[SOLVED] line follower robot using stm 32 in keil u version with explanation

#define  RCC_APB2ENR	( * ((volatile unsigned long*) 0x40021018))
#define GPIOA_CRL		( * ((volatile unsigned long*) 0x40010800))
#define GPIOA_CRH		( * ((volatile unsigned long*) 0x40010804))
#define GPIOA_ODR		( * ((volatile unsigned long*) 0x4001080C))
#define GPIOB_CRL		( * ((volatile unsigned long*) 0x40010C00))
#define GPIOB_CRH		( * ((volatile unsigned long*) 0x40010C04))
#define GPIOB_ODR		( * ((volatile unsigned long*) 0x40010C0C))
#define GPIOC_CRL		( * ((volatile unsigned long*) 0x40011000))
#define GPIOC_CRH		( * ((volatile unsigned long*) 0x40011004))
#define GPIOC_ODR		( * ((volatile unsigned long*) 0x4001100C))


void Delay(void)
	{
	volatile unsigned int i;
	for (i = 0;  i < 325000; i++)  //DELAY OF 1 SECOND
		{
		
		}

	}

void SystemInit(void)
	{
	}

int main(void)
	{
	RCC_APB2ENR |= 0x00000018; 
    volatile unsigned short k;
	GPIOC_CRH &=0x11111111;
	GPIOC_CRL &=0x11111111;
	GPIOA_CRH &=0x11111111;
	GPIOB_CRH &=0x11111111;
	volatile unsigned int A =0x0000;	
	volatile unsigned int B =0x8000;	
	volatile unsigned int C =0x2000;	
	volatile unsigned int D =0x0800;    
	volatile unsigned int E =0x0200;	
	volatile unsigned int F =0x0080;	
	volatile unsigned int G =0x0020;	
	volatile unsigned int H =0x0008;	
	volatile unsigned int I =0x0002;	
	



	 while(1)
	  {
		
		 for(k=1;k<17;k++)
		  {
			Delay();
			Delay();

			if(k>=1 && k<=4)
			 {
			  GPIOA_ODR =A;
			  GPIOB_ODR =A;
			 
			 if(k==1)
			   {
				GPIOC_ODR =B;
			   }
			  
			  else if(k==2)
       		   {
				GPIOC_ODR =C;
			   }
			  
			  else if(k==3)
			   {
				GPIOC_ODR =D;
			   }
			  
			  else
			   {
			    GPIOC_ODR =E;
			   } 

			 }
             
			 if(k>=5 && k<=8)
			 {
			  GPIOC_ODR =A;
			  GPIOB_ODR =A;
			  

			  if(k==5)
			   {
				GPIOA_ODR =B;
			   }
			  
			  else if(k==6)
       		   {
				GPIOA_ODR =C;
			   }
			  
			  else if(k==7)
			   {
				GPIOA_ODR =D;
			   }
			  
			  else
			   {
			    GPIOA_ODR =E;
			   } 

			 }
			 if(k>=9 && k<=12)
			 {
			  GPIOA_ODR =A;
			  GPIOB_ODR =A;
			  


			  if(k==9)
			   {
				GPIOC_ODR =F;
			   }
			  
			  else if(k==10)
       		   {
				GPIOC_ODR =G;
			   }
			  
			  else if(k==11)
			   {
				GPIOC_ODR =H;
			   }
			  
			  else
			   {
			    GPIOC_ODR =I;
			   } 

			 }

			 if(k>=13 && k<=16)
			 {
			  GPIOA_ODR =A;
			  GPIOC_ODR =A;
			  

			  if(k==13)
			   {
				GPIOB_ODR =B;
			   }
			  
			  else if(k==14)
       		   {
				GPIOB_ODR =C;
			   }
			  
			  else if(k==15)
			   {
				GPIOB_ODR =D;
			   }
			  
			  else
			   {
			    GPIOB_ODR =E;
			   } 

			 }



		  }
		 }

	   }

#include "main.h"
#include "PWM.h"

void PWM_Init(void)
{
	RCC_APB2ENR |= 0x00000804;	//enable clock to GPIO port A and Timer 1
	GPIOA_CRH &= 0xFFFFF000;	//clear previous config for port A pin 8,9,10
	GPIOA_CRH |= 0x00000999;	//config port A pin 8,9,10 as 10Mhz push pull alternate purpose output.
	TIM1_CR1 = 0x0080;
	TIM1_CNT = 0;
	TIM1_PSC = 7;
	TIM1_ARR = (20000-1);
	TIM1_CCMR1 = 0x6868;
	TIM1_CCMR2 = 0x0068;
	TIM1_CCER = 0x0111;
	TIM1_CCR1 = 1000;
	TIM1_CCR2 = 1000;
	TIM1_CCR3 = 1000;
	TIM1_EGR = 0x0001;
	TIM1_BDTR = 0x8000;
	TIM1_CR1 |= 1;
}

void PWM_Ch1_drive_motor(const uint16_t PERIOD)
{
	if((PERIOD>=10)&&(PERIOD<=19950))
		{
	H	TIM1_CCR1 = PERIOD;
		}
	else if(PERIOD<10)
		{
		TIM1_CCR1=10;
		}
	else
		{
		TIM1_CCR1=19950;
		}	

	
}