Embedded system design psoc lab report

NATIONAL INSTITUTE OF TECHNOLOGY CALICUT

Department of Electronics and Communication Engineering

Monsoon 2016

EMBEDDED SYSTEM DESIGN LAB REPORT

SUBMITTED BY

BHUKYA RAMESH NAIK

PSOC LAB REPORT NITC

ECED Page 2

TABLE OF CONTENTS:

S.NO

NAME OF THE EXPERIMENT

PAGE.NO

1

BLINKING LEDS

A. Blink a LED at a low frequenc 4

B. Running-light effect using 4 LEDs. 5

2

SWITCH INTERFACE

A. LED toggle when a push button is pressed 7

B. 4-bit binary counter 9

3

LCD INTERFACE

A. Scroll a message across the LCD 11

B. Print decimal number on the LCD 12

4

STOP WATCH (10 seconds) 14

5

TIMERS 16

6

PROGRAMMABLE GAIN AMPLIFIER 18

7

PWM 21

8

ANALOG TO DIGITAL CONVERTER 23

9

PSoC 4

A. Blink led using software 26

B. Blink led using hardware 29

10

BLINK LED USING PWM 32


ECED Page 3

11

TOGGLE RGB LED

A.Toggle using software 35

B.Toggle using interrupt 38

12

CAPSENSE 42

13

PROJECT

CONTROLLING HOME APPLIANCES USING DTMF 46

PSOC LAB

ECED

AIM:

• Blink a LED at a low frequency using

BLOCK DIAGRAM:

PORT CONNECTIONS:

LED CONFIGURATION

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all Uservoid delay( void ); void main( void ) LED_1_Start(); LED_1_Switch( 1);


EXPERIMENT-1 A.BLINKING LED

Blink a LED at a low frequency using delay( ) loop

PORT CONFIGURATION

// part specific constants and macros // PSoC API definitions for all User

); // Turn on LED

PART A

REPORT NITC

Page 4

PORT CONFIGURATION

PSOC LAB

ECED

while ( 1) LED_1_Invert(); delay( ); void delay( void ) int i= 0; for (i = 0;i < 20000 ; i++ )

RESULTS: The program is executed successfully

AIM:

• To create a running-light effect using 4 LEDs without using the LED BLOCK DIAGRAM:

PORT CONNECTIONS:


; i++ ) ;

executed successfully and output is verified on PSoC1 kit.

B. RUNNING LEDS

light effect using 4 LEDs without using the LED

REPORT NITC

Page 5

User Module


ECED Page 6

PORT CONFIGURATION C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules void main( void ) while ( 1) int i; PRT0DR= 0x01 ; for (i= 0;i<= 4000 ;i++); PRT0DR= 0x02 ; for (i= 0;i<= 4000 ;i++); PRT0DR= 0x04 ; for (i= 0;i<= 4000 ;i++); PRT0DR= 0x08 ; for (i= 0;i<= 4000 ;i++);

RESULT: The program is executed successfully and output is verified on PSoC1 kit.

PSOC LAB

ECED

AIM:

• To make a LED toggle when a push button is pressed.

BLOCK DIAGRAM:

PORT CONNECTIONS

C CODE:

#include <m8c.h> // part specific constants and macros#include "PSoCAPI.h" // PSoC API definitions for all void main( void )


EXPERIMENT - 2 A. SWITCH INTERFACE

make a LED toggle when a push button is pressed.

PORT CONFIGURATION

// part specific constants and macros // PSoC API definitions for all User Modules

REPORT NITC

Page 7

User Modules


ECED Page 8

int previousState= 0, ledState= 0; while ( 1) PRT0DM0= 0x00 ; PRT0DM1= 0x00 ; PRT0DM2= 0x00 ; //Drive mode of PORT 0 is configured as Pull-down for reading status of Switch PRT1DM0= 0x0F ; PRT1DM1= 0x00 ; PRT1DM2= 0x00 ; //Drive mode of PORT 1 is configured as Strong. if (PRT0DR & 0X01) if (previousState== 0) if (ledState== 0) PRT1DR= 0x01 ; ledState= 1; previousState= 1; else PRT1DR= 0x00 ; ledState= 0; previousState= 1; else previousState= 0;

RESULTS: The program is executed successfully and output is verified on PSoC1 kit.

PSOC LAB

ECED

BAIM:

• To create a 4-bit binary counter, BLOCK DIAGRAM:

PORT CONNECTIONS:

LED CONFIGURATION

C CODE:

#include <m8c.h> // part specific constants and macros#include "PSoCAPI.h" // PSoC API definitions for all User void main( void )


B. 4 BIT BINARY COUNTER

bit binary counter, that counts up when a push button is pressed.

PORT CONFIGURATION


REPORT NITC

Page 9

that counts up when a push button is pressed.

Modules


ECED Page 10

int x= 1; PRT1DR = 0x00 ; while ( 1) if (PRT0DR & 0x01 ) //Checks the state of the button. If the button is pressed then it will execute. if (x== 1) PRT1DR += 0x01 ; //Turns the LED On. x= 2; else x= 1;


PSOC LAB

ECED

AIM: • To scroll a message across the LCD.

BLOCK DIAGRAM:

PORT CONNECTIONS:

PORT CONFIGURATION LC

C CODE:

#include <m8c.h> // part specific constants and macros#include "PSoCAPI.h" // PSoC API definitions for all User Modules void main( void ) int i,j; char theStr1[] = " RAMESH NAIK "char theStr2[] = " JAMPU RAJU " LCD_1_Start();


EXPERIMENT - 3 A. LCD INTERFACE

scroll a message across the LCD.

LCD CONFIGURATION


" RAMESH NAIK " ; " JAMPU RAJU " ; // Define RAM string

// Initialize LCD

REPORT NITC

Page 11

// PSoC API definitions for all User Modules

PSOC LAB

ECED

while ( 1) for (i = 15,j= 0;i >= 0&& j<= 15

int k; LCD_1_Init(); LCD_1_Position( for (k = 0;k < 7000 LCD_1_PrString(theStr1); LCD_1_Position( for (k = 0;k < 7000 LCD_1_PrString(theStr2); for (k = 0;k < 7000

RESULTS: The program is executed successfully and output is

AIM: • To code a function to display decimal numbers on the LCD

BLOCK DIAGRAM:

PORT CONNECTIONS:


15;i --,j++)

LCD_1_Position( 0,i); 7000 ; k++);

LCD_1_PrString(theStr1);

LCD_1_Position( 1,j); 7000 ; k++);

LCD_1_PrString(theStr2);

7000 ; k++);

The program is executed successfully and output is verified on PSoC1 kit.

B. LCD INTERFACE

a function to display decimal numbers on the LCD

REPORT NITC

Page 12


ECED Page 13

PORT CONFIGURATION LCD CONFIGURATION

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules void lcd_print_int( longint value); void tostring( char str[], longint num); void main( void ) longint i= 150218505 ; lcd_print_int(i); void lcd_print_int( longint value) char str[ 15]; tostring(str,value); LCD_1_Start(); LCD_1_Position( 0, 0); LCD_1_PrString(str); return ; void tostring( char str[], longint num) longint i, rem, len = 0, n; n = num; while (n != 0) len++; n=(n/ 10); for (i = 0; i<len; i++) rem = num % 10; num = num / 10; str[len - (i + 1)] = rem + '0' ; str[len] = '\0' ;


PSOC LAB

ECED

AIM: • To create a 10 seconds stop watch

BLOCK DIAGRAM:

PORT CONNECTIONS:

PORT CONFIGURATION LC

C CODE:

#include <m8c.h> // part specific constants and macros#include "PSoCAPI.h" // PSoC API definitions for all User #include <string.h> #include <stdlib.h>


EXPERIMENT -4 STOP WATCH

stop watch

PORT CONFIGURATION LCD CONFIGURATION


REPORT NITC

Page 14

D CONFIGURATION

Modules


ECED Page 15

void lcd_print_int( int value); void main( void ) int i,k,l; while ( 1) if (PRT1DR &0x01 ) PRT0DR= 0x00 ; for (k= 10;k>= 0;k--) lcd_print_int(k); for (l= 0;l< 32767 ;l++); for (l= 0;l< 32767 ;l++); PRT0DR= 0x01 ; void lcd_print_int( int value) char out[ 10]; itoa(out,value, 10); LCD_1_Init(); LCD_1_Position( 0, 5); LCD_1_PrString(out);


PART B

PSOC LAB

ECED

TIMER

AIM: • To generate a 1kHz square wave with 50% duty

BLOCK DIAGRAM:

PORT CONNECTIONS:

CLOCK SETTINGS


EXPERIMENT –5 TIMER

generate a 1kHz square wave with 50% duty-cycle using a Timer module

SETTINGS TIMER CONFIGURATION

REPORT NITC

Page 16

cycle using a Timer module


ECED Page 17

CONNECTION DIAGRAM

OUTPUT INTERCONNCTION

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules void main( void ) Timer8_1_Start(); while ( 1);


PSOC LAB

ECED

PROGRAMMABLE GAIN AMPLIFIER

AIM: • To make a digital variable gain amplifier

BLOCK DIAGRAM:

PORT CONNECTIONS:

CONFIGURATIONS


EXPERIMENT –6

PROGRAMMABLE GAIN AMPLIFIER

To make a digital variable gain amplifier.

REPORT NITC

Page 18


ECED Page 19

CONNECTION DIAGRAM

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules void delay() int j; for (j= 0;j< 10000 ;j++); void main( void ) int x= 0; PGA_1_Start(PGA_1_MEDPOWER); while ( 1) if (PRT1DR & 0x01 ) x=x+ 1; delay(); switch (x%4) case 0:PGA_1_SetGain(PGA_1_G1_00); LCD_1_Start(); LCD_1_Position( 0, 3); LCD_1_PrCString( "Gain is 1" ); break ; case 1:PGA_1_SetGain(PGA_1_G2_00); LCD_1_Start(); LCD_1_Position( 0, 3); LCD_1_PrCString( "Gain is 2" ); break ; case 2:PGA_1_SetGain(PGA_1_G4_00); LCD_1_Start(); LCD_1_Position( 0, 3);


ECED Page 20

LCD_1_PrCString( "Gain is 4" ); break ; case 3:PGA_1_SetGain(PGA_1_G16_0); LCD_1_Start(); LCD_1_Position( 0, 3); LCD_1_PrCString( "Gain is 16" ); break ; //LCD_1_Control(LCD_1_Clear_Home);


PSOC LAB

ECED

AIM: • To make a LED glow at different brightness levels using a

BLOCK DIAGRAM:

PORT CONNECTIONS:

CONFIGURATIONS


EXPERIMENT -7

PWM

To make a LED glow at different brightness levels using a PWM module

REPORT NITC

Page 21

PWM module


ECED Page 22

CONNECTION DIAGRAM

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules #include <stdlib.h> #include <stdio.h> void delay(); void delay() int j; for (j= 0;j< 10000 ;j++); void main( void )

int x= 0; PWM8_1_Start();

while ( 1) if (PRT1DR & 0x01 ) x=x+ 1; delay(); switch (x%4) case 0:PWM8_1_WritePulseWidth( 10);delay(); break ; case 1:PWM8_1_WritePulseWidth( 50);delay(); break ; case 2:PWM8_1_WritePulseWidth( 100 );delay(); break ; case 3:PWM8_1_WritePulseWidth( 150 );delay(); break ;


PSOC LAB

ECED

AIM: • To make a simple voltmeter using ADC and LCD

BLOCK DIAGRAM:

PORT CONNECTIONS:

ADC CONFIGURATIONCLOCK SETTINGS


EXPERIMENT-8

ADC

To make a simple voltmeter using ADC and LCD

ADC CONFIGURATIONCLOCK SETTINGS

REPORT NITC

Page 23


ECED Page 24

CONNECTION DIAGRAM

C CODE:

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules #include <string.h> void tostring( char str[], longint num) longint i, rem, len = 0, n; n = num; while (n != 0) len++; n=(n/ 10); for (i = 0; i<len; i++) rem = num % 10; num = num / 10; str[len - (i + 1)] = rem + '0' ; str[len] = '\0' ; for (i=len;i>=len- 4;i--) str[i+ 1]=str[i]; str[i+ 2]= '.' ; void delay( int del) int i,j; for (i= 0;i<del;i++) for (j= 0;j< 2000 ;j++); int power( int a, int x ) int temp= 1,i; for (i= 0;i<x;i++) temp=temp*a; return temp;


ECED Page 25

void main( void ) int data,i,len; char str[ 15]; M8C_EnableGInt; PGA_1_SetGain(PGA_1_G1_00); PGA_1_Start(PGA_1_MEDPOWER); ADCINC_1_Start(ADCINC_1_MEDPOWER); ADCINC_1_GetSamples( 0); LCD_1_Start(); while ( 1) while (ADCINC_1_fIsDataAvailable()== 0); data=ADCINC_1_iGetData(); ADCINC_1_iClearFlagGetData(); delay( 5); tostring(str,data); LCD_1_Init(); LCD_1_Position( 0, 5); LCD_1_PrString(str);


PSOC LAB

ECED

AIM :

Blink the RGB LED at a frequency of 1Hz using the inbuilt delay function CyDelay() and configure RGB as RED COMPONENTS USED Creator Components:

• CyPins Hardware Used:

• PSoC 4 Pioneer Kit

BLOCK DIAGRAM

SCHEMATIC DIAGRAM


EXPERIMENT-9 A. BLINK LED

Blink the RGB LED at a frequency of 1Hz using the inbuilt delay function CyDelay()

SET-3

REPORT NITC

Page 26

Blink the RGB LED at a frequency of 1Hz using the inbuilt delay function CyDelay()


ECED Page 27

SPECIFICATIONS OF THE COMPONENTS/MODULES USED

• Digital output pin red with HW connection disabled

PIN CONFIGURATIONS :


ECED Page 28

C CODE #include <project.h> int main() for (;;) led_Write(0); CyDelay(500); led_Write(1); CyDelay(500);

INFERENCE/RESULT/CONCLUSION

• Hardware connection should be disabled if external hardware is not used. • RGB LED inside PSoC pioneer kit is active low.

RESULTS: The program was executed successfully and desired output was obtained.

PSOC LAB

ECED

B. BLINK LED USING HARDWAREAIM

Blink the RGB LED at a frequency of 1Hz using hardware connections only and configure RGB as RED COMPONENTS USED Creator Components:

• CyPins • Toggle Flip-Flop[1.1v] • Logic High • Clock

Hardware Used:

• PSoC 4 Pioneer Kit BLOCK DIAGRAM

SCHEMATIC DIAGRAM



BLINK LED USING HARDWARE

Blink the RGB LED at a frequency of 1Hz using hardware connections only and configure

Flop[1.1v]


REPORT NITC

Page 29

Blink the RGB LED at a frequency of 1Hz using hardware connections only and configure



ECED Page 30

• T flip-flop is rising edge triggered internally

PIN CONFIGURATIONS :


ECED Page 31

C CODE #include <project.h> int main()


• PSoC have the flexibility to use to complete a task with hardware connections only. • Reduction in code length reduces the memory usage and workload of processor. • T- flip-flop is positive edge triggered


PSOC LAB

ECED

EXPERIMENTBLINK LED USING

AIM: Blink two LEDs (say RED and GREEN in RGB module) alternatively using TPCWM component with duty cycle 50% COMPONENTS USED: Creator components:

• TCPWM[v1.0] • Clock[v2.10] • cy-Pins1 • cy-constant: Logic Low ’0’

BLOCK DIAGRAM:

SCHEMATIC DIAGRAM


EXPERIMENT-10 BLINK LED USING PWM

Blink two LEDs (say RED and GREEN in RGB module) alternatively using TPCWM component

constant: Logic Low ’0’ RGB LED

REPORT NITC

Page 32

Blink two LEDs (say RED and GREEN in RGB module) alternatively using TPCWM component


ECED Page 33

PIN CONFIGURATION: Pin_1: P1[6] Pin_2: 0[2]

CODE #include <project.h> int main() for (;;) PWM_1_Start();

MODULE SPECIFICATIONS


ECED Page 34

PWM ALIGNMENT:


• TCPWM[v1.0] is down counter. • To blink LEDs, period value should be properly set and timer register contents could be

captured to get required output. RESULTS: The program was executed successfully and desired output was obtained.

PSOC LAB

ECED

AIM: Toggle RGB Led in the kit between RED > GREEN > BLUE when a switch is pressed, Implement by Polling Gpio pin status. COMPONENTS USED: Creator components.

• Cy pins Hardware used: No external hardware is used. RGB BLOCK DIAGRAM:

SCHEMATIC DIAGRAM

PORT ASSIGNMENT

red : P1[6]; green: P0[2]; blue: P0[3] ; switch1: P0[7]


EXPERIMENT-11 A. TOGGLING RGB LED

RGB Led in the kit between RED > GREEN > BLUE when a switch is pressed, Implement

No external hardware is used. RGB LED and push button switch is used.


REPORT NITC

Page 35

RGB Led in the kit between RED > GREEN > BLUE when a switch is pressed, Implement


ECED Page 36

MODULE SPECEFICATION

• Pushbutton hardware connection enabled and drive mode resistive pull up mode

CODE: #include <project.h> void main() while (1) while (sw_Read()==1); while (sw_Read()==0);


ECED Page 37

CyDelay(500u); red_Write(0); green_Write(1); blue_Write(1); while (sw_Read()==1); while (sw_Read()==0); CyDelay(500u); red_Write(1); green_Write(0); blue_Write(1); while (sw_Read()==1); while (sw_Read()==0); CyDelay(500u); red_Write(1); green_Write(1); blue_Write(0);


• Push button in PSoC 4 pioneer kit is connected to ground. When switch is pressed connected port receives active low signal. So the drive mode of the switch should be in pull up mode.

• RGB LED s are inside the same casing, turning ON more than one will result in

complementary colours. So care should be taken turning ON and OFF each of them in practical applications.

• Hardware (edge triggering) or software measures should be taken while using a switch

in order to avoid false transitions.


PSOC LAB

ECED

B.TOGGLING USING INTERRUPTAIM: Toggle RGB Led in the kit between RED > GREEN > BLUE when a switch is pressed, Implement byGpio pin Interrupt.COMPONENTS USED Creator components:

• Cy pins • Cy isr

Hardware used: • No external hardware is used. RGB LED and push button switch is used.

BLOCK DIAGRAM:

SCHEMATIC DIAGRAM

PORT ASSIGNMENT



B.TOGGLING USING INTERRUPT

RGB Led in the kit between RED > GREEN > BLUE when a switch is pressed, Implement byGpio pin Interrupt.


green: P0[2]; blue: P0[3] ; switch1: P0[7]

REPORT NITC

Page 38

RGB Led in the kit between RED > GREEN > BLUE when a switch is



ECED Page 39

MODULE SPECEFICATION

• Interrupt enabled in switch

• Interrupt vector with priority settings

Isr with default settings


ECED Page 40

• Output pins with hardware connection disabled

CODE: #include <project.h> CY_ISR(swt_int) while (swt_Read()); CyDelay(500u); Red_Write(0); Green_Write(1); Blue_Write(1); while (swt_Read()); CyDelay(500u); Red_Write(1); Green_Write(0); Blue_Write(1); while (swt_Read()); CyDelay(500u); Red_Write(1); Green_Write(1); Blue_Write(0);


ECED Page 41

swt_ClearInterrupt(); int main() CyGlobalIntDisable; isr_1_Start(); isr_1_SetVector(swt_int); CyGlobalIntEnable; /* Uncomment this line to enable global interrupts. */ while (1);


• Interrupts can be generated from input module by activating it. • Priority of interrupts and interrupt vector can be set.

• ISR function should be activated and global interrupts should be enabled before using

interrupt.


PSOC LAB

ECED

AIM: Configure the CapSense module in the Pioneer Kit as button and on sensing capacitive touch at

each button,glow an led use three Capsense buttons to glow RED, GREEN, BLUE in the RGB module, and for remaining two Capsense buttons by wiring additional Leds to Gpio pin

COMPONENTS USED: Creator components:

• Capsensecsd module • Cy-pins

Hardware used: LEDs . BLOCK DIAGRAM

SCHEMATIC DIAGRAM:


EXPERIMENT-12 CAPSENSE

the CapSense module in the Pioneer Kit as button and on sensing capacitive touch at each button,glow an led use three Capsense buttons to glow RED, GREEN, BLUE in the RGB module, and for remaining two Capsense buttons by wiring additional Leds to Gpio pin

SCHEMATIC DIAGRAM:

REPORT NITC

Page 42

the CapSense module in the Pioneer Kit as button and on sensing capacitive touch at each button,glow an led use three Capsense buttons to glow RED, GREEN, BLUE in the RGB module, and for remaining two Capsense buttons by wiring additional Leds to Gpio pins.


ECED Page 43

PIN CONFIGURATION:

CODE: #include <project.h> int main() CyGlobalIntEnable; CapSense_1_Start(); CapSense_1_InitializeAllBaselines(); for (;;) CapSense_1_UpdateEnabledBaselines(); CapSense_1_ScanEnabledWidgets(); while (CapSense_1_IsBusy()!=0); if (CapSense_1_CheckIsWidgetActive(CapSense_1_BUTTON0 __BTN))


ECED Page 44

Red_Write(0); Green_Write(1); Blue_Write(1); led2_Write(0); led1_Write(0); if (CapSense_1_CheckIsWidgetActive(CapSense_1_BUTTON1 __BTN)) Red_Write(1); Green_Write(0); Blue_Write(1); led2_Write(0); led1_Write(0); if (CapSense_1_CheckIsWidgetActive(CapSense_1_BUTTON2 __BTN)) Red_Write(1); Green_Write(1); Blue_Write(0); led2_Write(0); led1_Write(0); if (CapSense_1_CheckIsWidgetActive(CapSense_1_BUTTON3 __BTN)) Red_Write(1); Green_Write(1); Blue_Write(1); led1_Write(0); led2_Write(1); if (CapSense_1_CheckIsWidgetActive(CapSense_1_BUTTON4 __BTN)) Red_Write(1); Green_Write(1); Blue_Write(1); led1_Write(1); led2_Write(0);

MODULE SPECIFICATION:

• Output pins with hardware connection disabled


ECED Page 45


• In capsense the scanning of widgets and capacitance measurements takes some time, so proper delay or looping should be given before using the output values.

• For switch operation button mode is used in capsense. RESULTS:

• The program was executed successfully and desired output was obtained.


ECED Page 46

PROJECT CONTROLLING HOME APPLIANCES USING DTMF

ABSTRACT Traditionally electrical appliances in a home are controlled via switches that

regulate the electricity to these devices. As the world gets more and more technologically

advanced, we find new technology coming in deeper and deeper into our personal lives

even at home. Home automation is becoming more and more popular around the world and

is becoming a common practice. The process of home automation works by making

everything in the house automatically controlled using technology to control and do the jobs

that we would normally do manually.

This project proposes a unique system for Home automation utilizing Dual Tone

Multi Frequency (DTMF) that is paired with a wireless module to provide seamless wireless

control over many devices in a house. This user console has many keys, each corresponding

to the device that needs to be activated. The encoder encodes the user choice and sends via a

transmitter. The receiver receives the modulated signal and demodulates it and the user

choice is determined by the DTMF decoder. Based upon this the required appliance is

triggered.

SOFTWARE TOOL: PSOC DESIGNER 5.4 COMPONENTS: DTMF Circuit Consists of Various Components:

Resistors

LEDs

Capacitors

Crystal Oscillator

ICs

Overview of Software Used:


ECED Page 47

In this project we use Psoc1 designer software. In which we can use two languages for coding.

1. Embedded C

2. Assembly language

Embedded C:

C is probably the most widely used programming language today. It has a number of

features that make it a good choice for both small-scale embedded projects, as well as large-scale

projects. Features like:

• It is easier and less time consuming.

• C is easier to modify and update.

DTMF BASED HOME AUTOMATION

Dual Tone Multiple frequency techniques used to control home appliances. By using this we can control lights, fans.

Fig. Block Diagram

Description:

The brain of the circuit is the M8C processor of PSoC1. The M8C microprocessor

examines incoming signals through DTMF decoder and controls the outputs by relays. The

DEVICE 3

CELL -

PHONE

PSOC 1

DTMF

D ECODER

REGULATED

POWER SUPPLY

DEVICE 1

DEVICE 2

DEVICE 4

DEVICE 5


ECED Page 48

audio output from the cell phone is connected to the input of DTMF decoder. The incoming call

is answered by the cell phone.

DTMF detection and decoding is provided by DTMF decoder block. An IC MT 8870, is a

complete DTMF receiver, which is able to detect and decode all 16 DTMF tone pairs into a 4-bit

code. When a valid DTMF digit is detected the 4-bit code is available at the output pins and a

VALID SIGNAL output, is set to logic high. For its operation the integrated circuit requires a

clock signal, generated in this case by the quartz crystal of 3.579545MHz.

In a DTMF signal generation, a DTMF keypad could be used for digit entry, when a button is

pressed, both the row and column tones are generated by the telephone or touch tone instrument.

These two tones will be distinctive and different from tones of other keys. So there is a low and

high frequency associated with a button, it is essentially the sum of two waves is transmitted.

1. DTMF decoder IC (M-8870)

2. Resistors (100kΩ; 70kΩ; 390kΩ)

3. Capacitors (0.1µFx 2)

4. Crystal oscillator (3.579545MHz)

The operation of DTMF method are as follows:

• Caller generates a dial tone consisting of two frequencies. It is transmitted via the telephone line (communication media).

• Telephone exchange consists of a DTMF decoder, which decodes the frequencies in to digital code.

• These codes are the address of destination subscriber; it is read and processed by a computer

which connects caller to the destination subscriber.

Working of DTMF decoder circuit.


ECED Page 49

• DTMF keypads are employed in almost all landline and mobile handsets. Thus this technology is used in the telephone switching centres to identify the number dialled by the caller.

• The decoder distinguishes the DTMF tones and produces the binary sequence equivalent to key pressed in a DTMF (Dual Tone Multi Frequency) keypad.

• The circuit uses M-8870 DTMF decoder IC which decodes tone generated by the keypad of cell phone.

• DTMF signals can be tapped directly from the microphone pin of cell phone device. Cut the microphone wire and you will get two wires red and green. The red wire is the DTMF input to the circuit.

• The signals from the microphone wire are processed by the DTMF decoder IC which generates an equivalent binary sequence as a parallel output like Q1, Q2, Q3, and Q4

• There is an inbuilt Op amp present inside the M-8870 decoder IC. The electrical signals from microphone pin are fed to inverting input of the Op Amp via a series of resistance (100kΩ) and capacitance (0.1 µF).

• The non inverting input of Op-amp is connected to a reference voltage (pin4 -VREF). The voltage at VREF pin is Vcc/2.

• Pin 3 (GS) is the output of internal Op Amp, the feedback signal is given by connecting the output pin (pin3- GS) to inverting input pin (pin2- IN-) through a resistor (270kΩ).

• The output of Op Amp is passed through a pre filter, low group and high group filters (filter networks). These filters contain switched capacitors to divide DTMF tones into low and high group signals (High group filters bypass the high frequencies whereas low group filter pass low frequencies).

• Next processing sections inside the IC are frequency detector and code detector circuits. Filtered frequency passed through these detectors.

• At last the four digit binary code is latched at the output of M-8870 DTMF decoder IC.

Uses of other pins:

• The entire process from frequency detection to latching of the data, is controlled by steering


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control circuit consisting of St/GT, Est pins, resistor (390kΩ) and a capacitor (0.1µF).

• 5th Pin, INH is an active high pin, inhibits detection of A, B, C, D tones of character.

• 6th Pin, PWDN is an (active high), inhibits the working of oscillator thus stops the working of our circuit.

• The 10th pin 10; TOE is the output enable pin which is active high logic and enables the latching of the data on the data pins Q0, Q1, Q2, and Q3.

• 15th Pin StD is the Data valid pin, turn out to be high on detection of valid DTMF tone or else it remains low.

• Pins 7 (OS1) and 8 (OS2) are used to connect crystal oscillator. An oscillator of frequency 3.579545 MHz is used here.

Each row and column of the keypad corresponds to a certain tone and creates a specific frequency. Each button lies at the intersection of the two tones.

For each pair, one of the tones is selected from a low group of four frequencies, and the other from a high group of four frequencies. The correct detection of a digit requires both a valid tone pair and the correct timing intervals.

Working of DTMF Based Home Automation:

When you press any keys in your mobile Phone while call in progress, the other person will hear

some tones with respect to keys pressed. These tones are based on the DTMF (Dual Tone Multi

Frequency) technology. Data transmitted in terms of pair of tones. The receiver detects the valid

frequency pair and gives the appropriate BCD code as the output of the DTMF decoder IC.

DTMF signal can be tapped directly from the microphone pin of cell phone device. DTMF signal

can be tapped directly from the microphone pin of cell phone device.

See the figure below, Cut the microphone wire and you will be able to see 4 wires. Among these

wires you need only 2 wires Ground and Right as shown in the below figure.

Fig Headphone jack

Select the right wire and connect it as the DTMF input to the decoder circuit. Ground should be

connected to common ground of our circuit. The signals from the microphone wire are processed

by the DTMF decoder IC which generates the equivalent binary sequence as a parallel output as

Q1, Q2, Q3, and Q4.

DTMF Low and High frequency tones and decoded output


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Button

Low DTMF

frequency

(Hz)

High DTMF

frequency

(Hz)

Binary coded output

Q1 Q2 Q3 Q4

1 697 1209 0 0 0 1 2 697 1336 0 0 1 0 3 697 1477 0 0 1 1 4 770 1209 0 1 0 0 5 770 1336 0 1 0 1 6 770 1477 0 1 1 0 7 852 1209 0 1 1 1 8 852 1336 1 0 0 0 9 852 1477 1 0 0 1 0 941 1336 1 0 1 0 * 941 1209 1 0 1 1 # 941 1477 1 1 0 0

When we press the digit 1 on the keypad, you generate the tones 1209 Hz and 697 Hz. Pressing

the digit 2 will generate the tones 1336 Hz and 697 Hz. Sure, the tone 697 is the same for both

digits, but it takes two tones to make a digit and the equipment knows the difference between the

1209 Hz that would complete the digit 1, and a 1336 Hz that completes a digit 2.

When the user has entered what they believe to be the correct code the pound key (#) is pressed

on the phone pad and the microprocessor looks at the code it has stored in memory. The received

code is then compared against a firmware defined code. If the code does not match, the software

begins counting the failed access attempts.

If the failed attempt count reaches three, the microprocessor enters a three-minute lockdown

mode where further remote access to the system is denied. This lockdown mode is designed to

discourage unauthorized access to the system. If the user believes that they have pressed a wrong

key, they can clear the code stored in memory by pressing the star (*) key with no penalty. If the

pound button is pressed and an incorrect code was entered, there is no way for the user to delete

the failed attempt, except by hanging up and redialling. If the system is in lockdown mode when a

person attempts to dial in the system, it will not respond until the three-minute lockdown has

finished running its course.

Once the correct code sequence has been entered and confirmed correct by the microprocessor,

the user is granted access to activate any number of the desired subsystems. The subsystems are

numbered 0-9, *, and #. The subsystem to activate is chosen by DTMF decoding just as the code

was entered. At this point in the program any key press will activate a subsystem and a subsystem


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can be activated multiple times if the user desires. As the subsystems are self-contained, they only

require a pulse to begin their respective tasks. To disconnect from the system, the user simply

hangs up the phone that they are calling from. The subsystems will finish their jobs with no need

for the user to stay on the line. By using a band-split filter, the signal is broken into two sine wave

components. The peaks of each sine wave are counted over some known time frame. This will tell

the user the period of each sine wave.

By knowing the period, users can know the operating frequency of each sine wave. Once the

frequencies are calculated, they are compared against valid DTMF frequency ranges. If a valid

frequency is found to correspond to the row and column of a DMTF tone, a binary output is

placed on the output of the CM8870. A control line is driven high on the chip to indicate that a

valid code has been decoded and is present on the four-bit binary port. This decoded DTMF tone

will remain present on the output port until the CM8870 receives an enable signal from the

microprocessor controlling circuitry. At this point, the CM8870 will start the DTMF decoding

process over.


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FLOW CHART:

Start

Wait for Password

Is

password

correct ?

Control Devices

Is timer

<15 sec?

YES

YES No

No


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CODE

#include <m8c.h> // part specific constants and macros #include "PSoCAPI.h" // PSoC API definitions for all User Modules voidSet_Drive_Mode(int Port , int Pin , int Mode); voidDigital_Write(int Port , int Pin , int Value); void main(void) int j=0,k=0; char password[2]; intisAuthenticated=0; Set_Drive_Mode(1 , 0 , 0); //Set drive mode as pull down Set_Drive_Mode(1 , 1 , 0); Set_Drive_Mode(1 , 2 , 0); Set_Drive_Mode(1 , 3 , 0); Set_Drive_Mode(0 , 0 , 1); //Set drive mode as strong Set_Drive_Mode(0 , 1 , 1); Set_Drive_Mode(0 , 2 , 1); Set_Drive_Mode(0 , 3 , 1); Set_Drive_Mode(0 , 4 , 1); while (1) //Infinite loop while (isAuthenticated==0) //wait’s for pass word if(PRT1DR == 0x0B) password[0]='B'; if(PRT1DR == 0x0C) if (password[0]=='B') isAuthenticated=1; //If password is *# password[0]='';

while(isAuthenticated==1) //Iterates until i sAuthenticated=0 for (j=0;j<=32000 ;j++) //for timer operation if(PRT1DR == 0x01) Digital_Write(0,0,1); if(PRT1DR == 0x02) Digital_Write(0,0,0); if(PRT1DR == 0x03)


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Digital_Write(0,1,1); if(PRT1DR == 0x04) Digital_Write(0,1,0); if(PRT1DR == 0x05) Digital_Write(0,2,1); if(PRT1DR == 0x06) Digital_Write(0,2,0); if(PRT1DR == 0x07) Digital_Write(0,3,1); if(PRT1DR == 0x08) Digital_Write(0,3,0); if(PRT1DR == 0x09) Digital_Write(0,4,1); if(PRT1DR == 0x0A) Digital_Write(0,4,0); k=k+1; j=0; if (k==3) k=0; isAuthenticated=0; voidSet_Drive_Mode(int Port , int Pin , int Mode) switch (Port) case 0: if (Mode%2==1) PRT0DM0 |= 1<<Pin; else PRT0DM0 &= ~(1<<Pin); if ((Mode/2)%2==1) PRT0DM1 |= 1<<Pin; else


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PRT0DM1 &= ~(1<<Pin); if ((Mode/4)%2==1) PRT0DM2 |= 1<<Pin; else PRT0DM2 &= ~(1<<Pin); break; case 1: if (Mode%2==1) PRT1DM0 |= 1<<Pin; else PRT1DM0 &= ~(1<<Pin); if ((Mode/2)%2==1) PRT1DM1 |= 1<<Pin; else PRT1DM1 &= ~(1<<Pin); if ((Mode/4)%2==1) PRT1DM2 |= 1<<Pin; else PRT1DM2 &= ~(1<<Pin); break; case 2: if (Mode%2==1) PRT2DM0 |= 1<<Pin; else PRT2DM0 &= ~(1<<Pin); if ((Mode/2)%2==1) PRT2DM1 |= 1<<Pin; else PRT2DM1 &= ~(1<<Pin); if ((Mode/4)%2==1) PRT2DM2 |= 1<<Pin; else PRT2DM2 &= ~(1<<Pin);


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break; voidDigital_Write(int Port , int Pin , int Value) switch (Port) case 0: if (Value==1) PRT0DR |= 1<<Pin; else PRT0DR &= ~(1<<Pin); break; case 1:if (Value==1) PRT1DR |= 1<<Pin; else PRT1DR &= ~(1<<Pin); break; case 2: if (Value==1) PRT2DR |= 1<<Pin; else PRT2DR &= ~(1<<Pin); break;

APPLICATIONS:

• Home Automation

• Telephone Answering Machine(IVR)

• Remote controlling System

CONCLUSION

This project presents a DTMF based home appliances controlling by M8C of PSoC1.Experimental

work has been carried out carefully. Here we are controlling 5 home appliances controlling through

DTMF technology effectively secured with password and timer. Here very easy to use for any

applications with the help of M8C Processor of PSoC1.


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REFERENCES

[1] Embedded Systems- An Integrated Approach by Lyla B. Das.

[2] DTMF Based Remote Control System - R. Sharma, K. Kumar, and S. Viq, IEEE International

Conference ICIT, pp. 2380-2383, December 2006.

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