Write an application to and demonstrate the change in BeagleBoard/ ARM Cortex A5 /Microprocessor /CPU frequency or square wave of programmable frequency

Write an application to and demonstrate the change in BeagleBoard/ ARM Cortex A5 /Microprocessor /CPU frequency or square wave of programmable frequency

 

#include<stdlib.h> //System() Function
#include<signal.h> //signal Handler for CNTR-C
#include<iostream>  //cout , cin
#include<string>    //string 
#include<conio.h>

using namespace std;
void delay(int num);  

int main()
{
int option;
string frq;
string command;

while(1)
        {
                                                                                
cout <<  "\n1.  Press 1 to set the Beagle Board CPU Frequency\n";               
cout <<  "2.  Press 2 to get the current CPU Frequency\n";                      
cout <<  "3.  Press 3 or CNTR-Z to exit\n";                                     
cin > >  option;                                                                  
                                                                                
switch(option)                                                                  
        {                                                                       
        case 1:                                                                 
                cout << "Please Enter the frequency in range 100-1000 (MHz)\n"; 
                cin > >  frq;                                                     
                command="cpufreq-set -f "+frq+"MHz";                            
                                                                                
                if(system(command.c_str()))                                     
                cout << "\nCannot Set the Frequency. Make sure logged in as ROOT\n";
                                                                                
                                                                                
                                                                                
        case 2:                                                                 
                                                           
                while(!kbhit())                                              
                {                                                               
                        cout << "Press any key to go Back in main menu \n";         
                                                                                
                        system("cpufreq-info | tail -2");                       
                        delay(50000);                                           
                }                                                               
        break;                                                                  
        case 3:                                                                 
                exit(0);                                                        
                                                                                
        }                                                                       
        }                                                                       
}                                                                               
void delay(int num)                                                             
{                                                                               
        int i,j;                                                                
        for(i=0; i < num;i++)                                                      
                for(j=0; j < 1275;j++);                                            
} 
OUTPUT:-
root@beaglebone:/home/debian# g++ -o cpu cpu.cpp
Cannot create temporary file in ./: Read-only file system
Aborted
root@beaglebone:/home/debian# ./cpu

1.  Press 1 to set the Beagle Board CPU Frequency
2.  Press 2 to get the current CPU Frequency
3.  Press 3 or CNTR-Z to exit
2
Press CNTR+C to Back in main menu 
  current CPU frequency is 300 MHz (asserted by call to hardware).
  cpufreq stats: 300 MHz:70.37%, 600 MHz:16.56%, 800 MHz:0.09%, 1000 MHz:12.98%)
Press CNTR+C to Back in main menu 
  current CPU frequency is 300 MHz (asserted by call to hardware).
  cpufreq stats: 300 MHz:70.40%, 600 MHz:16.55%, 800 MHz:0.09%, 1000 MHz:12.96%)
^C
1.  Press 1 to set the Beagle Board CPU Frequency
2.  Press 2 to get the current CPU Frequency
3.  Press 3 or CNTR-Z to exit
1
Please Enter the frequency in range 100-1000 (MHz)
600
Press CNTR+C to Back in main menu 
  current CPU frequency is 600 MHz (asserted by call to hardware).              
  cpufreq stats: 300 MHz:70.62%, 600 MHz:16.42%, 800 MHz:0.09%, 1000 MHz:12.87%)
Press CNTR+C to Back in main menu                                               
  current CPU frequency is 600 MHz (asserted by call to hardware).              
  cpufreq stats: 300 MHz:70.58%, 600 MHz:16.47%, 800 MHz:0.09%, 1000 MHz:12.86%)
^C                                                                              
1.  Press 1 to set the Beagle Board CPU Frequency                               
2.  Press 2 to get the current CPU Frequency                                    
3.  Press 3 or CNTR-Z to exit                                                   
3                                                                               
root@beaglebone:/home/debian# ^C                                                
root@beaglebone:/home/debian#