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#include "msg_queues.h"

#include "maindefs.h"

//#include <i2c.h>

#include "i2c.h"

#pragma udata i2c_data

unsigned char i2c_buffer[MAXI2CBUF];

#pragma udata

I2C_DATA *i2c_pdata;

// Set up the data structures for the i2c code

// Should be called once before any i2c routines are called

void i2c_init(I2C_DATA *data) {

    i2c_pdata = data;

    i2c_pdata->buffer = i2c_buffer;

    i2c_pdata->buflen = 0;

    i2c_pdata->slave_event_count = 0;

    i2c_pdata->status = I2C_IDLE;

    i2c_pdata->slave_error_count = 0;

    i2c_pdata->bufind = 0;

    i2c_pdata->buflen = 0;

    i2c_pdata->slave_in_last_byte = 0;

    i2c_pdata->slave_sending_data = 0;

    i2c_pdata->slave_sending_blank_data = 0;

    i2c_pdata->mode = 0;

    i2c_pdata->master_dest_addr = 0;

    i2c_pdata->master_state = I2C_MASTER_IDLE;

}

// Setup the PIC to operate as a master.

void i2c_configure_master() {

    i2c_pdata->mode = I2C_MODE_MASTER;

    TRISCbits.TRISC3 = 1;

    TRISCbits.TRISC4 = 1;

    SSPSTAT = 0x0;

    SSPCON1 = 0x0;

    SSPCON2 = 0x0;

    SSPCON1bits.SSPM = 0x8; // I2C Master Mode

    /* SSPADD = (( Fosc/bit rate) / 4 ) - 1 */

#ifdef _REMOTE

    SSPADD = 0x63;          // Operate at 100KHz (40MHz)

#endif

#ifdef _BASE_STATION

    SSPADD = 0x4F;          // Operate at 100KHz (32MHz)

#endif

    SSPSTATbits.SMP = 1;    // Disable Slew Rate Control

    SSPCON1bits.SSPEN = 1;  // Enable MSSP Module

}

// Sends length number of bytes in msg to specified address (no R/W bit)

void i2c_master_send(unsigned char address, unsigned char length, unsigned char *msg) {

    int i;

    if (length == 0)

        return;

    // Copy message to send into buffer and save length/address

    for (i = 0; i < length; i++) {

        i2c_pdata->buffer[i] = msg[i];

    }

    i2c_pdata->buflen = length;

    i2c_pdata->master_dest_addr = address;

    i2c_pdata->bufind = 0;

    // Change status to 'next' operation

    i2c_pdata->status = I2C_SEND_ADDR;

    i2c_pdata->master_state = I2C_MASTER_SEND;

    // Generate start condition

    SSPCON2bits.SEN = 1;

}

// Reads length number of bytes from address (no R/W bit)

void i2c_master_recv(unsigned char address, unsigned char length) {

    if (length == 0)

        return;

    // Save length and address to get data from

    i2c_pdata->buflen = length;

    i2c_pdata->master_dest_addr = address;

    i2c_pdata->bufind = 0;

    // Change status to 'next' operation

    i2c_pdata->status = I2C_SEND_ADDR;

    i2c_pdata->master_state = I2C_MASTER_RECV;

    // Generate start condition

    SSPCON2bits.SEN = 1;

}

// Setup the PIC to operate as a slave. The address must not include the R/W bit

void i2c_configure_slave(unsigned char addr) {

    i2c_pdata->mode = I2C_MODE_SLAVE;

    // Ensure the two lines are set for input (we are a slave)

    TRISCbits.TRISC3 = 1;

    TRISCbits.TRISC4 = 1;

    SSPADD = addr << 1;     // Set the slave address

    SSPSTAT = 0x0;

    SSPCON1 = 0x0;

    SSPCON2 = 0x0;

    SSPCON1bits.SSPM = 0xE; // Enable Slave 7-bit w/ start/stop interrupts

    SSPSTATbits.SMP = 1;    // Slew Off

    SSPCON2bits.SEN = 1;    // Enable clock-stretching

    SSPCON1bits.SSPEN = 1;  // Enable MSSP Module

}

void i2c_interrupt_handler() {

    // Call interrupt depending on which mode we are operating in

    if (i2c_pdata->mode == I2C_MODE_MASTER) {

        i2c_interrupt_master();

    } else if (i2c_pdata->mode == I2C_MODE_SLAVE) {

        i2c_interrupt_slave();

    }

}

// An internal subroutine used in the master version of the i2c_interrupt_handler

void i2c_interrupt_master() {

    // If we are in the middle of sending data

    if (i2c_pdata->master_state == I2C_MASTER_SEND) {

        switch (i2c_pdata->status) {

            case I2C_IDLE:

                break;

            case I2C_SEND_ADDR:

                // Send the address with read bit set

                i2c_pdata->status = I2C_CHECK_ACK;

                SSPBUF = (i2c_pdata->master_dest_addr << 1) | 0x0;

                break;

            case I2C_CHECK_ACK:

                // Check if ACK is received or not

                if (!SSPCON2bits.ACKSTAT) {

                    // If an ACK is received, send next byte of data

                    if (i2c_pdata->bufind < i2c_pdata->buflen) {

                        SSPBUF = i2c_pdata->buffer[i2c_pdata->bufind];

                        i2c_pdata->bufind++;

                    } else {

                        // If no more data is to be sent, send stop bit

                        i2c_pdata->status = I2C_IDLE;

                        SSPCON2bits.PEN = 1;

                        i2c_pdata->master_state = I2C_MASTER_IDLE;

                        MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_SEND_COMPLETE, (void *) 0);

                    }

                } else {

                    // If a NACK is received, stop transmission and send error

                    i2c_pdata->status = I2C_IDLE;

                    SSPCON2bits.PEN = 1;

                    i2c_pdata->master_state = I2C_MASTER_IDLE;

                    MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_SEND_FAILED, (void *) 0);

                }

                break;

        }

    // If we are in the middle of receiving data

    } else if (i2c_pdata->master_state == I2C_MASTER_RECV) {

        switch (i2c_pdata->status) {

            case I2C_IDLE:

                break;

            case I2C_SEND_ADDR:

                // Send address with write bit set

                i2c_pdata->status = I2C_CHECK_ACK;

                SSPBUF = (i2c_pdata->master_dest_addr << 1) | 0x1;

                break;

            case I2C_CHECK_ACK:

                // Check if ACK is received

                if (!SSPCON2bits.ACKSTAT) {

                    // If an ACK is received, set module to receive 1 byte of data

                    i2c_pdata->status = I2C_RCV_DATA;

                    SSPCON2bits.RCEN = 1;

                } else {

                    // If a NACK is received, stop transmission and send error

                    i2c_pdata->status = I2C_IDLE;

                    SSPCON2bits.PEN = 1;

                    i2c_pdata->master_state = I2C_MASTER_IDLE;

                    MQ_sendmsg_ToMainFromHigh(0, MSGTYPE_I2C_MASTER_RECV_FAILED, (void *) 0);

                }

                break;

            case I2C_RCV_DATA:

                // On receive, save byte into buffer

                i2c_pdata->buffer[i2c_pdata->bufind] = SSPBUF;

                i2c_pdata->bufind++;

                if (i2c_pdata->bufind < i2c_pdata->buflen) {

                    // If we still need to read, send an ACK to the slave

                    i2c_pdata->status = I2C_REQ_DATA;

                    SSPCON2bits.ACKDT = 0;  // ACK

                    SSPCON2bits.ACKEN = 1;

                } else {

                    // If we are done reading, send an NACK to the slave

                    i2c_pdata->status = I2C_SEND_STOP;

                    SSPCON2bits.ACKDT = 1;  // NACK

                    SSPCON2bits.ACKEN = 1;

                }

                break;

            case I2C_REQ_DATA:

                // Set module to receive one byte of data

                i2c_pdata->status = I2C_RCV_DATA;

                SSPCON2bits.RCEN = 1;

                break;

            case I2C_SEND_STOP:

                // Send the stop bit and copy message to send to Main()

                i2c_pdata->status = I2C_IDLE;

                SSPCON2bits.PEN = 1;

                i2c_pdata->master_state = I2C_MASTER_IDLE;

                MQ_sendmsg_ToMainFromHigh(i2c_pdata->buflen, MSGTYPE_I2C_MASTER_RECV_COMPLETE, (void *) i2c_pdata->buffer);

                break;

        }

    }

}

// An internal subroutine used in the slave version of the i2c_interrupt_handler

void i2c_handle_start(unsigned char data_read) {

    i2c_pdata->slave_event_count = 1;

    i2c_pdata->buflen = 0;

    // Check to see if we also got the address

    if (data_read) {

        if (SSPSTATbits.D_A == 1) {

            DBG_PRINT_I2C("I2C Start: (ERROR) no address recieved\r\n");

            // This is bad because we got data and we wanted an address

            i2c_pdata->status = I2C_IDLE;

            i2c_pdata->slave_error_count++;

            i2c_pdata->slave_error_code = I2C_ERR_NOADDR;

        } else {

            if (SSPSTATbits.R_W == 1) {

                i2c_pdata->status = I2C_SEND_DATA;

            } else {

                i2c_pdata->status = I2C_RCV_DATA;

            }

        }

    } else {

        i2c_pdata->status = I2C_STARTED;

    }

}

void i2c_interrupt_slave() {

    unsigned char i2c_data;

    unsigned char data_read_from_buffer = 0;

    unsigned char data_written_to_buffer = 0;

    unsigned char msg_send_data_to_main = 0;

    unsigned char overrun_error = 0;

    unsigned char error_buf[3];

    unsigned char msgtype = 0;

    // Clear SSPOV (overflow bit)

    if (SSPCON1bits.SSPOV == 1) {

        DBG_PRINT_I2C("I2C: overflow detected\r\n");

        SSPCON1bits.SSPOV = 0;

        // We failed to read the buffer in time, so we know we

        //  can't properly receive this message, just put us in the

        //  a state where we are looking for a new message

        i2c_pdata->status = I2C_IDLE;

        overrun_error = 1;

        i2c_pdata->slave_error_count++;

        i2c_pdata->slave_error_code = I2C_ERR_OVERRUN;

    }

    // Read SPPxBUF if it is full

    if (SSPSTATbits.BF == 1) {

        i2c_data = SSPBUF;

        DBG_PRINT_I2C("I2C: data read from buffer: %x\r\n", SSPBUF);

        data_read_from_buffer = 1;

    }

    if (!overrun_error) {

        switch (i2c_pdata->status) {

            case I2C_IDLE:

            {

                // Ignore anything except a start

                if (SSPSTATbits.S == 1) {

                    i2c_handle_start(data_read_from_buffer);

                    // If we see a slave read, then we need to handle it here

                    if (i2c_pdata->status == I2C_SEND_DATA) {

                        // Return the first byte (message id)

                        SSPBUF = 0x3;

                    }

                }

                break;

            }

            case I2C_STARTED:

            {

                // In this case, we expect either an address or a stop bit

                if (SSPSTATbits.P == 1) {

                    // We need to check to see if we also read an address (a message of length 0)

                    i2c_pdata->slave_event_count++;

                    if (data_read_from_buffer) {

                        if (SSPSTATbits.D_A == 0) {

                            msg_send_data_to_main = 1;

                        } else {

                            DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");

                            i2c_pdata->slave_error_count++;

                            i2c_pdata->slave_error_code = I2C_ERR_NODATA;

                        }

                    }

                    // Return to idle mode

                    i2c_pdata->status = I2C_IDLE;

                } else if (data_read_from_buffer) {

                    i2c_pdata->slave_event_count++;

                    if (SSPSTATbits.D_A == 0) {

                        if (SSPSTATbits.R_W == 0) {  // Slave write

                            i2c_pdata->status = I2C_RCV_DATA;

                        } else {    // Slave read

                            i2c_pdata->status = I2C_SEND_DATA;

                            // Return the first byte (message id)

                            SSPBUF = 0x3;

                        }

                    } else {

                        DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");

                        i2c_pdata->slave_error_count++;

                        i2c_pdata->status = I2C_IDLE;

                        i2c_pdata->slave_error_code = I2C_ERR_NODATA;

                    }

                }

                break;

            }

            case I2C_SEND_DATA:

            {

                // If we arnt current in the middle of sending data, check to see

                //  if there is a message in the queue to send

                if (!i2c_pdata->slave_sending_data) {

                    // Check the message type of the next message in queue

                    msgtype = MQ_peek_FromMainToHigh();

                    if (msgtype != MSGTYPE_I2C_REPLY || msgtype == 0) {

                        // If the message queue is empty or to another interrupt processor, return 0xFF

                        DBG_PRINT_I2C("I2C: Returning 0xFF [%d:%d]\r\n", 0, i2c_pdata->slave_in_last_byte-1);

                        SSPBUF = 0xFF;

                        i2c_pdata->bufind = 1;

                        i2c_pdata->slave_sending_data = 1;

                        i2c_pdata->slave_sending_blank_data = 1;

                        data_written_to_buffer = 1;

                    } else {

                        i2c_pdata->buflen = MQ_recvmsg_FromMainToHigh(MSGLEN, (unsigned char *)i2c_pdata->slave_outbufmsgtype, (void *) i2c_pdata->buffer);

//                        DBG_PRINT_I2C("%x\r\n",i2c_ptr->buffer[0]);

//                        DBG_PRINT_I2C("I2C: buffer Message Length: %d\r\n",i2c_ptr->outbuflen);

                        if (i2c_pdata->buflen > 0) {

                            // Otherwise return the first byte of data

                            DBG_PRINT_I2C("I2C: Returning %x [%d,%d]\r\n", i2c_pdata->buffer[0], 0, i2c_pdata->buflen-1);

                            SSPBUF = i2c_pdata->buffer[0];

                            i2c_pdata->bufind = 1;

                            i2c_pdata->slave_sending_data = 1;

                            data_written_to_buffer = 1;

                        } else {

                            DBG_PRINT_I2C("I2C: (ERROR) Unexpected msg in queue, type = %x\r\n", i2c_pdata->slave_outbufmsgtype);

                        }

                    }

                } else if (i2c_pdata->slave_sending_blank_data) {

                    // If we are currently sending 0xFFs back, keep sending for the requested number of bytes

                    if (i2c_pdata->bufind < i2c_pdata->slave_in_last_byte) {

                        DBG_PRINT_I2C("I2C: Returning 0xFF [%d:%d]\r\n", i2c_pdata->bufind, i2c_pdata->slave_in_last_byte-1);

                        SSPBUF = 0xFF;

                        i2c_pdata->bufind++;

                        data_written_to_buffer = 1;

                    } else {

                        // We have nothing left to send

                        i2c_pdata->slave_sending_data = 0;

                        i2c_pdata->slave_sending_blank_data = 0;

                        i2c_pdata->status = I2C_IDLE;

                    }

                } else {

                    // Otherwise keep sending back the requested data

                    if (i2c_pdata->bufind < i2c_pdata->buflen) {

                        DBG_PRINT_I2C("I2C: Returning %x [%d,%d]\r\n", i2c_pdata->buffer[i2c_pdata->bufind], i2c_pdata->bufind, i2c_pdata->buflen-1);

                        SSPBUF = i2c_pdata->buffer[i2c_pdata->bufind];

                        i2c_pdata->bufind++;

                        data_written_to_buffer = 1;

                    } else {

                        // We have nothing left to send

                        i2c_pdata->slave_sending_data = 0;

                        i2c_pdata->status = I2C_IDLE;

                    }

                }

                break;

            }

            case I2C_RCV_DATA:

            {

                // We expect either data or a stop bit or a (if a restart, an addr)

                if (SSPSTATbits.P == 1) {

                    // We need to check to see if we also read data

                    i2c_pdata->slave_event_count++;

                    if (data_read_from_buffer) {

                        if (SSPSTATbits.D_A == 1) {

                            i2c_pdata->buffer[i2c_pdata->buflen] = i2c_data;

                            i2c_pdata->buflen++;

                            msg_send_data_to_main = 1;

                        } else {

                            DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");

                            i2c_pdata->slave_error_count++;

                            i2c_pdata->slave_error_code = I2C_ERR_NODATA;

                            i2c_pdata->status = I2C_IDLE;

                        }

                    } else {

                        msg_send_data_to_main = 1;

                    }

                    i2c_pdata->status = I2C_IDLE;

                } else if (data_read_from_buffer) {

                    i2c_pdata->slave_event_count++;

                    if (SSPSTATbits.D_A == 1) {

                        i2c_pdata->buffer[i2c_pdata->buflen] = i2c_data;

                        i2c_pdata->buflen++;

                    } else /* a restart */ {

                        if (SSPSTATbits.R_W == 1) {

                            i2c_pdata->status = I2C_SEND_DATA;

                            msg_send_data_to_main = 1;

                            // Return the first byte (message id)

                            SSPBUF = 0x3;

                        } else { // Bad to recv an address again, we aren't ready

                            DBG_PRINT_I2C("I2C: (ERROR) no data recieved\r\n");

                            i2c_pdata->slave_error_count++;

                            i2c_pdata->slave_error_code = I2C_ERR_NODATA;

                            i2c_pdata->status = I2C_IDLE;

                        }

                    }

                }

                break;

            }

        }

    }

    // Release the clock stretching bit (if we should)

    if (data_read_from_buffer || data_written_to_buffer) {

        // Release the clock

        if (SSPCON1bits.CKP == 0) {

            SSPCON1bits.CKP = 1;

        }

    }

    // Must check if the message is too long

    if ((i2c_pdata->buflen > MAXI2CBUF - 2) && (!msg_send_data_to_main)) {

        DBG_PRINT_I2C("I2C: (ERROR) message too long\r\n");

        i2c_pdata->status = I2C_IDLE;

        i2c_pdata->slave_error_count++;

        i2c_pdata->slave_error_code = I2C_ERR_MSGTOOLONG;

    }

    if (msg_send_data_to_main) {

        DBG_PRINT_I2C("I2C: sending message to main()\r\n");

        i2c_pdata->slave_in_last_byte = i2c_pdata->buffer[i2c_pdata->buflen-1];

        i2c_pdata->buffer[i2c_pdata->buflen] = i2c_pdata->slave_event_count;

        MQ_sendmsg_ToMainFromHigh(i2c_pdata->buflen + 1, MSGTYPE_I2C_DATA, (void *) i2c_pdata->buffer);

        i2c_pdata->buflen = 0;

    } else if (i2c_pdata->slave_error_count >= I2C_ERR_THRESHOLD) {

        DBG_PRINT_I2C("I2C: (ERROR) error threshold passed\r\n");

        error_buf[0] = i2c_pdata->slave_error_count;

        error_buf[1] = i2c_pdata->slave_error_code;

        error_buf[2] = i2c_pdata->slave_event_count;

        MQ_sendmsg_ToMainFromHigh(sizeof (unsigned char) *3, MSGTYPE_I2C_DBG, (void *) error_buf);

        i2c_pdata->slave_error_count = 0;

    }

}

unsigned char i2c_master_busy() {

    if (i2c_pdata->master_state == I2C_MASTER_IDLE) {

        return 0;

    } else {

        return 1;

    }

}