(Top View)

32-ELP

Figure 3-2 S3F84A5 Pin Assignment (32-ELP)


S3F84A5_APPLICATION NOTE_REV1.10 4 REFERENCE DESIGN WITH S3F84A5

4 REFERENCE DESIGN WITH S3F84A5

4.1 SYSTEM DIAGRAM OF S3F84A5


Figure 4-1 shows the e-bike Controller system diagram when S3F84A5 is used for BLDC motor control.

BLDC

Motor

PowerBridgePWM

PWM 3APWM 3BPWM 2APWM 2BPWM 1APWM 1B

Phase APhase BPhase C

AMP

HandlebarVol.

Battery Vol .

FeedbackCur.

Ext. INT Ref.

Over-current

CMP

Hall AHall BHall C

Three Speed

Guard Key

1:1 Strengthener

Constant Speed

Self-check

EABS

60o/120o

SystemStatus Disp.

I/O

Brake

CPU

OSC/RST LVR

S3F84A5

Optional

ROMTimer

ADC

RAM

I/O

Figure 4-1 E-bike Controller System Diagram

The e-bike controller system includes:

Three external interrupts are used for getting position information from Hall sensors while one is used for brake mechanism.

One timer is used for counting the Hall interrupts in a fixed time to get speed information.

Three ADC channels are used for detecting battery voltage, handlebar voltage, and system feedback current.

PWM output directly controls the power bridge. Different duty cycle results in different vehicle speeds.

Remaining I/O can be used as advanced function input pins or system status indicating pins.



Table 4-1 The Pins Assignment of E-bike Controller Solution based on S3F84A5

Pin No. Pin Name Pin Setting Function

1 VSS - Ground

2 XOUT/P3.3 Output @ XOUT Or Input @ P3.3

Ext. OSC output pin or Electrical ABS enable pin

3 XIN/P3.4 Input @ XIN Or Input @ P3.4

Ext. OSC output pin or Self-check enable pin

4 TEST - Test signal input pin

5 P0.0 Output Indicator (LED) for 1:1strengthener enable

6 P0.1 Output Indicator (LED) for Auto-cruise enable/disable. In other words, when you enable auto-cruise, the LED will be turned ON. The LED will be turned OFF when auto-cruise is disabled.

7 nRESET/P0.2 Output @ nRESET Or Input @ P0.2

Reset input Hall sensor 60/120 degree selection pin

8 AVREF - Reference voltage input of ADC

9 INT0/P1.0 Int. input (falling edge) System over-current protection pin

10 INT1/P1.1 Int. input (falling edge) Brake mechanism pin

11 ADC2/P1.2 ADC input System feedback current detection pin

12 ADC3/P1.3 ADC input Handlebar voltage detection pin

13 ADC4/P1.4 ADC input Battery voltage detection pin

14 P1.5 Input Auto-cruise enable pin

15 P1.6 Input Guard-key input pin

16 P1.7 Input Three speed button

17 PWM1B/P2.0 PWM / IO output Phase C low bridge control pin

18 PWM1A/P2.1 PWM / IO output Phase C high bridge control pin

19 TACAP/P2.2 Input (Capture) 1:1 strengthener input pin

20 PWM2B/P2.3 PWM / IO output Phase B low bridge control pin

21 PWM2A/P2.4 PWM / IO output Phase B high bridge control pin

22 TBOUT/P2.5 Output Self-check enable indicating LED

23 PWM3B/P2.0 PWM / IO output Phase A low bridge control pin

24 PWM3A/P2.1 PWM / IO output Phase A high bridge control pin

25 INT2/P3.0 Hall sensor C position detection pin

26 INT3/P3.1 Hall sensor B position detection pin

27 INT4/P3.2

Int. input (falling or rising edge changed at ISR)

Hall sensor A position detection pin

28 VDD - Power


4.2 MAIN BLOCKS IN REFERENCE DESIGN

The reference design can be divided into following main blocks: power supply, microcontroller, battery voltage detect, handlebar voltage detect, system feedback current detect, battery under-voltage protection, system over-current protection, brake mechanism, Hall sensor position detect, power MOSFET and driver.

4.2.1 POWER SUPPLY

There are three power levels in e-bike system. All are oriented from a +48V/+36V battery.

+48V/+36V can drive the power MOSFET directly.

+15V specifies the power supply of MOSFET driver ICs in power bridge.

+5V specifies the power supply of microcontroller and other devices.

S1 led (red) on the board indicates the power status.

+ C3

220uF/50V

VIN3

ADJ1

VOUT2

U1

LM317/CYL

INPUT1

OUTPUT3

GN

D2

7805

U2

7805

C7

104

D+1

J6

CON1

R2243 ohm

R14

330 ohm/2WR3330 ohm

S1LED

C8

104

+15V VDD

1

J5

CON1

R12.7 Kohm

+48V/+36V

+C1

47uF/50V

C6

104

+ C11

1000uF/65V

+ C24

100uF/50V

Figure 4-2 Power Supply

4.2.2 BATTERY VOLTAGE DETECT

Figure 4-3 shows the battery voltage detect circuit. The battery has two electrodes – positive and negative. In case of right polarity, diode D5 is turned on and it supplies the normal power. On the other hand, in case of wrong polarity, diode D5 is on the reverse voltage and it does not turn on. It can protect other devices in system including the MCU ADC input.

If ADC result is lower than a preset value, under voltage protection can be done. The battery in e-bike contains lead-acid. The voltage discharge cannot be too low; otherwise, it will cause permanent damage to the battery. ADC should detect this voltage during normal operation. If the battery voltage is less than a certain preset value, MCU will go into Under Voltage Protection mode.



D51N4001

R46

10 Kohm

R48

10 Kohm

R47

2 KohmC17

104

D+

P1.4/ADC4

Figure 4-3 Battery Voltage Detect Circuit

4.2.3 HANDLEBAR VOLTAGE DETECT

Jumper S4 is used for speed limitation. When S4 is on connected, R61 is connected in parallel with R59, which makes the ADC input voltage much lower than the time S4 is off.


P1.3/ADC3C22

104

C23

104

R61

20 Kohm

R60

1 Kohm

R592.49 Kohm

12

S4

CON2

123

S3

CON3

HL_VVDD

VDD

GND

Figure 4-4 Handlebar Voltage Detect and Speed Limited Circuit

4.2.4 SYSTEM FEEDBACK CURRENT DETECT

As shown in the figure, one LM358 op-amp is used for the measurement of system feedback current. Gain control resistors (R16, R17) guarantee the ADC input voltage within the range of 0 to +5V.



3

21

84

-

+

U9A

LM358

R17

1 Kohm

R16

10 Kohm

C10

102

P1.2/ADC2

R181 Kohm

Feedback CurrentVfb

VDD

Figure 4-5 System Feedback Current Detect Circuit

4.2.5 OVER-CURRENT PROTECTION

The controller can judge over-current using two kinds of “outside” conditions:

First condition: The feedback current abruptly rises up to an unexpected value. This could be caused by MOSFET short or motor rotation blockage.

Second condition: The current is above a preset safe value (usually 50A), which is set for the system safety.

The former condition is realized by an external comparator (see Figure 4-6). On the other hand, the latter condition is realized by feedback current detection.

5

67

84

-

+

U9B

LM358R7

1 Kohm

R610 Kohm

R4

10 Kohm

R51 Kohm

VDD

C9

104

VDD

P1.0/INT0

VDD

VfbFeedback Current

Figure 4-6 System Over-current Protection Circuit


4.2.6 BRAKE MECHANISM

In this reference design, brake mechanism can support both high level and low level brake signals. As shown in


Figure 4-7, whatever the brake signal is, P1.1 will have the following waveform.

No brake signal No brake signal

Brake

Figure 4-7 Brake Mechanism Waveform (P1.1)

R44

10 Kohm

VDD

R42

2 Kohm

1234

U18

CON4

Brake_Low

BK-L

Brake_High

R43

10 Kohm

VDD

D4

IN4148

C19 330 ohm

C18

104

BK-H

Q29013

Figure 4-8 Brake mechanism Circuit

4.2.7 HALL SENSOR POSITION DETECT

The synchronization between the rotor and rotating field requires knowledge of the rotor position. The BLDC motor used in this application has 3-hall sensors.

The hall sensor position detection circuit and velocity meter circuit is shown in Figure 4-9.

VDD

Q19013

R4149.9 Kohm

VDD

12

S2

CON2

H2GND

R4020 Kohm

VDD

R33 150 ohm

H2

R4910 Kohm

R50 330 ohm123456

U17

CON6

H3

R5110 Kohm

VMR5310 Kohm

R52 330 ohmR54 330 ohm

P3.2/INT4 H1P3.1/INT3P3.0/INT2

C12

104

C13

104

C14

104

Figure 4-9 Hall Sensor Position Detect and Velocity Meter Circuit


The output signal flow of sensors, which describes the electrical rotor position, is shown in


Figure 4-10.

Eight possible signal combinations can be used as three sensors’ output. Two of these combinations are not valid for position detection and are usually caused by an open or short sensor line. Other six combinations will be detected by external interrupts both at the rising and falling edge.

1800 360 540 720

1 Electrical Cycle 1 Electrical Cycle

Hall

Sensor A

Hall

Sensor B

Hall

Sensor C

1 2 3 4 5 6 1 2 3 4 5 6 1 ......

Figure 4-10 Hall Sensor Position Waveform Diagram

4.2.8 POWER MOSFET AND DRIVER

Table 4-2 Sequence of Forward Rotating

Hall Sensor Input Active MOSFET Phase Current Sequence #

A B C H-Bridge L-Bridge A B C

1 0 0 1 C B Off DC- DC+

2 1 0 1 A B DC+ DC- Off

3 1 0 0 A C DC+ Off Dc-

4 1 1 0 B C Off DC+ DC-

5 0 1 0 B A DC- Dc+ Off

6 0 1 1 C A DC- Off DC+



Table 4-3 Sequence of Reverse Rotating

Hall Sensor Input Active MOSFET Phase Current Sequence #

A B C H-Bridge L-Bridge A B C

1 0 0 1 B C Off DC+ DC-

2 0 1 1 A C DC+ Off DC-

3 0 1 0 A B DC+ DC- Off

4 1 1 0 C B Off DC- DC+

5 1 0 0 C A DC- Off DC+

6 1 0 1 B A DC- DC+ Off

The freewheeling function can be realized in two ways.

First is the non-synchronous rectification, where current is freewheeled by body-diode of the complementary MOSFET.

Second is synchronous rectification, where current is freewheeled directly by the complementary MOSFET.

In this reference design, non-synchronous rectification is implemented. Since the PWM module in S3F84A5 can realize dead time control, synchronous rectification can also be supported.

In non-synchronous rectification, there is no need to control the complementary MOSFET of the MOSFET driven by PWM signal. Thus, only two MOSFETs are in action at one time. The difference is one is driven by PWM signal for speed control, while the other is driven by full duty cycle PWM. (The effect is the same as a normal IO. It is just a trick for better synchronization between the active high and low bridge. Once the compare data is set for PWM module, all the PWM outputs have the same start point even if there is instruction delay when implemented by IOs).

Table 4-4 P2PWMOUT Register Configuration during Non-synchronous Rectification Mode

When the BLDC Motor is Forward Rotating

Hall Sensor Input P2PWMOUT Register Configuration Sequence #

A B C Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 HEX

1 0 0 1 0 0 x 0 1 x 1 0 2EH

2 1 0 1 1 0 x 0 1 x 0 0 ACH

3 1 0 0 1 0 x 0 0 x 0 1 A5H

4 1 1 0 0 0 x 1 0 x 0 1 35H

5 0 1 0 0 1 x 1 0 x 0 0 74H

6 0 1 1 0 1 x 0 0 x 1 0 66H



Table 4-5 P2PWMOUT Register Configuration in Non-synchronous Rectification Mode

When the BLDC Motor is Backward Rotating

Hall Sensor Input P2PWMOUT Register Configuration Sequence #

A B C Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 HEX

1 0 0 1 0 0 x 1 0 x 0 1 35H

2 0 1 1 1 0 x 0 0 x 0 1 A5H

3 0 1 0 1 0 x 0 1 x 0 0 ACH

4 1 1 0 0 0 x 0 1 x 1 0 2EH

5 1 0 0 0 1 x 0 0 x 1 0 66H

6 1 0 1 0 1 x 1 0 x 0 0 74H



1

J2

CON1

U375NF75

U475NF75

U

D+

U

R15

0.01 ohm

V

1

J3

CON1

P2.6/PWM3B

Vcc1

HIN2

LIN3

COM4

LO5Vs6HO7VB8

U10

IR2101

P2.7/PWM3A

D1

US1G

W

+15V

U575NF75

U675NF75

V

D+

P2.3/PWM2B

Vcc1

HIN2

LIN3

COM4

LO5Vs6HO7VB8

U11

IR2101

P2.4/PWM2A

D2

US1G

+15V

R10 33 ohm

R11 33 ohm

R21

330 ohmR22

330 ohm

+C2

3.3uF/25VPWM3A

PWM3B

U775NF75

U875NF75

D+

P2.0/PWM1B

Vcc1

HIN2

LIN3

COM4

LO5Vs6HO7VB8

U12

IR2101

P2.1/PWM1A

D3

US1G

PWM2A

+15V

R12 33 ohm

R13 33 ohm

R25

330 ohmR26

330 ohm

PWM2B

W

1

J1

CON1

R19

330 ohmR8 33 ohm

R9 33 ohm

PWM1A

+C4

3.3uF/25V

Vfb

R20

330 ohm

+C5

3.3uF/25V

PWM1B

Figure 4-11 Power MOSFET and Integrated Driver Circuit


4.2.9 OTHER FUNCTIONS

Table 4-6 Other Functions in E-bike Reference Design

No. E-bike Advanced Functions MCU I/O Note

1 Constant Speed Enable P1.5 Normal I/O

2 Guard Key P1.6 Normal I/O or IR receiving

3 Three Speed Button P1.7 Normal I/O or ADC input

4 1:1 Strengthener P2.2 Normal I/O or Capture input

5 Hall 60/120 degree Selection (Optional) P0.2 Shared with nRESET pin

6 E-ABS Enable (Optional) P3.3 Shared with XOUT pin

7 Self-check Enable (Optional) P3.4 Shared with XIN pin


VDD

SEL_CK

60_120

THR_SD

R39330 ohm

Hall 60/120 degree

G_KEY

R3810 Kohm

R2810 Kohm

R2310 Kohm

R27330 ohm

Three Speed

R3010 KohmR29330 ohm

Gard-Key


Constant Speed

P1.7

P1.6


EABS

CST_SD


Self-check

P1.5

XOUT/P3.3

XINT/P3.4

RST/P0.2

1_1ST P2.2R24330 ohm

1:1 Strengthener

E_ABS

E_ABS

60_1201_1ST

SEL_CK

THR_SDG_KEYCST_SD

1 23 45 67 89 10

11 1213 14

J4

CON14A

Figure 4-12 Other Function Input Selection Circuit


4.2.10 DEBUGGER SOCKET


Vss1

Xout/P3.32

Xin/P3.43

(Vpp)TEST4

RxD/P0.05

TxD/P0.16

nRESET/P0.27

AVref8

INT0/ADC0/P1.09

INT1/ADC1/P1.110

ADC2/P1.211

ADC3/P1.312

ADC4/P1.413

ADC5/P1.514

P1.6/ADC615P1.7/ADC716P2.0/TAOUT/PWM1B17P2.1/TACK/PWM1A18P2.2/TACAP19P2.3/PWM2B20P2.4/T0CK/PWM2A21P2.5/TBOUT22P2.6/T0CAP/PWM3B23P2.7/T0OUT/PWM3A24P3.0/INT225P3.1/INT3(SDAT)26P3.2/INT4(SCLK)27Vdd28

S3F84A5

28-SOP

U13

S3F84A5_28SOP

XOUT/P3.3GND

VPPXINT/P3.4

P0.0P0.1RST/P0.2AVREFP1.0/INT0P1.1/INT1P1.2/ADC2P1.3/ADC3P1.4/ADC4P1.5 P1.6

P1.7P2.0/PWM1BP2.1/PWM1AP2.2P2.3/PWM2BP2.4/PWM2AP2.5P2.6/PWM3BP2.7/PWM3AP3.0/INT2P3.1/INT3P3.2/INT4VDD

Figure 4-13 On-board Debugger Socket

4.2.11 PROGRAM INTERFACE

P3.1/INT3P3.2/INT4VDDGNDVPP

123456

U14

CON6

RST/P0.2

Figure 4-14 Program Interface

S3F84A5_APPLICATION NOTE_REV1.10 5 SOFTWARE DESCRIPTION


5 SOFTWARE DESCRIPTION

5.1 OVERVIEW OF THE SOFTWARE USED IN E-BIKE CONTROLLER REFERENCE DESIGN

This section describes the software used in the e-bike controller reference design. The software is written in C language.

The software includes five parts, namely, head-files, variable definition, main, subroutine, and interrupt service subroutine. The source code is included in the Table 5-1.

Table 5-1 Routine lists of e-bike Controller Reference Design Software

No. Routine Name Description Note

1 Main(void) Main loop. Main routine

2 MCU_INIT(void) System registers and I/O initialization.

3 RAM_INIT(void) RAM initialization.

4 VARIABLE_INIT(void) System variables (buffers and flags) initialization.

5 BATVOL_DETECT(void) Battery voltage detection.

6 HANDVOL_DETECT(void) Handlebar voltage detection.

7 SYSCUR_DETECT(void) System feedback current detection.

8 BRAKE_PROTECT(void) Brake mechanism.

9 UNDERVOL_PROTECT(void) Battery under-voltage protection.

10 OVERCURRENT_PROTECT(void) System over-current protection.

11 SPEED_LOOP(void) Speed loop control.

12 CURRENT_LOOP(void) Current loop control.

13 START_PWM(void) Start PWM output by current motor position

14 INIT_PWM(void) PWM output initialization.

15 RESUME_PWM(void) Resume PWM output.

16 STOP_PWM(void) Stop PWM output.

17 DELAY_MS(unsigned int nms) Delay in microseconds.

Subroutine

18 INT0_ISR(void) Over-current interrupt protection.

19 INT1_ISR(void) Brake interrupt service.

20 INT2_ISR(void) Hall sensor A interrupt service.

21 INT3_ISR(void) Hall sensor B interrupt service.

22 INT4_ISR(void) Hall sensor C interrupt service.

Interrupt Service Subroutine



No. Routine Name Description Note

23 T0_MAC_ISR(void) Timer 0 match interrupt service.

24 ADC_END_ISR(void) ADC conversion complete interrupt service.


5.2 SOFTWARE FLOW

5.2.1 MAIN FLOW St

art

Init

ializ

e I/

O P

ort

Reg

iste

rs

Cle

ar B

asic

Tim

er

Cou

nter

& D

ivid

er

Init

iali

ze S

yste

m R

eg.s

(I

MR

, IPR

, BT

CO

N,

CL

KC

ON

, SPL

)

Init

ializ

e U

ser

Var

iabl

e

Dis

able

Glo

bal I

nter

rupt

Con

figu

re T

imer

0

Ope

ratio

n M

ode

(fxx

/8,

inte

rval

0.0

5s, e

nabl

e m

atch

int.)

Del

ay 1

00 m

icro

seco

nd

Ena

ble

Wat

ch-d

og

Cal

l Bat

tery

Vol

tage

D

etec

t

Bat

tery

U

nder

-vol

tage

?

Syst

em

Ove

r-cu

rren

t ?

Bra

ke ?

Cal

l Sys

tem

Cur

rent

D

etec

t

Syst

em C

urre

nt

is N

orm

al ?

Cal

l Han

dleb

ar V

olta

ge

Det

ect

Cal

cula

te P

WM

Dut

y

Cal

cula

ted

Val

ue >

Cur

rent

V

alue

?

Cal

l Han

dleb

ar V

olta

ge

Det

ect

Cal

cula

te U

ser-

set S

peed

Use

r-se

t Spe

ed>

C

urre

nt S

peed

?

STO

P P

WM

Del

ay 5

0 m

s

STO

P P

WM

Del

ay 5

0 m

s

Dec

reas

e PW

M D

uty

Cyc

le

Del

ay 5

0 m

s

Dec

reas

e PW

M D

uty

Cyc

le

Dec

reas

e PW

M D

uty

Cyc

le

Incr

ease

PW

M D

uty

Cyc

le

Incr

ease

Spe

ed

Dec

reas

e Sp

eed

Ext

. IN

T2

(Pha

se A

) IS

RE

xt. I

NT

4 (P

hase

C)

ISR

Ext

. IN

T3

(Pha

se B

) IS

R

Spe

ed C

ount

ing

Und

er-V

olta

ge

Pro

tect

ion

Ove

r-cu

rren

t P

rote

ctio

n Bra

ke

Pro

tect

ion

Cu

rren

t L

oop

Spe

ed L

oop

Ena

ble

Glo

bal I

nter

rupt

Init

ializ

atio

n

Y Y Y

N N N

Y

N N

Y

N

Y

Figure 5-1 Main Flow

NOTE: In Figure 5-1, functions are simplified. Therefore, they may not be the same as what is described in the subroutine flow.



5.2.2 SUBROUTINE FLOW

5.2.2.1 Battery Voltage Detect

Start

Init. R0, R1(Sum of Bat. Voltage)

nBatVol = (R0,R1) /4

ADC4 Conv. Complete?(EOC==1?)

Set Under-voltage Flag

Add ADDATAH value to R0,R1

(Sum of Bat. Voltage)

Clr Under-voltage Flag

End

N

Y

NSample Time ==4 ?

N

Y

Init. R2 ( ADC Sample Time )

nBatVol > LowBatVol ?

(31.5V @ Vbat=36V)

nBatVol < NorBatVol ?

(33V @ Vbat=36V)

Start ADC4 Conversion

Y

Y

N

Configure ADC4 Operation Mode

Figure 5-2 Battery Voltage Detect Subroutine Flow



5.2.2.2 Handlebar Voltage Detect

Start

Init. R0, R1(Sum of Handlebar

Voltage)

nHandVol = (R0,R1) /4

ADC3 Conv. Complete?(EOC==1?)

Clear Handlebar ON Flag

Add ADDATAH value to R0,R1

(Sum of Handlebar Voltage)

End

N

Y

NSample Time ==4 ?

N

Y


nHandVol < Handlebar OFF

Vol. (1.05V) Start ADC3 Conversion

Y

Y

N

Configure ADC3 Operation Mode

nHandVol < Handlebar ON

Vol. (1.1V)

Handlebar is ON last time?

Set Handlebar ON Flag

nHandVol < Max. Handlebar Vol Value (4.5)?

Load Max. Handlebar Vol. Value to nHandVol

Load Init. Value to Port 2 Register

Load Init. Value to P2PWMOUT Register(Disable PWM Output)

Clear Phase Change Enable Flag

Call Resume PWM

Set Phase Change Enable Flag

N

Y

Brake is released ?

Y

N

Y

N

Figure 5-3 Handlebar Voltage Detect Subroutine Flow



5.2.2.3 System Feedback Current Detect

Start

Init. R0,R1(Sum of System Current)

ADC2 Conv. Complete?

(nADCConvEndFlag != 0 ?)

Add ADDATAH value to batvol_sum

N

Y

NSample Time ==4 ?


Y

Conf. ADC2 Oper.Mode (PWM A group match

int. trigger)

Enable PWM A Group Match Interrupt

Clear nADCConvEndFlag

(ADC Conv. End Flag)

nSysCur = (R0, R1) /4

Load Init. Value to Port 2

Clr Over-current Flag

End

N

YnSysCur < Over-current ?

(16A)

Disable PWM Output

Stop PWM Counter

Clear Phase Change Enable Flag, Handlebar

ON Flag

Set Over-current Flag

Disable PWM A Group Match InterruptPWM Counter is

running ?Start ADC2 Conversion

Figure 5-4 System Feedback Current Detect Subroutine Flow



5.2.2.4 Under-voltage Protection

Start


End

CallBattery Voltage Detect

Battery Under-voltage ?

CallStop PWM

Clear Basic Timer Counter & Divider

Delay 50 microsecond

CallBattery Voltage Detect

Battery Under-voltage ?

CallHandlebar Voltage

Detect

Handlebar Voltage is ON ?

CallResume PWM


N

Y

Y

N

N

Y

Optional : those codes are included in Handlebar Voltage Detection subroutine


Delay 1 second

Figure 5-5 Battery Under-voltage Protection Subroutine Flow



5.2.2.5 Over-current Protection

Start


End

System Over-current ?

CallStop PWM



CallSystem Current Detect

System Current > Limited

Current ? (10A)


Detect


CallResume PWM


N

Y

Y

N

N

Y

Ext. Over-current

Protection P1.0 keep LOW ?

N

Y

Clear System Over-current Flag


Optional : this code is included in System Current Detection subroutine

Optional : those codes are included in Handlebar Voltage Detection subroutine

Delay 2 seconds

Figure 5-6 System Over-current Protection Subroutine Flow



5.2.2.6 Brake Mechanism

Start


End

System Over-current ?

CallStop PWM



CallSystem Current Detect

System Current > Limited

Current ? (10A)


Detect


CallResume PWM


N

Y

Y

N

N

Y

Ext. Over-current

Protection P1.0 keep LOW ?

N

Y

Clear System Over-current Flag

Figure 5-7 Brake Mechanism Subroutine Flow



5.2.2.7 Constant Speed Control

Start

Load Min. Duty Cycle Value (33H) to R3

End

N

Load User-set Constant Speed Value to R7

Decrease R3 by One PWM Duty Step

Y

Load Current PWM Duty Value to R3

R7 (User-set Speed) >=

Current Speed ?

R3 > 33H ?(20% Duty

Cycle)

R7 (User-set Speed) ==

Current Speed ?

R3 < 252 ?

Load Max. Duty Cycle Value (0FFH) to R3

Add One PWM Duty Step to R3

Load R3 to Current PWM Duty Value

Calculate PWM B Group Duty Cycle Value

with 2us dead-time

Update PWM A&B Group Compare Data

Registers

N

Y

Y

N

N

Y

Figure 5-8 Constant Speed Control Subroutine Flow



5.2.2.8 Speed Loop Control

Start

Load Handlebar Voltage Value to R8, R9

End

Load Max. Speed (Limited) Value to User-

set Constant Speed

Y

Call Handlebar Voltage Detect

Handlebar is ON ?

Current Speed < Max. Speed (Limited)?

Call Constant Speed Control

Y

N

N

Current Speed > Min. Speed?

Load Min. Speed Value to User-set Constant

Speed

Calculate User-set Speed Value = handlebar vol. *

0.794 – 10.68

User-set Speed < Current Speed ?

User-set Speed < 80% * Max.

Speed ?

Current Speed > 60% * Max.

Speed ?

Load Quick Value (9) to PWM Duty Step Value

User-set Speed > 30% * Max.

Speed ?

Current Speed < 50% * Max.

Speed ?

Load Nor. Value (2) to PWM Duty Step Value

Load Nor. Value (2) to PWM Duty Step Value

Y

Y

N

N

N

N

Y

Y

N

N

Y

Y

Speed Limited (Optional)

Figure 5-9 Speed Loop Control Subroutine Flow



5.2.2.9 Current Loop Control

Start

Load Handlebar Voltage Value to R8, R9

End

Call System Current Detect

System is Over-current ?

System Current <12A (Limited)

Load R3 to Current PWM Duty

Y

N

Handlebar is ON ?

Calculate PWM Duty Value = handlebar vol. *

1.17 – 8.79

Current PWM Duty Value >= Calculate PWM

Duty Value?

Current PWM Duty Value <

252 ?

Load Max. PWM Duty Value (0FFH) to R3

Add One PWM Duty Step to R3

N

Y

YCall Handlebar Voltage

Detect


Current PWM Duty Value == Calculate PWM

Duty Value?

Decrease R3 with One PWM Duty Step

R3 >= 33 ?

Load Min. PWM Duty Value (33H) to R3

Calculate PWM B Group Duty with 2us

dead-time

Update PWM A&B Group Compare Date

Registers


Y

N

N

Y

N

N

Y

Y

N

Figure 5-10 Current Loop Control Subroutine Flow



5.2.3 PWM CONTROL

5.2.3.1 A. Start PWM

Start PWMStart

Disable PWM Interrupt


Calculate PWM B Group Duty Value with

2us dead-time

Update PWM A&B Group Compare Date

Registers

Configure PWM Operation Mode (center-aligned, fxx/1, A Non-inverted, B Inverted)

Read P3 (Hall Sensor Position

Information )

Look up from Motor Position Table

Update Port 2 Value


Update P2PWMOUT Value

Start PWMEnd

Figure 5-11 Start PWM Control Subroutine Flow



5.2.3.2 B. Initialization PWM

Initialize PWMStart

Load init. value (20%) to Current PWM Duty

Init. Port 2 Value

Init. P2PWMOUT Value(Disable PWM Output)

Call Start PWM

Initialize PWMEnd

Figure 5-12 Initialization PWM Control Subroutine Flow

5.2.3.3 C. Resume PWM

N

Y

N

Y

Resume PWMStart

Load Current Speed Value to R10,R11

Current Speed =< 10% * Max.

Speed ?

Current Speed >= 90% * Max.

Speed ?

nPWMDuty = (R10,R11) * 0.66

Load 33H (20%) to Current PWM Duty

Value

Load 0CCH (80%) to Current PWM Duty

Value

Call Start PWM

Resume PWMEnd

Figure 5-13 Resume PWM Control Subroutine Flow



5.2.3.4 D. Stop PWM

Stop PWMStart



Stop PWM Counter

Stop PWMEnd

Figure 5-14 Stop PWM Control Subroutine Flow

5.2.4 INTERRUPT SERVICE ROUTINE

5.2.4.1 A. External INT0 (Over-current Protection) ISR

Ext. INT0 ISRStart



Stop PWM Counter


Set System Over-current Flag

Ext. INT0 ISRReturn

Clear Ext. INT0 Pending Bit

Figure 5-15 External INT0 (Over-current Protection) Interrupt Service Routine Flow



5.2.4.2 B. External INT1 (Brake Mechanism) ISR

Ext. INT1 ISRStart

Clear Ext. INT1 Pending Bit

Delay 0.8 micro-sencond

P1.1(Brake) keep LOW ?

Set Brake Flag

Ext. INT1 ISRReturn

Y

N

Figure 5-16 External INT1 (Brake Mechanism) Interrupt Service Routine Flow



5.2.4.3 C. External INT2 ~ 4 (Phase A/B/C Change) ISR

Ext. INTx (x=2,3,4) ISRStart

Clear Ext. INTx Pending Bit (x=2,3,4)

Disable IRQ6 (Ext. INT2 ~ INT4)

Phase Change Enable ?

Read P3 (Hall Sensor Position

Information )


Update Port 2 Value


Update P2PWMOUT Value

Enable IRQ6 (Ext. INT2 ~ INT4)

Update Speed Counter

Re-configure P3CONL to change INT edge

(Falling/Rising)

Clear Ext. INTx Pending Bit (x=2,3,4)

Ext. INTx (x=2,3,4) ISR

Return

N

Y

Figure 5-17 External INT2 ~ 4 (Phase A/B/C Change) Interrupt Service Routine Flow



5.2.4.4 D. Timer 0 Match Interrupt (Speed Counting) ISR

Timer 0 Match ISRStart

Timer 0 Match ISRReturn

Clear Timer 0 Match Interrupt Pending Bit

Clear Timer Piece Counter

Y

Update Timer Piece Counter

Timer Piece Counter < 4 ?(0.2 second)

Load Speed Counter Value to Current Speed

Value

Clear Speed Counter

N

Figure 5-18 Timer 0 Match (Speed Counting) Interrupt Service Routine Flow


S3F84A5_APPLICATION NOTE_REV1.10 6 APPENDIX I: SCHEMATIC DIAGRAM OF REFERENCE DESIGN

6 APPENDIX I: SCHEMATIC DIAGRAM OF REFERENCE DESIGN

Figure 6-1 Schematic Diagram of E-bike Controller Reference Design

Double click to open


Figure 6-1 in Adobe Reader.

S3F84A5_APPLICATION NOTE_REV1.10 7 APPENDIX II: DEMO SYSTEM

7 APPENDIX II: DEMO SYSTEM

Target Board

BLDC MotorControl Board

Power Supply


Brake Handlebar

Figure 7-1 E-bike Controller Reference Design Demo System

+24V DC power is supplied to the control board.

Target board is used to simulate and debug software.

Control board contains MCU, detection circuits (battery voltage, handlebar, feedback current, and hall sensor position), protection circuits (battery under-voltage and over-current), brake mechanism, power MOSFET, and driver. BLDC motor is a 3-phase +24V DC brushless motor.

Handlebar is used to control motor speed while brake is used to decrease speed and stop the motor.

Figure 7-1 and Figure 7-2 show the demo system. Figure 7-2, Figure 7-3, Figure 7-4, and Figure 7-5 show the hall sensor positions and 3-phase waveform when motor is operating at full speed and low speed.


Figure 7-2 E-bike Controller Reference Design Control Board



Figure 7-3 E-bike Controller Hall Sensor Position Real Waveform Diagram (Full Speed)

Figure 7-4 E-bike Controller 3-Phases Real Waveform Diagram (Full Speed)



Figure 7-5 E-bike Controller Hall Sensor Position Real Waveform Diagram (Low Speed)

Figure 7-6 E-bike Controller 3-Phases Real Waveform Diagram (Low Speed)


S3F84A5_APPLICATION NOTE_REV1.10 8 APPENDIX III: SOURCE CODE

8 APPENDIX III: SOURCE CODE

Appendix III SW.doc


January 2010 Revision 1 - Samsung US · PDF fileThe information in this publication has been...

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Transcript of January 2010 Revision 1 - Samsung US · PDF fileThe information in this publication has been...