/**
  MSSP Generated Driver File

  @Company
    Microchip Technology Inc.

  @File Name
    i2c.c

  @Summary
    This is the generated header file for the MSSP driver using PIC10 / PIC12 / PIC16 / PIC18 MCUs

  @Description
    This header file provides APIs for driver for I2C.
    Generation Information :
        Product Revision  :  PIC10 / PIC12 / PIC16 / PIC18 MCUs - 1.77
        Device            :  PIC16F1769
        Driver Version    :  2.02
    The generated drivers are tested against the following:
        Compiler          :  XC8 2.05 and above
        MPLAB 	          :  MPLAB X 5.20	
*/

/*
    (c) 2018 Microchip Technology Inc. and its subsidiaries. 
    
    Subject to your compliance with these terms, you may use Microchip software and any 
    derivatives exclusively with Microchip products. It is your responsibility to comply with third party 
    license terms applicable to your use of third party software (including open source software) that 
    may accompany Microchip software.
    
    THIS SOFTWARE IS SUPPLIED BY MICROCHIP "AS IS". NO WARRANTIES, WHETHER 
    EXPRESS, IMPLIED OR STATUTORY, APPLY TO THIS SOFTWARE, INCLUDING ANY 
    IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY, AND FITNESS 
    FOR A PARTICULAR PURPOSE.
    
    IN NO EVENT WILL MICROCHIP BE LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, 
    INCIDENTAL OR CONSEQUENTIAL LOSS, DAMAGE, COST OR EXPENSE OF ANY KIND 
    WHATSOEVER RELATED TO THE SOFTWARE, HOWEVER CAUSED, EVEN IF MICROCHIP 
    HAS BEEN ADVISED OF THE POSSIBILITY OR THE DAMAGES ARE FORESEEABLE. TO 
    THE FULLEST EXTENT ALLOWED BY LAW, MICROCHIP'S TOTAL LIABILITY ON ALL 
    CLAIMS IN ANY WAY RELATED TO THIS SOFTWARE WILL NOT EXCEED THE AMOUNT 
    OF FEES, IF ANY, THAT YOU HAVE PAID DIRECTLY TO MICROCHIP FOR THIS 
    SOFTWARE.
*/

/**
  Section: Included Files
*/

#include "i2c.h"

/**
  I2C Driver Queue Status Type

  @Summary
    Defines the type used for the transaction queue status.

  @Description
    This defines type used to keep track of the queue status.
 */

typedef union
{
    struct
    {
            uint8_t full:1;
            uint8_t empty:1;
            uint8_t reserved:6;
    }s;
    uint8_t status;
}I2C_TR_QUEUE_STATUS;

/**
  I2C Driver Queue Entry Type

  @Summary
    Defines the object used for an entry in the i2c queue items.

  @Description
    This defines the object in the i2c queue. Each entry is a composed
    of a list of TRBs, the number of the TRBs and the status of the
    currently processed TRB.
 */
typedef struct
{
    uint8_t                             count;          // a count of trb's in the trb list
    I2C_TRANSACTION_REQUEST_BLOCK *ptrb_list;     // pointer to the trb list
    I2C_MESSAGE_STATUS            *pTrFlag;       // set with the error of the last trb sent.
                                                        // if all trb's are sent successfully,
                                                        // then this is I2C_MESSAGE_COMPLETE
} I2C_TR_QUEUE_ENTRY;

/**
  I2C Master Driver Object Type

  @Summary
    Defines the object that manages the i2c master.

  @Description
    This defines the object that manages the sending and receiving of
    i2c master transactions.
  */

typedef struct
{
    /* Read/Write Queue */
    I2C_TR_QUEUE_ENTRY          *pTrTail;       // tail of the queue
    I2C_TR_QUEUE_ENTRY          *pTrHead;       // head of the queue
    I2C_TR_QUEUE_STATUS         trStatus;       // status of the last transaction
    uint8_t                         i2cDoneFlag;    // flag to indicate the current
                                                    // transaction is done
    uint8_t                         i2cErrors;      // keeps track of errors


} I2C_OBJECT ;

/**
  I2C Master Driver State Enumeration

  @Summary
    Defines the different states of the i2c master.

  @Description
    This defines the different states that the i2c master
    used to process transactions on the i2c bus.
*/

typedef enum
{
    S_MASTER_IDLE,
    S_MASTER_RESTART,
    S_MASTER_SEND_ADDR,
    S_MASTER_SEND_DATA,
    S_MASTER_SEND_STOP,
    S_MASTER_ACK_ADDR,
    S_MASTER_RCV_DATA,
    S_MASTER_RCV_STOP,
    S_MASTER_ACK_RCV_DATA,
    S_MASTER_NOACK_STOP,
    S_MASTER_SEND_ADDR_10BIT_LSB,
    S_MASTER_10BIT_RESTART,
    
} I2C_MASTER_STATES;

/**
 Section: Macro Definitions
*/

/* defined for I2C */

#ifndef I2C_CONFIG_TR_QUEUE_LENGTH
        #define I2C_CONFIG_TR_QUEUE_LENGTH 1
#endif

#define I2C_TRANSMIT_REG                       SSP1BUF                 // Defines the transmit register used to send data.
#define I2C_RECEIVE_REG                        SSP1BUF                 // Defines the receive register used to receive data.

// The following control bits are used in the I2C state machine to manage
// the I2C module and determine next states.
#define I2C_WRITE_COLLISION_STATUS_BIT         SSP1CON1bits.WCOL     // Defines the write collision status bit.
#define I2C_MODE_SELECT_BITS                   SSP1CON1bits.SSPM     // I2C Master Mode control bit.
#define I2C_MASTER_ENABLE_CONTROL_BITS         SSP1CON1bits.SSPEN    // I2C port enable control bit.

#define I2C_START_CONDITION_ENABLE_BIT         SSP1CON2bits.SEN      // I2C START control bit.
#define I2C_REPEAT_START_CONDITION_ENABLE_BIT  SSP1CON2bits.RSEN     // I2C Repeated START control bit.
#define I2C_RECEIVE_ENABLE_BIT                 SSP1CON2bits.RCEN     // I2C Receive enable control bit.
#define I2C_STOP_CONDITION_ENABLE_BIT          SSP1CON2bits.PEN      // I2C STOP control bit.
#define I2C_ACKNOWLEDGE_ENABLE_BIT             SSP1CON2bits.ACKEN    // I2C ACK start control bit.
#define I2C_ACKNOWLEDGE_DATA_BIT               SSP1CON2bits.ACKDT    // I2C ACK data control bit.
#define I2C_ACKNOWLEDGE_STATUS_BIT             SSP1CON2bits.ACKSTAT  // I2C ACK status bit.

#define I2C_7bit    true
/**
 Section: Local Functions
*/

void I2C_FunctionComplete(void);
void I2C_Stop(I2C_MESSAGE_STATUS completion_code);

/**
 Section: Local Variables
*/

static I2C_TR_QUEUE_ENTRY                  i2c_tr_queue[I2C_CONFIG_TR_QUEUE_LENGTH];
static I2C_OBJECT                          i2c_object;
static I2C_MASTER_STATES                   i2c_state = S_MASTER_IDLE;
static uint8_t                             i2c_trb_count = 0;

static I2C_TRANSACTION_REQUEST_BLOCK      *p_i2c_trb_current = NULL;
static volatile I2C_TR_QUEUE_ENTRY         *p_i2c_current = NULL;


/**
  Section: Driver Interface
*/

void I2C_Initialize(void)
{
    i2c_object.pTrHead = i2c_tr_queue;
    i2c_object.pTrTail = i2c_tr_queue;
    i2c_object.trStatus.s.empty = true;
    i2c_object.trStatus.s.full = false;

    i2c_object.i2cErrors = 0;

    // R_nW write_noTX; P stopbit_notdetected; S startbit_notdetected; BF RCinprocess_TXcomplete; SMP Standard Speed; UA dontupdate; CKE disabled; D_nA lastbyte_address; 
    SSP1STAT = 0x80;
    // SSPEN enabled; WCOL no_collision; CKP Idle:Low, Active:High; SSPM FOSC/4_SSPxADD_I2C; SSPOV no_overflow; 
    SSP1CON1 = 0x28;
    // ACKTIM ackseq; SBCDE disabled; BOEN disabled; SCIE disabled; PCIE disabled; DHEN disabled; SDAHT 100ns; AHEN disabled; 
    SSP1CON3 = 0x00;
    // SSP1ADD 19; 
    SSP1ADD = 0x13;
    
    // clear the interrupt flags
    PIR1bits.SSP1IF = 0;
    PIR2bits.BCL1IF = 0;
	
    // enable the interrupts
    PIE1bits.SSP1IE = 1;
    PIE2bits.BCL1IE = 1;
    
}

        
uint8_t I2C_ErrorCountGet(void)
{
    uint8_t ret;

    ret = i2c_object.i2cErrors;
    return ret;
}

void I2C_ISR ( void )
{
  
    static uint8_t  *pi2c_buf_ptr;
    static uint16_t i2c_address         = 0;
    static uint8_t  i2c_bytes_left      = 0;
    static uint8_t  i2c_10bit_address_restart = 0;

    PIR1bits.SSP1IF = 0;
    
    // Check first if there was a collision.
    // If we have a Write Collision, reset and go to idle state */
    if(I2C_WRITE_COLLISION_STATUS_BIT)
    {
        // clear the Write colision
        I2C_WRITE_COLLISION_STATUS_BIT = 0;
        i2c_state = S_MASTER_IDLE;
        *(p_i2c_current->pTrFlag) = I2C_MESSAGE_FAIL;

        // reset the buffer pointer
        p_i2c_current = NULL;

        return;
    }

    /* Handle the correct i2c state */
    switch(i2c_state)
    {
        case S_MASTER_IDLE:    /* In reset state, waiting for data to send */

            if(i2c_object.trStatus.s.empty != true)
            {
                // grab the item pointed by the head
                p_i2c_current     = i2c_object.pTrHead;
                i2c_trb_count     = i2c_object.pTrHead->count;
                p_i2c_trb_current = i2c_object.pTrHead->ptrb_list;

                i2c_object.pTrHead++;

                // check if the end of the array is reached
                if(i2c_object.pTrHead == (i2c_tr_queue + I2C_CONFIG_TR_QUEUE_LENGTH))
                {
                    // adjust to restart at the beginning of the array
                    i2c_object.pTrHead = i2c_tr_queue;
                }

                // since we moved one item to be processed, we know
                // it is not full, so set the full status to false
                i2c_object.trStatus.s.full = false;

                // check if the queue is empty
                if(i2c_object.pTrHead == i2c_object.pTrTail)
                {
                    // it is empty so set the empty status to true
                    i2c_object.trStatus.s.empty = true;
                }

                // send the start condition
                I2C_START_CONDITION_ENABLE_BIT = 1;
                
                // start the i2c request
                i2c_state = S_MASTER_SEND_ADDR;
            }

            break;

        case S_MASTER_RESTART:

            /* check for pending i2c Request */

            // ... trigger a REPEATED START
            I2C_REPEAT_START_CONDITION_ENABLE_BIT = 1;

            // start the i2c request
            i2c_state = S_MASTER_SEND_ADDR;

            break;

        case S_MASTER_SEND_ADDR_10BIT_LSB:

            if(I2C_ACKNOWLEDGE_STATUS_BIT)
            {
                i2c_object.i2cErrors++;
                I2C_Stop(I2C_MESSAGE_ADDRESS_NO_ACK);
            }
            else
            {
                // Remove bit 0 as R/W is never sent here
                I2C_TRANSMIT_REG = (i2c_address >> 1) & 0x00FF;

                // determine the next state, check R/W
                if(i2c_address & 0x01)
                {
                    // if this is a read we must repeat start
                    // the bus to perform a read
                    i2c_state = S_MASTER_10BIT_RESTART;
                }
                else
                {
                    // this is a write continue writing data
                    i2c_state = S_MASTER_SEND_DATA;
                }
            }

            break;

        case S_MASTER_10BIT_RESTART:

            if(I2C_ACKNOWLEDGE_STATUS_BIT)
            {
                i2c_object.i2cErrors++;
                I2C_Stop(I2C_MESSAGE_ADDRESS_NO_ACK);
            }
            else
            {
                // ACK Status is good
                // restart the bus
                I2C_REPEAT_START_CONDITION_ENABLE_BIT = 1;

                // fudge the address so S_MASTER_SEND_ADDR works correctly
                // we only do this on a 10-bit address resend
                i2c_address = 0x00F0 | ((i2c_address >> 8) & 0x0006);

                // set the R/W flag
                i2c_address |= 0x0001;

                // set the address restart flag so we do not change the address
                i2c_10bit_address_restart = 1;

                // Resend the address as a read
                i2c_state = S_MASTER_SEND_ADDR;
            }

            break;

        case S_MASTER_SEND_ADDR:

            /* Start has been sent, send the address byte */

            /* Note: 
                On a 10-bit address resend (done only during a 10-bit
                device read), the original i2c_address was modified in
                S_MASTER_10BIT_RESTART state. So the check if this is
                a 10-bit address will fail and a normal 7-bit address
                is sent with the R/W bit set to read. The flag
                i2c_10bit_address_restart prevents the  address to
                be re-written.
             */
            if(i2c_10bit_address_restart != 1)
            {
                // extract the information for this message
                i2c_address    = p_i2c_trb_current->address;
                pi2c_buf_ptr   = p_i2c_trb_current->pbuffer;
                i2c_bytes_left = p_i2c_trb_current->length;
            }

            // check for 10-bit address
            if(!I2C_7bit && (0x0 != i2c_address))
            {  
                if (0 == i2c_10bit_address_restart)
                {
                    // we have a 10 bit address
                    // send bits<9:8>
                    // mask bit 0 as this is always a write                    
                    I2C_TRANSMIT_REG = 0xF0 | ((i2c_address >> 8) & 0x0006);
                    i2c_state = S_MASTER_SEND_ADDR_10BIT_LSB;
                }
                else
                {
                    // resending address bits<9:8> to trigger read
                    I2C_TRANSMIT_REG = i2c_address;
                    i2c_state = S_MASTER_ACK_ADDR;
                    // reset the flag so the next access is ok
                    i2c_10bit_address_restart = 0;
                }
            }
            else
            {
                // Transmit the address
                I2C_TRANSMIT_REG = i2c_address;
                if(i2c_address & 0x01)
                {
                    // Next state is to wait for address to be acked
                    i2c_state = S_MASTER_ACK_ADDR;
                }
                else
                {
                    // Next state is transmit
                    i2c_state = S_MASTER_SEND_DATA;
                }
            }
            break;

        case S_MASTER_SEND_DATA:

            // Make sure the previous byte was acknowledged
            if(I2C_ACKNOWLEDGE_STATUS_BIT)
            {
                // Transmission was not acknowledged
                i2c_object.i2cErrors++;

                // Reset the Ack flag
                I2C_ACKNOWLEDGE_STATUS_BIT = 0;

                // Send a stop flag and go back to idle
                I2C_Stop(I2C_DATA_NO_ACK);

            }
            else
            {
                // Did we send them all ?
                if(i2c_bytes_left-- == 0U)
                {
                    // yup sent them all!

                    // update the trb pointer
                    p_i2c_trb_current++;

                    // are we done with this string of requests?
                    if(--i2c_trb_count == 0)
                    {
                        I2C_Stop(I2C_MESSAGE_COMPLETE);
                    }
                    else
                    {
                        // no!, there are more TRB to be sent.
                        //I2C_START_CONDITION_ENABLE_BIT = 1;

                        // In some cases, the slave may require
                        // a restart instead of a start. So use this one
                        // instead.
                        I2C_REPEAT_START_CONDITION_ENABLE_BIT = 1;

                        // start the i2c request
                        i2c_state = S_MASTER_SEND_ADDR;

                    }
                }
                else
                {
                    // Grab the next data to transmit
                    I2C_TRANSMIT_REG = *pi2c_buf_ptr++;
                }
            }
            break;

        case S_MASTER_ACK_ADDR:

            /* Make sure the previous byte was acknowledged */
            if(I2C_ACKNOWLEDGE_STATUS_BIT)
            {

                // Transmission was not acknowledged
                i2c_object.i2cErrors++;

                // Send a stop flag and go back to idle
                I2C_Stop(I2C_MESSAGE_ADDRESS_NO_ACK);

                // Reset the Ack flag
                I2C_ACKNOWLEDGE_STATUS_BIT = 0;
            }
            else
            {
                I2C_RECEIVE_ENABLE_BIT = 1;
                i2c_state = S_MASTER_ACK_RCV_DATA;
            }
            break;

        case S_MASTER_RCV_DATA:

            /* Acknowledge is completed.  Time for more data */

            // Next thing is to ack the data
            i2c_state = S_MASTER_ACK_RCV_DATA;

            // Set up to receive a byte of data
            I2C_RECEIVE_ENABLE_BIT = 1;

            break;

        case S_MASTER_ACK_RCV_DATA:

            // Grab the byte of data received and acknowledge it
            *pi2c_buf_ptr++ = I2C_RECEIVE_REG;

            // Check if we received them all?
            if(--i2c_bytes_left)
            {

                /* No, there's more to receive */

                // No, bit 7 is clear.  Data is ok
                // Set the flag to acknowledge the data
                I2C_ACKNOWLEDGE_DATA_BIT = 0;

                // Wait for the acknowledge to complete, then get more
                i2c_state = S_MASTER_RCV_DATA;
            }
            else
            {

                // Yes, it's the last byte.  Don't ack it
                // Flag that we will nak the data
                I2C_ACKNOWLEDGE_DATA_BIT = 1;

                I2C_FunctionComplete();
            }

            // Initiate the acknowledge
            I2C_ACKNOWLEDGE_ENABLE_BIT = 1;
            break;

        case S_MASTER_RCV_STOP:                
        case S_MASTER_SEND_STOP:

            // Send the stop flag
            I2C_Stop(I2C_MESSAGE_COMPLETE);
            break;

        default:

            // This case should not happen, if it does then
            // terminate the transfer
            i2c_object.i2cErrors++;
            I2C_Stop(I2C_LOST_STATE);
            break;

    }
}

void I2C_FunctionComplete(void)
{

    // update the trb pointer
    p_i2c_trb_current++;

    // are we done with this string of requests?
    if(--i2c_trb_count == 0)
    {
        i2c_state = S_MASTER_SEND_STOP;
    }
    else
    {
        i2c_state = S_MASTER_RESTART;
    }

}

void I2C_Stop(I2C_MESSAGE_STATUS completion_code)
{
    // then send a stop
    I2C_STOP_CONDITION_ENABLE_BIT = 1;

    // make sure the flag pointer is not NULL
    if (p_i2c_current->pTrFlag != NULL)
    {
        // update the flag with the completion code
        *(p_i2c_current->pTrFlag) = completion_code;
    }

    // Done, back to idle
    i2c_state = S_MASTER_IDLE;
    
}

void I2C_MasterWrite(
                                uint8_t *pdata,
                                uint8_t length,
                                uint16_t address,
                                I2C_MESSAGE_STATUS *pflag)
{
    static I2C_TRANSACTION_REQUEST_BLOCK   trBlock;

    // check if there is space in the queue
    if (i2c_object.trStatus.s.full != true)
    {
        I2C_MasterWriteTRBBuild(&trBlock, pdata, length, address);
        I2C_MasterTRBInsert(1, &trBlock, pflag);
    }
    else
    {
        *pflag = I2C_MESSAGE_FAIL;
    }

}

void I2C_MasterRead(
                                uint8_t *pdata,
                                uint8_t length,
                                uint16_t address,
                                I2C_MESSAGE_STATUS *pflag)
{
    static I2C_TRANSACTION_REQUEST_BLOCK   trBlock;


    // check if there is space in the queue
    if (i2c_object.trStatus.s.full != true)
    {
        I2C_MasterReadTRBBuild(&trBlock, pdata, length, address);
        I2C_MasterTRBInsert(1, &trBlock, pflag);
    }
    else
    {
        *pflag = I2C_MESSAGE_FAIL;
    }

}


inline void I2C_WaitForLastPacketToComplete()
{
    while(i2c_state != S_MASTER_IDLE)
    {
        // If your code gets stuck here it is because the last packet is never completing
        // Most likely cause is that your interrupt is not firing as it should. Check if you have
        //   correctly enabled all MSSP, Peripheral and GIE interrupt settings.
    }
}

void I2C_MasterTRBInsert(
                                uint8_t count,
                                I2C_TRANSACTION_REQUEST_BLOCK *ptrb_list,
                                I2C_MESSAGE_STATUS *pflag)
{

    // check if there is space in the queue
    if (i2c_object.trStatus.s.full != true)
    {
        *pflag = I2C_MESSAGE_PENDING;

        i2c_object.pTrTail->ptrb_list = ptrb_list;
        i2c_object.pTrTail->count     = count;
        i2c_object.pTrTail->pTrFlag   = pflag;
        i2c_object.pTrTail++;

        // check if the end of the array is reached
        if (i2c_object.pTrTail == (i2c_tr_queue + I2C_CONFIG_TR_QUEUE_LENGTH))
        {
            // adjust to restart at the beginning of the array
            i2c_object.pTrTail = i2c_tr_queue;
        }

        // since we added one item to be processed, we know
        // it is not empty, so set the empty status to false
        i2c_object.trStatus.s.empty = false;

        // check if full
        if (i2c_object.pTrHead == i2c_object.pTrTail)
        {
            // it is full, set the full status to true
            i2c_object.trStatus.s.full = true;
        }

    }
    else
    {
        *pflag = I2C_MESSAGE_FAIL;
    }

    // for interrupt based
    if (*pflag == I2C_MESSAGE_PENDING)
    {
        I2C_WaitForLastPacketToComplete();
        
        // The state machine has to be started manually because it runs only in the ISR.
        // If we called the ISR function here function duplication would double the code size
        //    because this function would be called both from interrupt and from mainline code.
        PIR1bits.SSP1IF = true;

    }   // block until request is complete

}

void I2C_MasterReadTRBBuild(
                                I2C_TRANSACTION_REQUEST_BLOCK *ptrb,
                                uint8_t *pdata,
                                uint8_t length,
                                uint16_t address)
{
    ptrb->address  = address << 1;
    // make this a read
    ptrb->address |= 0x01;
    ptrb->length   = length;
    ptrb->pbuffer  = pdata;
}

void I2C_MasterWriteTRBBuild(
                                I2C_TRANSACTION_REQUEST_BLOCK *ptrb,
                                uint8_t *pdata,
                                uint8_t length,
                                uint16_t address)
{
    ptrb->address = address << 1;
    ptrb->length  = length;
    ptrb->pbuffer = pdata;
}

bool I2C_MasterQueueIsEmpty(void)
{
    return(i2c_object.trStatus.s.empty);
}

bool I2C_MasterQueueIsFull(void)
{
    return(i2c_object.trStatus.s.full);
}        
        
void I2C_BusCollisionISR( void )
{
    // enter bus collision handling code here
	PIR2bits.BCL1IF = 0;
}        
        
        
/**
 End of File
*/
