/* ----------------------------- */
/*     I2C Low Level Routinen    */
/* ----------------------------- */

/* -------------------- Standard Include Files --------------------- */
#include <stdbool.h>
#include <stdint.h>

/* -------------------- Zusätzliche Include Files ------------------ */
#include "i2c_basic.h"


// ---------------------------------------------------------------
// Initialisiere den I2C Bus
// ---------------------------------------------------------------
void I2C1_Init()
{
    GPIO_InitTypeDef GPIO_InitStruct;       // Port Init Struct
    I2C_InitTypeDef I2C_InitStruct;         // I2C Init Struct

    // Peripherie Takt einschalten I2C3: PB6 (I2C1 SCL) und PB7 (I2C1_SDA)
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    // Port mit SCL/SCA einrichten
    GPIO_InitStruct.GPIO_Pin   = I2C_SCL_PIN | I2C_SDA_PIN;
    GPIO_InitStruct.GPIO_Mode  = GPIO_Mode_AF_OD;            // Pins als Alternate Function einstellen
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;           // IO Speed, nicht Baudrate, 2 Mhz reicht

    GPIO_Init(I2C_SCL_PORT, &GPIO_InitStruct);

    // Struktur Parameter fuer I2C setzen
    I2C_StructInit(&I2C_InitStruct);                                        // Rücksetzen auf Default
    I2C_InitStruct.I2C_ClockSpeed           = I2C_SPEED;                    // 100 khz Busfrequenz
    I2C_InitStruct.I2C_Mode                 = I2C_Mode_I2C;                 // Normaler I2C Mode
    I2C_InitStruct.I2C_DutyCycle            = I2C_DutyCycle_2;              // 50:50 Duty Cycle
    I2C_InitStruct.I2C_OwnAddress1          = 0x00;                         // Dummy Adresse
    I2C_InitStruct.I2C_Ack                  = I2C_Ack_Enable;               // ACK senden
    I2C_InitStruct.I2C_AcknowledgedAddress  = I2C_AcknowledgedAddress_7bit; // 7 Bit Adressierung

    // I2C3 mit den obigen Parametern konfigurieren
    I2C_Init(I2Cx, &I2C_InitStruct);

    // I2C einschalten
    I2C_Cmd(I2Cx, ENABLE);
}


void I2C1_Disable() {
    I2C_Cmd(I2Cx, DISABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, DISABLE);
}

/* ----- Erzeuge Start Bedingung ------ */
ErrorStatus i2c_start()
{
   int timeout = I2C_TIMEOUT;

   I2C_GenerateSTART(I2Cx, ENABLE);
   /* Warte auf I2C EV5. Bus frei, Start akzeptiert */
   while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT))
   {
       if (!(--timeout)) {
            return ERROR;
       }
   }
   return SUCCESS;
}

/* --------- Erzeuge Stop Bedingung ------- */
void i2c_stop()
{
    I2C_GenerateSTOP(I2Cx, ENABLE);
    // while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));
}

/* ---------- Adressiere den Slave --------
   Write: I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED
   Read:  I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED
*/
ErrorStatus i2c_address_direction(uint8_t address, uint8_t direction)
{
    unsigned int timeout = I2C_TIMEOUT;

    /* Adressiere den Slave mit Datenrichtung */
    I2C_Send7bitAddress(I2Cx, address, direction);
    /* Warte auf I2C EV6, Slave hat seine Adressierung akzeptiert */
    if (direction == I2C_Direction_Transmitter)  {
        while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)) {
            if (!(--timeout)) {
               return ERROR;
            }
        }
    }
    if (direction == I2C_Direction_Receiver)  {
        while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)) {
            if (!(--timeout)) {
               return ERROR;
            }
        }
    }

    return SUCCESS;
}

/* ------- Uebertrage 1 Byte an Slave ----- */
ErrorStatus i2c_write(uint8_t byte)
{
    unsigned int timeout = I2C_TIMEOUT;

    I2C_SendData(I2Cx, byte);
    /* Warte auf Ev8_2, Datum wurde heraus geschoben */
    while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED))   {
        if (!(--timeout))
            return ERROR;
    }
    return SUCCESS;
}

/*
    Ein Byte vom Slave lesen und mit ACK bestätigen, dass noch ein
    weiteres Byte angefordert wird
*/
uint8_t i2c_receive_ack()
{
    I2C_AcknowledgeConfig(I2Cx, ENABLE);
    /* Warte fuer I2C EV7, d.h. Daten sind im Register empfangen worden. */
    while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));
    return(I2C_ReceiveData(I2Cx));
}

/*
    Ein Byte vom Slave lesen und mit NACK bestätigen, dass KEIN
    weiteres Byte angefordert wird.
*/
uint8_t i2c_receive_nack()
{
    I2C_AcknowledgeConfig(I2Cx, DISABLE);
    // Warte fuer EV7 = Daten sind empfangen worden
    while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));

    I2C_GenerateSTOP(I2Cx, ENABLE);
    while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));

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