#include "stm32f103xb.h"

  void I2C_PWR();
  void I2C_read();
  void Delay();
  void PWM_Init();
  volatile uint8_t Address_Read;
  int16_t data_x,data_y,data_z;
  #define delay_time 10
  void init() {
   RCC->APB2ENR |= RCC_APB2ENR_IOPBEN|RCC_APB2ENR_IOPAEN | RCC_APB2ENR_AFIOEN;
   RCC->APB1ENR |= RCC_APB1ENR_I2C2EN;
   GPIOB->CRH = 0x4444FF44; // AF open drain
   GPIOB->CRL = 0x4444444B; // PB0 alt for pwm
   GPIOA->CRL = 0x44444333; // LED PA0 output G.P. push-pull, PA1 & PA2 outputs for motor
   I2C2->CR1 &= ~ I2C_CR1_PE;
   I2C2->CR1 |= (1 << 15); // reset the I2C
   I2C2->CR1 &= ~(1 << 15); // Normal operation
   I2C2->CR2 |= 8; // I2C APB clock frequency
   I2C2->CCR = 40; // I2C Standard Mode
   I2C2->TRISE = 9;
   I2C2->CR1 |= I2C_CR1_PE;
   }
  void motorControl(int16_t gyroData) {
         // PA1 and PA2 are used for motor direction control
         if (gyroData > 0) {
             // Rotate clockwise
             GPIOA->ODR &= ~GPIO_ODR_ODR2; // PA2 = 0
             GPIOA->ODR |= GPIO_ODR_ODR1;  // PA1 = 1
         } else if (gyroData < 0) {
             // Rotate counter-clockwise
             GPIOA->ODR |= GPIO_ODR_ODR2;   // PA2 = 1
             GPIOA->ODR &= ~GPIO_ODR_ODR1;  // PA1 = 0
             gyroData = gyroData * -1;
         }
         TIM3->CCR3= gyroData;
     }
  int main(){
        init();
        PWM_Init();
        I2C_PWR();
        while(1){
           I2C_read();
           motorControl(data_x);
           if(data_x>0){
	           GPIOA->ODR|=(1<<0);
           }
          else{
        	  GPIOA->ODR&=~(1<<0);
          }

  }
  }
  void PWM_Init() {
      RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
      TIM3->CCER |= (1 << 8);
      TIM3->CCMR2 |= 0b1101000;
      TIM3->CR1 =0b1000001;
      TIM3->PSC = 0;  // Set the prescaler value
      TIM3->ARR = 4000;  // Set the auto-reload value
      TIM3->EGR=1;
      TIM3->CR1 |= 0x01;   // start counting
  }
  void I2C_PWR(){
     while(I2C2->SR2 & I2C_SR2_BUSY); // check if the I2C is busy
     I2C2->CR1|=I2C_CR1_START; // send start bit
     while(!(I2C2->CR1 & I2C_SR1_SB)); // check start bit
     Delay(); // small delay inserted after the start bit for timing
     I2C2->DR = 0x68 << 1 ; // send address
     while (!(I2C2->SR1 & I2C_SR1_ADDR));// check for address, skip in debugging
     Address_Read = I2C2->SR1 | I2C2->SR2;// read SR1 and SR2 to clear the ADDR bit
     while(!(I2C2->SR1 & (I2C_SR1_TXE))); // I2C ready for next byte
     I2C2->DR=0x6B; // send address of pwr register
     while(!(I2C2->SR1 & (I2C_SR1_TXE))); // I2C ready for next byte
     I2C2->DR=0; // send 0
     while(!(I2C2->SR1 & (I2C_SR1_BTF))); // check last byte transmission ended
     I2C2->CR1|=I2C_CR1_STOP; // Stop I2C
  }
  void I2C_read(){
     while(I2C2->SR2 & I2C_SR2_BUSY);
     I2C2->CR1|=I2C_CR1_START; // send start bit
     while(!(I2C2->CR1 & I2C_SR1_SB)); // check start bit
     Delay(); // small delay inserted after the start bit for timing
     I2C2->DR = (0x68 << 1) ; // send address
     while (!(I2C2->SR1 & I2C_SR1_ADDR));// check for address, skip in debugging
     Address_Read = I2C2->SR1 | I2C2->SR2;// read SR1 and SR2 to clear the ADDR bit
     while(!(I2C2->SR1 & (I2C_SR1_TXE))); // I2C ready for next byte
     I2C2->DR=59; // send address of a_x register
     while(!(I2C2->SR1 & (I2C_SR1_BTF))); // check last byte transmission ended
     I2C2->CR1|=I2C_CR1_START|I2C_CR1_ACK; // double start, enable acknowledgment
     while(!(I2C2->CR1 & I2C_SR1_SB)); // check start bit
     Delay(); // small delay inserted after the start bit for timing
     I2C2->DR = (0x68 << 1)|1 ; // send address
     while(!(I2C2->SR1 & (I2C_SR1_ADDR)));// check for address, skip in debugging}
     Address_Read = I2C2->SR1 | I2C2->SR2;// read SR1 and SR2 to clear the ADDR bit
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_x= I2C2->DR;
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_x= (data_x<<8)|I2C2->DR;
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_y= I2C2->DR;
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_y= (data_y<<8)|I2C2->DR;
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_z= I2C2->DR;
     I2C2->CR1 |= (1 << 9); // Stop I2C before the end of the last byte
     I2C2->CR1 &= ~I2C_CR1_ACK; // Stop ACK
     while(!(I2C2->SR1 & I2C_SR1_RXNE));// check for data received, skip in debugging
     data_z= (data_z<<8)|I2C2->DR;
     }
     void Delay(){
     for( int i=0;i<=delay_time;i++);
     }