#include <stdint.h>

#define RCC_BASE  0x40021000UL
#define RCC_IOPENR  (*(volatile uint32_t*)(RCC_BASE + 0x34))

#define GPIOA_BASE  0x50000000UL
#define GPIOA_MODER (*(volatile uint32_t*)(GPIOA_BASE + 0x00))

#define GPIOB_BASE 0x50000400UL
#define GPIOB_MODER (*(volatile uint32_t*)(GPIOB_BASE + 0x00))

#define RCC_APBENR2 (*(volatile uint32_t*)(RCC_BASE + 0x40))
#define ADCEN (1<<20)

#define ADC_BASE 0x40012400UL
#define ADC_CR  (*(volatile uint32_t*)(ADC_BASE + 0x08))
#define ADC_ISR  (*(volatile uint32_t*)(ADC_BASE + 0x00))
#define ADC_CHSELR  (*(volatile uint32_t*)(ADC_BASE + 0x28))
#define ADC_DR  (*(volatile uint32_t*)(ADC_BASE + 0x40))


#define ADEN (1<<0) // bit 0 of ADC_CR 0 - disable ADC, 1- enable ADC
#define ADDIS (1<<1) // bit 1 of ADC_CR 0- No ADDIS command, 1- disable ADC
#define ADCAL (1<<31) //bit 31 of ADC_CR 0-cal complete, 1-to calibrate ADC
#define ADSTART (1<<2) //bit 2 of ADC_CR 0-No ADC, 1-to start ADC
#define ADRDY (1<<0) //bit 0 of ADC_ISR 0-ADC not ready, 1-ADC is ready
#define EOC (1<<2) //bit 2 of ADC_ISR 0-channel conversion not complete, 1-completed

#define PA1 (1<<1)

#define RCC_APBENR1 (*(volatile uint32_t*)(RCC_BASE + 0x3C))
#define TIM3EN (1<<1)

#define TIM3_BASE   0x40000400UL

#define TIM3_CR1    (*(volatile uint32_t*)(TIM3_BASE + 0x00))
#define TIM3_CCMR1  (*(volatile uint32_t*)(TIM3_BASE + 0x18))
#define TIM3_CCER   (*(volatile uint32_t*)(TIM3_BASE + 0x20))
#define TIM3_PSC    (*(volatile uint32_t*)(TIM3_BASE + 0x28))
#define TIM3_ARR    (*(volatile uint32_t*)(TIM3_BASE + 0x2C))
#define TIM3_CCR1   (*(volatile uint32_t*)(TIM3_BASE + 0x34))
#define TIM3_EGR    (*(volatile uint32_t*)(TIM3_BASE + 0x14))

#define GPIOB_AFRL (*(volatile uint32_t*)(GPIOB_BASE + 0x20))

void ADC_disable(){

  if (ADC_CR & ADEN){
   ADC_CR |= ADDIS;
   while(ADC_CR & ADEN);
  }
}

void Start_Cal(){

  ADC_CR |= ADCAL;
  while(ADC_CR & ADCAL);

}

void Enable_ADC(){

ADC_ISR |= ADRDY;
ADC_CR |= ADEN;
while (!(ADC_ISR & ADRDY ));

}

void Sel_Chnl(){

ADC_CHSELR = PA1 ;

}

void Set_PSC_ARR(){

TIM3_PSC = 11;
TIM3_ARR = 4095;
TIM3_EGR |= (1<<0);

}

void PWM_Confg(){

TIM3_CCMR1 &= ~(7<<4);
TIM3_CCMR1 |= (6<<4);
TIM3_CCMR1 |= (1<<3);

TIM3_CCER |= (1<<0);
TIM3_CR1 |= (1<<7);
TIM3_CR1 |= (1<<0);

}





int main(){

uint32_t adc_value =0;
RCC_IOPENR |= ((1<<0)|(1<<1));

GPIOA_MODER &= ~(3<<(1*2));
GPIOA_MODER |= (3<<(1*2));

GPIOB_MODER &= ~(3<<(4*2));
GPIOB_MODER |= (2<<(4*2));

RCC_APBENR2 |= ADCEN ;

RCC_APBENR1 |= TIM3EN ;

GPIOB_AFRL &= ~ (15<<16);
GPIOB_AFRL |= (1<<16);

// ADC conversion steps

ADC_disable();
Start_Cal();
Enable_ADC();
Sel_Chnl();

// PWM GENERATION STEPS

Set_PSC_ARR();
PWM_Confg();


while(1){

  ADC_CR |= ADSTART;
  while(!(ADC_ISR & EOC));
  adc_value = ADC_DR;
  TIM3_CCR1 = adc_value;
}

}