Embedded System Desgin : Microcontroller

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Attepmt to Accessing Keyboad Up and down Key by C programm for a project

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<pre class="brush:csharp"></pre>
<pre class="brush:c++"> *<b> main.c</b>
*
* Created on: Aug 12, 2017
*      Author: thannara123

#include<stdio .h="">
#define FALSE 0
#define TRUE 1 // 0r //!FALSE
struct menu
{
   char menu_up_key;
   char menu_down_key;
   char menu_enter_key :1; // bit feild 1 bit
};
struct menu s1= {0}; //s1.menu_up-key =1;
void struct_1( struct menu,const char *menu_display[]);

int main()
{

     const char *menu_display[10];
      menu_display[0] = "Menu0";
      menu_display[1] = "Menu1";
      menu_display[2] = "Menu2";
      menu_display[3] = "Menu3";
      menu_display[4] = "Menu4";
      menu_display[5] = "menu 5";
      menu_display[6] = "menu 6";

       struct_1(s1,menu_display);
             getchar();
             return 0;

      }

void struct_1(struct menu s1 ,const char *menu_display[])
{

     char ch;
      do{
            ch=getch();

            if(ch!='\0')
            {
              ch=getch();
              if(ch=='H')
              {
               s1.menu_up_key++;
               if(s1.menu_up_key==7)
                 s1.menu_up_key =0;
            // printf("UP\n");
                  printf(" %s\n",*(s1.menu_up_key+menu_display));
               }
         else    if(ch=='P')
               {
              s1.menu_up_key--;
              if(s1.menu_up_key==-1)
                  { s1.menu_up_key =6;
                   goto here;
                  }
                //printf("down\n");

                  here:
         printf("%s\n",*(s1.menu_up_key+menu_display));

                   }

            }
               }
              while(ch!='e');// while oka key
}
</stdio></pre>
<pre class="brush:csharp">/*
* button_key.c
*
* Created: 7/30/2017 12:02:39 PM
* Author: Krishna
*/ #include <avr io.h="">
#include "delay.h"
#include "button_key.h"
#include "lcd.h"

void menu_key_display(struct menu s1,const char *menu_display[]);
void UP_Down_Keyvalue(struct menu s1,int i,int j);

/* Function Key Value For get key */
int Key_pressed(void)
{
while(1){
    if (LEFT_S) { while(LEFT_S);return 1; }
if (RIGHT_S){ while(RIGHT_S);return 2; }
if (UP_S) { while(UP_S); return 3; }
if (DOWN_S) { while(DOWN_S);return 4 ; }
if (OK_S) { while(OK_S);return 5 ; }
}
}

/* Function Key Value For Up Key & Enter*/

void menu_key_display(struct menu s1,const char *menu_display[])
{
int ch;
   int a;
int menu_position =0;
   LCD_DisplayString(menu_display[menu_position]);
            do{

    repat:
    ch = Key_pressed();
    if(ch==1||ch==2)
    {
                  if(ch==2)
                    { if(ch==2)
                   { if(s1.menu_side_key==4)
                     s1.menu_side_key = 0;
                  LCD_Clear();
                  LCD_GoToLine(0);
                              LCD_DisplayString(*((++s1.menu_side_key)+menu_display));
         menu_position=1;

                 }
                      }
                   else if(ch==1)
                   {
                             if(ch==1)
                    {if(s1.menu_side_key==1 ||s1.menu_side_key==0)
                      {
                    s1.menu_side_key=5;
                      }
                      LCD_Clear();
                            LCD_DisplayString(*((--s1.menu_side_key)+menu_display));
          menu_position=1;
                         }
                   }
          }

    if(menu_position==0)
    goto repat;
        }while(ch!=5);

        a = s1.menu_side_key;
switch(a)
     {
case 1: // set time
          {
    LCD_Clear();
       LCD_GoToLine(0);
       LCD_DisplayString(menu_display[5]);
    LCD_GoToLine(1);
    LCD_DisplayString(" HH:MM:SS:PM/AM");
    UP_Down_Keyvalue(s1,2,4);
          break;
          }
case 2: // Set date
        {
         LCD_Clear();
         LCD_GoToLine(0);
         LCD_DisplayString(menu_display[6]);
      LCD_GoToLine(1);
      LCD_DisplayString(" DD:MM:YY");
      UP_Down_Keyvalue(s1,2,3);
         break;
        }

case 3: // set alarm
          {
         LCD_Clear();
            LCD_GoToLine(0);
         LCD_DisplayString(menu_display[7]);
      LCD_GoToLine(1);
      LCD_DisplayString(" HH:MM:SS:AM/PM");
      UP_Down_Keyvalue(s1,2,4);
          break;
             }
case 4: // set alarm
           {
            LCD_Clear();
          LCD_GoToLine(0);
          LCD_DisplayString(menu_display[8]);
    LCD_GoToLine(1);
    LCD_DisplayString(" HH:MM:SS:PM/AM");
    UP_Down_Keyvalue(s1,2,4);
          break;
            }
     }

while(Key_pressed()!=5);


}

/* Function Key Value For UP_Down Key */
void UP_Down_Keyvalue(struct menu s1,int i,int j)
{

int ch,lower,upper;
do{
    if(j==4)
     {
      if(i==2)upper=1;
      if(i==3)upper=9;
      if(i==5)upper=5;
      if(i==8)upper =5;
      if(i==9)upper =9;
     }
      if(UP_S)
      {
      while(UP_S);
      if(s1.menu_up_key==upper)
      s1.menu_up_key = lower-1;
      LCD_GoToXY(1,i);
      LCD_Printf("%d",++s1.menu_up_key);
      s1.time[i-2]=s1.menu_up_key;
      }
   else if(DOWN_S) // down

          {    while(DOWN_S);
            if (s1.menu_up_key==lower)
            s1.menu_up_key = upper+1;
            LCD_GoToXY(1,i);
            LCD_Printf("%d",--s1.menu_up_key);
      s1.time[i-2]=s1.menu_up_key;
     }
          if(RIGHT_S)

             { while(RIGHT_S);
       s1.menu_up_key=0;
          if(i==9) goto exit1;
          if(i==3||i==6)
          ++i;
          i++;
              }
      exit1:
           if (LEFT_S)
             { while(LEFT_S);
        s1.menu_up_key=0;
            if(i==2) goto exit2;
            if(i==5||i==8)
            --i;
            i--;

             }
    exit2:continue;


} while (ch!=5); // if Okay key exit loop

}

</avr></pre>
<div class="separator" style="clear: both; text-align: center;">
</div>
</div>

Attepmt to Accessing Keyboad Up and down Key by C programm for a project

Switch Bounce Tutorials

Switch Bounce

Microcontrolers may not in Human thinking frequency .Human thinking frequency is lies in some of low Hz . Microcontroler works variety range of frequency ie ,12Mhz,20 Mhz etc . In a push Button micro controller interfacing, Human and Micro controller are feels that whether the push is pressed or not in different way as follows in the graph .

Some small duration pulse due to denounce generated as multiple touch error
Hardware solution

It can be made by a resistor and a capacitor in the following manner or any other for comfortable

When ever the switch is pressed the capacitor will charge rapidly ,practically the first charge wil be across the ,capacitor ,

So we can avoid the denouncing effect .

The capacitor and the resistor will be select in accordance with time constant . as follows

For more information go here

Will be update

Switch Bounce Tutorials

Switch Bounce

Some small duration pulse due to denounce generated as multiple touch error
Hardware solution

It can be made by a resistor and a capacitor in the following manner or any other for comfortable

When ever the switch is pressed the capacitor will charge rapidly ,practically the first charge wil be across the ,capacitor ,

So we can avoid the denouncing effect .

The capacitor and the resistor will be select in accordance with time constant . as follows

For more information go here

Will be update

16 Bit Event Counter & Displaying on LCD1

An External Pulse Counter Using 8051 and Dispalying on 16x2 LCD

A circuits which is used to count the external pulses And which is displaying on an 16x2 LCD display . You can simply use this project for various purpose .It is a default project for counting Purpose.

Tutorials : -

To use 16 Bit counter we need to configure some register in 8051 as follows

TMOD Register is need to configure as follows

16 bit counter Setting with timer 0

TMOD=0x05; // Giving 0x05 it configured so .

8051 has Two Timer (each has 16 bit ) i am taking here Timer 0 It has to part First 8 bit (TL)) and the second part is (TH0) .

This timer is using to store the Pulses from the external (ie it will increment up to 65535 or FFFF)

TL0 = 0; // that timer clearing

TH0 = 0; // that timer clearing

TR0 = 1 // TR0 setting to start the counting .

Done .................................

After setting the above register as said the resulted value (counting value ) will save periodically in TL0 and TH0 . That value displaying after converting it to decimal . for LCD Tutorials Go Here

Download Her the all Project Including Proteus file
Click Here

16 Bit Event Counter & Displaying on LCD1

An External Pulse Counter Using 8051 and Dispalying on 16x2 LCD

Tutorials : -

To use 16 Bit counter we need to configure some register in 8051 as follows

TMOD Register is need to configure as follows

16 bit counter Setting with timer 0

TMOD=0x05; // Giving 0x05 it configured so .

8051 has Two Timer (each has 16 bit ) i am taking here Timer 0 It has to part First 8 bit (TL)) and the second part is (TH0) .

This timer is using to store the Pulses from the external (ie it will increment up to 65535 or FFFF)

Download Her the all Project Including Proteus file
Click Here

Design of Digital Voltmeter By using Micro-controller Part 2

Microcontroller based Digital AC Meter Part 2 Code And Circuit

First Part available here

Circuit Diagram

#include"lcd.h"
#include "adc.h"
#include "delay.h"
double volt_read_disply();
int main(void)
  
{   
     int adc_value1=0;  
  LCD_SetUp(PB_0,PB_1,PB_2,P_NC,P_NC,P_NC,P_NC,PB_4,PB_5,PB_6,PB_7);
  LCD_Init(2,16);     
     adc_init();
    
     LCD_Clear();
  LCD_GoToXY(0,0);  
  
  LCD_DisplayString("  g-Electron"); 
  _delay_ms(1000); 
  
 while(1) 
 {  
       adc_value1 =  volt_read_disply();
    LCD_GoToLine(1);  
    LCD_DisplayString(" Volt : ");    
    LCD_DisplayNumber(10,adc_value1,3);   
    LCD_DisplayString("V");  
    _delay_ms(1300);
 } 
}

double volt_read_disply()
{   int i,adc_value[40]={0}; int temp =0;
 
 adc_init();

  for(i=0; i<40;i++)                        // samples taking from 41 times 9.4milli second taken about on complte half cycle
   { 
   adc_value[i] = read_adc(0);  // reading voltage           
  }
   
  temp = adc_value[0];  
 for(i=0; i<40; i++)
 {
  if(temp<adc_value[i])
  temp=adc_value[i];
 }  
 
      return ((double)temp*0.224828935); // int to double casting
   
}

Design of Digital Voltmeter By using Micro-controller Part 2

Microcontroller based Digital AC Meter Part 2 Code And Circuit

First Part available here

Circuit Diagram

#include"lcd.h"
#include "adc.h"
#include "delay.h"
double volt_read_disply();
int main(void)
  
{   
     int adc_value1=0;  
  LCD_SetUp(PB_0,PB_1,PB_2,P_NC,P_NC,P_NC,P_NC,PB_4,PB_5,PB_6,PB_7);
  LCD_Init(2,16);     
     adc_init();
    
     LCD_Clear();
  LCD_GoToXY(0,0);  
  
  LCD_DisplayString("  g-Electron"); 
  _delay_ms(1000); 
  
 while(1) 
 {  
       adc_value1 =  volt_read_disply();
    LCD_GoToLine(1);  
    LCD_DisplayString(" Volt : ");    
    LCD_DisplayNumber(10,adc_value1,3);   
    LCD_DisplayString("V");  
    _delay_ms(1300);
 } 
}

double volt_read_disply()
{   int i,adc_value[40]={0}; int temp =0;
 
 adc_init();

  for(i=0; i<40;i++)                        // samples taking from 41 times 9.4milli second taken about on complte half cycle
   { 
   adc_value[i] = read_adc(0);  // reading voltage           
  }
   
  temp = adc_value[0];  
 for(i=0; i<40; i++)
 {
  if(temp<adc_value[i])
  temp=adc_value[i];
 }  
 
      return ((double)temp*0.224828935); // int to double casting
   
}

Transformer Configuration in Proteus

Setting up A Transformer in Proteus

The calculation Formula is L1/L2 = (V1/V2)^2

For Example: Design for 6 Volt input ,230volt 50Hz Not considered wattage just for simulation.

Assign L1 = 1H (but 1henry expectable for a 10 or 20 kW transformer)

Then L2 = 1/(230/6)^2

= 680.5293micro Henry

Transformer Configuration in Proteus

Setting up A Transformer in Proteus

The calculation Formula is L1/L2 = (V1/V2)^2

For Example: Design for 6 Volt input ,230volt 50Hz Not considered wattage just for simulation.

Assign L1 = 1H (but 1henry expectable for a 10 or 20 kW transformer)

Then L2 = 1/(230/6)^2

= 680.5293micro Henry

Design of Digital Voltmeter By using Microcontroller

Tutorial for Atmeag8 /AVR based Voltmeter

It measures the Ac voltage and shows readings in RMS value.

Basics Of AC signal

The AC signal ,its amplitude varying in accordance with time. In india AC frequency is 50Hz.

Then the Time period one full cycle ,

T = 1/frequency

T = 1/50Hz = .002second

= 20milli Second

= 10 Milli second for Half Cycle

There are a lot of methods for measuring AC volt digitally

we could find the RMS value by multipliying the Peak Voltage with 0.707.

Vrms = Peak Voltage * 0.707 .

Approximatly Indian Line AC Peak volatge is 325v.

Example :

325v *0.707 = 229.775Volt .(appro = 230Vrms).

But Microcontroller could only sense up to 5 volt as well as it couldnt sense negative values

so we cannot give 230 volt directly to It .

It can be rectify by using a Stepdown transformer ,which has an advantage of safety.

Ac voltage can be reduce by using transformer to comfortable range . (ie 0 to 5volt DC)

make the calculation as ,

The voltage Divider would give a 5 volt when the Vrms 230v. [will be more give details on the way ].

The full wave rectifier output will give to ADC of micro controller . Then do corresponding coding.

Microcontroller Section
I am using here Amega8.
we need to mesure only one half cycles repeatedly because  the waves same are repeating
Basics

I selected , the F_cpu frequency is the internal RC Oscillator 8MHz.
Atmega8 ADC uses Prescalar [frequency reducer or divider by 2th,4th etc]
Atmega ADC Prescale Frequency is in between 50Khz to 200Kz
ADC conversion time is in between 13 to 260 micro second.

ADC frequency = F_cpu / Prescaler

= 800,000HZ / 8

= 62.5KHz

At high frequency ADC conversion would be fast while at lower frequency the conversion will be more accuracy.

ADC conversion time Calculation

Conversion Time = 1/ADC frequency

= 1/62500
= 0.000016 Second
= 0.016 Milli Second
= 16 Micro Second. [At 62.500KHz]

So 16 mirco second would taken for one cycle of conversion.with 62,5KHz.

13 ADC cycles required for one conversion

ie,
13 * 16Micro Second = 230 Micro Second [approximately]
= 230us.

The Half wave has 10milli second time duration.[100000microsecond].

There the available conversion times is

= Total time period for a half cycle /one ADC conversion time

= 10000 micro second / 230 micro second

= 43.4 samples [ for one half cycleie 10 milli second]

Image Shows only 7 Samples per half cycles .in our case it is 43

And again reduced the sampling to 40 .

calculation of Vpeak

Takes the largest Vpeak from the 40 samples.

Vrms = Vpeak * .707

*****************************************************************************

Atmega8 ADC StepSize Calculation

Atmega8 uses successive approximation adc ,

The Atmega8 ADC is a 10 Bit /[ie the Maximum high value is 1023 =1111111111] at which the ADC will give fullscale Value .

The ADC require a clock as well as a reference voltage .

The resolution of ADC output decide the Step size.

ADC o/p = Vin * 1024 / Vref

Examples;

Vin =5volt , Vref =5volt

ADC o/p = 5 * 1023 /5 = 1023 [ADC highest Value]

Step Size voltage = Vref / 1023 = 0.004887 volt =4.88millivolt

One binary digit changes when 4.88volt changes takes place

Image's Step Size is 1.25 volt

*******************************************************************************************************
Go Here for Part 2

Design of Digital Voltmeter By using Microcontroller

Tutorial for Atmeag8 /AVR based Voltmeter

It measures the Ac voltage and shows readings in RMS value.

Basics Of AC signal

The AC signal ,its amplitude varying in accordance with time. In india AC frequency is 50Hz.

Then the Time period one full cycle ,

T = 1/frequency

T = 1/50Hz = .002second

= 20milli Second

= 10 Milli second for Half Cycle

There are a lot of methods for measuring AC volt digitally

we could find the RMS value by multipliying the Peak Voltage with 0.707.

Vrms = Peak Voltage * 0.707 .

Approximatly Indian Line AC Peak volatge is 325v.

Example :

325v *0.707 = 229.775Volt .(appro = 230Vrms).

But Microcontroller could only sense up to 5 volt as well as it couldnt sense negative values

so we cannot give 230 volt directly to It .

It can be rectify by using a Stepdown transformer ,which has an advantage of safety.

Ac voltage can be reduce by using transformer to comfortable range . (ie 0 to 5volt DC)

make the calculation as ,

The voltage Divider would give a 5 volt when the Vrms 230v. [will be more give details on the way ].

The full wave rectifier output will give to ADC of micro controller . Then do corresponding coding.

Microcontroller Section

I am using here Amega8.
we need to mesure only one half cycles repeatedly because  the waves same are repeating
Basics

I selected , the F_cpu frequency is the internal RC Oscillator 8MHz.

Atmega8 ADC uses Prescalar [frequency reducer or divider by 2th,4th etc]

Atmega ADC Prescale Frequency is in between 50Khz to 200Kz

ADC conversion time is in between 13 to 260 micro second.

ADC frequency = F_cpu / Prescaler

= 800,000HZ / 8



= 62.5KHz

At high frequency ADC conversion would be fast while at lower frequency the conversion will be more accuracy.

ADC conversion time Calculation

Conversion Time = 1/ADC frequency

= 1/62500

= 0.000016 Second

= 0.016 Milli Second

= 16 Micro Second. [At 62.500KHz]

So 16 mirco second would taken for one cycle of conversion.with 62,5KHz.

13 ADC cycles required for one conversion

ie,

13 * 16Micro Second = 230 Micro Second [approximately]

= 230us.

The Half wave has 10milli second time duration.[100000microsecond].

There the available conversion times is

= Total time period for a half cycle /one ADC conversion time



= 10000 micro second / 230 micro second

= 43.4 samples [ for one half cycleie 10 milli second]

Image Shows only 7 Samples per half cycles .in our case it is 43

And again reduced the sampling to 40 .

calculation of Vpeak

Takes the largest Vpeak from the 40 samples.

Vrms = Vpeak * .707

*****************************************************************************

Atmega8 ADC StepSize Calculation

Atmega8 uses successive approximation adc ,

The Atmega8 ADC is a 10 Bit /[ie the Maximum high value is 1023 =1111111111] at which the ADC will give fullscale Value .

The ADC require a clock as well as a reference voltage .

The resolution of ADC output decide the Step size.

ADC o/p = Vin * 1024 / Vref

Examples;

Vin =5volt , Vref =5volt

ADC o/p = 5 * 1023 /5 = 1023 [ADC highest Value]

Step Size voltage = Vref / 1023 = 0.004887 volt =4.88millivolt

One binary digit changes when 4.88volt changes takes place

Image's Step Size is 1.25 volt

*******************************************************************************************************

Go Here for Part 2

Attepmt to Accessing Keyboad Up and down Key by C programm for a project

Attepmt to Accessing Keyboad Up and down Key by C programm for a project

Switch Bounce Tutorials

Switch Bounce

Switch Bounce Tutorials

Switch Bounce

16 Bit Event Counter & Displaying on LCD1

16 Bit Event Counter & Displaying on LCD1

Design of Digital Voltmeter By using Micro-controller Part 2

Design of Digital Voltmeter By using Micro-controller Part 2

Transformer Configuration in Proteus

Setting up A Transformer in Proteus

Transformer Configuration in Proteus

Setting up A Transformer in Proteus

Design of Digital Voltmeter By using Microcontroller

calculation of Vpeak

Image's Step Size is 1.25 volt

*******************************************************************************************************
Go Here for Part 2

Design of Digital Voltmeter By using Microcontroller

calculation of Vpeak

Image's Step Size is 1.25 volt

*******************************************************************************************************

Go Here for Part 2

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Switch Bounce

Switch Bounce

Setting up A Transformer in Proteus

Setting up A Transformer in Proteus

calculation of Vpeak

Image's Step Size is 1.25 volt*******************************************************************************************************Go Here for Part 2

calculation of Vpeak

Image's Step Size is 1.25 volt ******************************************************************************************************* Go Here for Part 2

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RECENT COMMENTS

Subscribe Via Email

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Image's Step Size is 1.25 volt

*******************************************************************************************************
Go Here for Part 2

Image's Step Size is 1.25 volt

*******************************************************************************************************

Go Here for Part 2