#include <stm32f10x.h>
#include <delay.h>
#include <stm32f10x_gpio.h>
#include <stm32f10x_rcc.h>
#include <stm32f10x_i2c.h>
#include <string.h>

#define I2Cx					I2C2
#define I2C_GPIO		  GPIOB
#define I2C_GPIO_SDA	GPIO_Pin_11
#define I2C_GPIO_SCL	GPIO_Pin_10

#define LED				GPIO_Pin_13
#define LEDport 			GPIOC

void i2c_init(void);
void i2c_start(void);
void i2c_stop(void);
void i2c_address_direction(uint8_t address, uint8_t direction);
void i2c_transmit(uint8_t byte);
uint8_t i2c_receive_ack(void);
uint8_t i2c_receive_nack(void);
void i2c_write(uint8_t address, uint8_t data);
void i2c_read(uint8_t address, uint8_t* data);

#define SLAVE_ADDRESS		0x68	//when ADO is low, 0x69 when ADO is high
#define PWR_MGMT_R			0x6B			//config. register
#define AccelX_H_R				0x3B		//accel X axis High bit register
#define AccelX_L_R   	    0x3C		//accel X axis low bit register
//#define AccelZ_R     	  0x3D

char displayString[7];
uint8_t dataStorage[4];

void blinkOnBoardLed(uint8_t a);



uint8_t Accel_X_data;
uint8_t receivedByte1;	//msb
uint8_t receivedByte2;	//lsb
uint8_t receivedByte3;	//xlsb
uint32_t full20BitData;
uint32_t register_data;


int main(void)
{
	 
	
	//1. Configure pins B11 & B10 as alternate function, output and pull up
		RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
		GPIO_InitTypeDef GPIO_Init_struct = {
			.GPIO_Pin =  I2C_GPIO_SDA | I2C_GPIO_SCL, 
			.GPIO_Mode = GPIO_Mode_AF_OD,
			.GPIO_Speed = GPIO_Speed_2MHz};
		GPIO_Init(I2C_GPIO, &GPIO_Init_struct);
			
			//1b. initialize an output pin for the onboard Led
			GPIO_InitTypeDef GPIO_Init_struct_b = {
				.GPIO_Pin =  LED,
				.GPIO_Mode = GPIO_Mode_Out_PP,
				.GPIO_Speed = GPIO_Speed_50MHz};
			GPIO_Init(LEDport, &GPIO_Init_struct_b);
				
		
	//2. initialize i2c on pins B11 and B10
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2,ENABLE);
		I2C_InitTypeDef I2C_Init_struct = {
			.I2C_ClockSpeed = 100000,
			.I2C_Mode = I2C_Mode_I2C,
			.I2C_DutyCycle = I2C_DutyCycle_2,
			.I2C_OwnAddress1 = 0x00,
			.I2C_Ack = I2C_Ack_Disable,
			.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit};
		I2C_Init(I2Cx, &I2C_Init_struct);
		I2C_Cmd(I2Cx, ENABLE);
			
		
	DelayInit();
		
	while(1){
    strcpy(displayString, "0");
		
		//start
	i2c_start();
		//send slave address and recieve ack
	i2c_address_direction(SLAVE_ADDRESS<<1, I2C_Direction_Transmitter);
		//send register address and recieve ack
	i2c_transmit(PWR_MGMT_R);
		//send data to write to RA (register address)
	i2c_transmit(0x00);
		//Nack and stop
		i2c_stop();

	blinkOnBoardLed(3);
	strcpy(displayString, "1");
	DelayMs(1000);
	
			//start
	i2c_start();
		//send slave address and recieve ack
	i2c_address_direction(SLAVE_ADDRESS<<1, I2C_Direction_Transmitter);
		//send register address to read from and recieve ack
	i2c_transmit(AccelX_L_R );
		//start again
							
								// Generate start condition
					I2C_GenerateSTART(I2Cx, ENABLE);
					while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
			
		//send slave address to receive
	i2c_address_direction(SLAVE_ADDRESS<<1, I2C_Direction_Receiver);
					
			// Disable ACK of received data
	I2C_AcknowledgeConfig(I2Cx, DISABLE);
		// Wait for I2C EV7
	// It means that the data has been received in I2C data register
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));
	
	Accel_X_data = I2C_ReceiveData(I2Cx);
		//Nack and stop
		i2c_stop();
	
	
	blinkOnBoardLed(5);
	strcpy(displayString, "2");
	DelayMs(2000);	
	
		
		
		
		

	}
}



void i2c_start()
{
	// Wait until I2Cx is not busy anymore
	while (I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));

	// Generate start condition
	I2C_GenerateSTART(I2Cx, ENABLE);

	// Wait for I2C EV5.
	// It means that the start condition has been correctly released
	// on the I2C bus (the bus is free, no other devices is communicating))
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
}

void i2c_stop()
{
	
	// Generate I2C stop condition
	I2C_GenerateSTOP(I2Cx, ENABLE);
	// Wait until I2C stop condition is finished
	while (I2C_GetFlagStatus(I2Cx, I2C_FLAG_STOPF));
}

void i2c_address_direction(uint8_t address, uint8_t direction)
{
	// Send slave address
	I2C_Send7bitAddress(I2Cx, address, direction);

	// Wait for I2C EV6
	// It means that a slave acknowledges his address
	if (direction == I2C_Direction_Transmitter)
	{
		while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
	}
	else if (direction == I2C_Direction_Receiver)
	{
		while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
	}
}

void i2c_transmit(uint8_t byte)
{
	// Send data byte
	I2C_SendData(I2Cx, byte);
	// Wait for I2C EV8_2.
	// It means that the data has been physically shifted out and
	// output on the bus)
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
}

uint8_t i2c_receive_ack()
{
	// Enable ACK of received data
	I2C_AcknowledgeConfig(I2Cx, ENABLE);
	// Wait for I2C EV7
	// It means that the data has been received in I2C data register
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));

	// Read and return data byte from I2C data register
	return I2C_ReceiveData(I2Cx);
}

uint8_t i2c_receive_nack()
{
	// Disable ACK of received data
	I2C_AcknowledgeConfig(I2Cx, DISABLE);
	// Wait for I2C EV7
	// It means that the data has been received in I2C data register
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));

	// Read and return data byte from I2C data register
	return I2C_ReceiveData(I2Cx);
}

void i2c_write(uint8_t address, uint8_t data)
{
	i2c_start();
	i2c_address_direction(address << 1, I2C_Direction_Transmitter);
	i2c_transmit(data);
	i2c_stop();
}

void i2c_read(uint8_t address, uint8_t* data)
{
	i2c_start();
	i2c_address_direction(address << 1, I2C_Direction_Receiver);
	*data = i2c_receive_nack();
	i2c_stop();
}

void i2c_burst_read(uint8_t address, uint8_t* data1, uint8_t* data2, uint8_t* data3){
	i2c_start();
	i2c_address_direction(address<<1, I2C_Direction_Receiver);
	*data1 = i2c_receive_ack();
	*data2 = i2c_receive_ack();
	*data3 = i2c_receive_nack();

	i2c_stop();
}

void blinkOnBoardLed(uint8_t a){
	for(int i = 0; i < a; i++){		
		DelayMs(100);
		GPIO_SetBits(LEDport, LED);
		DelayMs(100);
		GPIO_ResetBits(LEDport, LED);
	}
}