//###########################################################################
//
// FILE:	Example_2833xI2C_eeprom.c
//
// TITLE:	I2C EEPROM Example
//
//! \addtogroup f2833x_example_list
//! <h1>I2C EEPROM (i2c_eeprom)</h1>
//!
//!  This program requires an external I2C EEPROM connected to
//!  the I2C bus at address 0x50. \n
//!  This program will write 1-14 words to EEPROM and read them back.
//!  The data written and the EEPROM address written to are contained
//!  in the message structure, \b I2cMsgOut1. The data read back will be
//!  contained in the message structure \b I2cMsgIn1.
//!
//!  \b Watch \b Variables \n
//!  - I2cMsgIn1
//!  - I2cMsgOut1
//
//###########################################################################
// $TI Release: $
// $Release Date: $
// $Copyright:
// Copyright (C) 2009-2023 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
//   Redistributions of source code must retain the above copyright 
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the 
//   documentation and/or other materials provided with the   
//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

//
// Note: I2C Macros used in this example can be found in the
// DSP2833x_I2C_defines.h file
//

//
// Function Prototypes
//
void   I2CA_Init(void);
Uint16 I2CA_WriteData(struct I2CMSG *msg);
Uint16 I2CA_ReadData(struct I2CMSG *msg);
__interrupt void i2c_int1a_isr(void);
void pass(void);
void fail(void);

//
// Defines
//
#define I2C_SLAVE_ADDR        0x50
#define I2C_NUMBYTES          4
#define I2C_EEPROM_HIGH_ADDR  0x00
#define I2C_EEPROM_LOW_ADDR   0x30

//
// Globals
//

//
// Two bytes will be used for the outgoing address, thus only setup 14 bytes 
// maximum
//
struct I2CMSG I2cMsgOut1=
{
    I2C_MSGSTAT_SEND_WITHSTOP,
    I2C_SLAVE_ADDR,
    I2C_NUMBYTES,
    I2C_EEPROM_HIGH_ADDR,
    I2C_EEPROM_LOW_ADDR,
    0x12,                   // Msg Byte 1
    0x34,                   // Msg Byte 2
    0x56,                   // Msg Byte 3
    0x78,                   // Msg Byte 4
    0x9A,                   // Msg Byte 5
    0xBC,                   // Msg Byte 6
    0xDE,                   // Msg Byte 7
    0xF0,                   // Msg Byte 8
    0x11,                   // Msg Byte 9
    0x10,                   // Msg Byte 10
    0x11,                   // Msg Byte 11
    0x12,                   // Msg Byte 12
    0x13,                   // Msg Byte 13
    0x12                    // Msg Byte 14
};

struct I2CMSG I2cMsgIn1=
{   I2C_MSGSTAT_SEND_NOSTOP,
    I2C_SLAVE_ADDR,
    I2C_NUMBYTES,
    I2C_EEPROM_HIGH_ADDR,
    I2C_EEPROM_LOW_ADDR
};

//
// Globals
//
struct I2CMSG *CurrentMsgPtr;				// Used in interrupts
Uint16 PassCount;
Uint16 FailCount;

//
// Main
//
void main(void)
{
    Uint16 Error;
    Uint16 i;

    CurrentMsgPtr = &I2cMsgOut1;

    //
    // Step 1. Initialize System Control:
    // PLL, WatchDog, enable Peripheral Clocks
    // This example function is found in the DSP2833x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the DSP2833x_Gpio.c file and
    // illustrates how to set the GPIO to it's default state.
    //
    // InitGpio();
    
    //
    // Setup only the GP I/O only for I2C functionality
    //
    InitI2CGpio();

    //
    // Step 3. Clear all interrupts and initialize PIE vector table
    // Disable CPU interrupts
    //
    DINT;

    //
    // Initialize PIE control registers to their default state.
    // The default state is all PIE interrupts disabled and flags
    // are cleared.
    // This function is found in the DSP2833x_PieCtrl.c file.
    //
    InitPieCtrl();

    //
    // Disable CPU interrupts and clear all CPU interrupt flags
    //
    IER = 0x0000;
    IFR = 0x0000;

    //
    // Initialize the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    // This will populate the entire table, even if the interrupt
    // is not used in this example.  This is useful for debug purposes.
    // The shell ISR routines are found in DSP2833x_DefaultIsr.c.
    // This function is found in DSP2833x_PieVect.c.
    //
    InitPieVectTable();

    //
    // Interrupts that are used in this example are re-mapped to
    // ISR functions found within this file.
    //
    EALLOW;	    // This is needed to write to EALLOW protected registers
    PieVectTable.I2CINT1A = &i2c_int1a_isr;
    EDIS;   // This is needed to disable write to EALLOW protected registers

    //
    // Step 4. Initialize all the Device Peripherals:
    // This function is found in DSP2833x_InitPeripherals.c
    //
    // InitPeripherals(); // Not required for this example
    I2CA_Init();

    //
    // Step 5. User specific code
    //

    //
    // Clear Counters
    //
    PassCount = 0;
    FailCount = 0;

    //
    // Clear incoming message buffer
    //
    for (i = 0; i < I2C_MAX_BUFFER_SIZE; i++)
    {
        I2cMsgIn1.MsgBuffer[i] = 0x0000;
    }

    //
    // Enable interrupts required for this example
    //

    //
    // Enable I2C interrupt 1 in the PIE: Group 8 interrupt 1
    //
    PieCtrlRegs.PIEIER8.bit.INTx1 = 1;

    //
    // Enable CPU INT8 which is connected to PIE group 8
    //
    IER |= M_INT8;
    EINT;

    //
    // Application loop
    //
    for(;;)
    {
        //
        // Write data to EEPROM section
        //

        //
        // Check the outgoing message to see if it should be sent.
        // In this example it is initialized to send with a stop bit.
        //
        if(I2cMsgOut1.MsgStatus == I2C_MSGSTAT_SEND_WITHSTOP)
        {
            Error = I2CA_WriteData(&I2cMsgOut1);
            
            //
            // If communication is correctly initiated, set msg status to busy
            // and update CurrentMsgPtr for the interrupt service routine.
            // Otherwise, do nothing and try again next loop. Once message is
            // initiated, the I2C interrupts will handle the rest. Search for
            // ICINTR1A_ISR in the i2c_eeprom_isr.c file.
            //
            if (Error == I2C_SUCCESS)
            {
                CurrentMsgPtr = &I2cMsgOut1;
                I2cMsgOut1.MsgStatus = I2C_MSGSTAT_WRITE_BUSY;
            }
        }  // end of write section

        //
        // Read data from EEPROM section
        //

        //
        // Check outgoing message status. Bypass read section if status is
        // not inactive.
        //
        if (I2cMsgOut1.MsgStatus == I2C_MSGSTAT_INACTIVE)
        {
            //
            // Check incoming message status.
            //
            if(I2cMsgIn1.MsgStatus == I2C_MSGSTAT_SEND_NOSTOP)
            {
                //
                // EEPROM address setup portion
                //
                while(I2CA_ReadData(&I2cMsgIn1) != I2C_SUCCESS)
                {
                    //
                    // Maybe setup an attempt counter to break an infinite 
                    // while loop. The EEPROM will send back a NACK while it is 
                    // performing a write operation. Even though the write 
                    // communique is complete at this point, the EEPROM could 
                    // still be busy programming the data. Therefore, multiple 
                    // attempts are necessary.
                    //
                }
                
                //
                // Update current message pointer and message status
                //
                CurrentMsgPtr = &I2cMsgIn1;
                I2cMsgIn1.MsgStatus = I2C_MSGSTAT_SEND_NOSTOP_BUSY;
            }

            //
            // Once message has progressed past setting up the internal address
            // of the EEPROM, send a restart to read the data bytes from the
            // EEPROM. Complete the communique with a stop bit. MsgStatus is
            // updated in the interrupt service routine.
            //
            else if(I2cMsgIn1.MsgStatus == I2C_MSGSTAT_RESTART)
            {
                //
                // Read data portion
                //
                while(I2CA_ReadData(&I2cMsgIn1) != I2C_SUCCESS)
                {
                    //
                    // Maybe setup an attempt counter to break an infinite 
                    // while loop.
                    //
                }
                
                //
                // Update current message pointer and message status
                //
                CurrentMsgPtr = &I2cMsgIn1;
                I2cMsgIn1.MsgStatus = I2C_MSGSTAT_READ_BUSY;
            }
        }  // end of read section
    }   // end of for(;;)
}   // end of main

//
// I2CA_Init -
//
void 
I2CA_Init(void)
{
    //
    // Initialize I2C
    //
    I2caRegs.I2CSAR = 0x0050;	// Slave address - EEPROM control code

#if (CPU_FRQ_150MHZ)            // Default - For 150MHz SYSCLKOUT
    //
    // Prescaler - need 7-12 Mhz on module clk (150/15 = 10MHz)
    //
    I2caRegs.I2CPSC.all = 14;
#endif
#if (CPU_FRQ_100MHZ)            // For 100 MHz SYSCLKOUT
    //
    // Prescaler - need 7-12 Mhz on module clk (100/10 = 10MHz)
    //    
    I2caRegs.I2CPSC.all = 9;
#endif

    I2caRegs.I2CCLKL = 10;		// NOTE: must be non zero
    I2caRegs.I2CCLKH = 5;		// NOTE: must be non zero
    I2caRegs.I2CIER.all = 0x24;	// Enable SCD & ARDY interrupts

    //
    // Take I2C out of reset
    // Stop I2C when suspended
    //
    I2caRegs.I2CMDR.all = 0x0020;	

    I2caRegs.I2CFFTX.all = 0x6000;	// Enable FIFO mode and TXFIFO
    I2caRegs.I2CFFRX.all = 0x2040;	// Enable RXFIFO, clear RXFFINT,

    return;
}

//
// I2CA_WriteData -
//
Uint16 
I2CA_WriteData(struct I2CMSG *msg)
{
    Uint16 i;

    //
    // Wait until the STP bit is cleared from any previous master communication
    // Clearing of this bit by the module is delayed until after the SCD bit is
    // set. If this bit is not checked prior to initiating a new message, the
    // I2C could get confused.
    //
    if (I2caRegs.I2CMDR.bit.STP == 1)
    {
        return I2C_STP_NOT_READY_ERROR;
    }

    //
    // Setup slave address
    //
    I2caRegs.I2CSAR = msg->SlaveAddress;

    //
    // Check if bus busy
    //
    if (I2caRegs.I2CSTR.bit.BB == 1)
    {
        return I2C_BUS_BUSY_ERROR;
    }

    //
    // Setup number of bytes to send MsgBuffer + Address
    //
    I2caRegs.I2CCNT = msg->NumOfBytes+2;

    //
    // Setup data to send
    //
    I2caRegs.I2CDXR = msg->MemoryHighAddr;
    I2caRegs.I2CDXR = msg->MemoryLowAddr;

    for (i=0; i<msg->NumOfBytes; i++)
    {
        I2caRegs.I2CDXR = *(msg->MsgBuffer+i);
    }

    //
    // Send start as master transmitter
    //
    I2caRegs.I2CMDR.all = 0x6E20;

    return I2C_SUCCESS;
}

//
// I2CA_ReadData - 
//
Uint16 
I2CA_ReadData(struct I2CMSG *msg)
{
    //
    // Wait until the STP bit is cleared from any previous master communication.
    // Clearing of this bit by the module is delayed until after the SCD bit is
    // set. If this bit is not checked prior to initiating a new message, the
    // I2C could get confused.
    //
    if (I2caRegs.I2CMDR.bit.STP == 1)
    {
        return I2C_STP_NOT_READY_ERROR;
    }

    I2caRegs.I2CSAR = msg->SlaveAddress;

    if(msg->MsgStatus == I2C_MSGSTAT_SEND_NOSTOP)
    {
        //
        // Check if bus busy
        //
        if (I2caRegs.I2CSTR.bit.BB == 1)
        {
            return I2C_BUS_BUSY_ERROR;
        }
        I2caRegs.I2CCNT = 2;
        I2caRegs.I2CDXR = msg->MemoryHighAddr;
        I2caRegs.I2CDXR = msg->MemoryLowAddr;
        I2caRegs.I2CMDR.all = 0x2620;	// Send data to setup EEPROM address
    }
    else if(msg->MsgStatus == I2C_MSGSTAT_RESTART)
    {
        I2caRegs.I2CCNT = msg->NumOfBytes;	// Setup how many bytes to expect
        I2caRegs.I2CMDR.all = 0x2C20;		// Send restart as master receiver
    }

    return I2C_SUCCESS;
}

//
// i2c_int1a_isr - I2C-A
//
__interrupt void
i2c_int1a_isr(void)
{
    Uint16 IntSource, i;

    //
    // Read interrupt source
    //
    IntSource = I2caRegs.I2CISRC.all;

    //
    // Interrupt source = stop condition detected
    //
    if(IntSource == I2C_SCD_ISRC)
    {
        //
        // If completed message was writing data, reset msg to inactive state
        //
        if (CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_WRITE_BUSY)
        {
            CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_INACTIVE;
        }
        else
        {
            //
            // If a message receives a NACK during the address setup portion 
            // of the EEPROM read, the code further below included in the 
            // register access ready interrupt source code will generate a stop
            // condition. After the stop condition is received (here), set the 
            // message status to try again. User may want to limit the number 
            // of retries before generating an error.
            //
            if(CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_SEND_NOSTOP_BUSY)
            {
                CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_SEND_NOSTOP;
            }
            
            //
            // If completed message was reading EEPROM data, reset msg 
            // to inactive state and read data from FIFO.
            //
            else if (CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_READ_BUSY)
            {
                CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_INACTIVE;
                for(i=0; i < I2C_NUMBYTES; i++)
                {
                    CurrentMsgPtr->MsgBuffer[i] = I2caRegs.I2CDRR;
                }
                {
                    //
                    // Check received data
                    //
                    for(i=0; i < I2C_NUMBYTES; i++)
                    {
                        if(I2cMsgIn1.MsgBuffer[i] == I2cMsgOut1.MsgBuffer[i])
                        {
                            PassCount++;
                        }
                        else
                        {
                            FailCount++;
                        }
                    }
                    
                    if(PassCount == I2C_NUMBYTES)
                    {
                        pass();
                    }
                    else
                    {
                        fail();
                    }
                }
            }
        }
    }  // end of stop condition detected

    //
    // Interrupt source = Register Access Ready
    // This interrupt is used to determine when the EEPROM address setup 
    // portion of the read data communication is complete. Since no stop bit is
    // commanded, this flag tells us when the message has been sent instead of 
    // the SCD flag. If a NACK is received, clear the NACK bit and command a 
    // stop. Otherwise, move on to the read data portion of the communication.
    //
    else if(IntSource == I2C_ARDY_ISRC)
    {
        if(I2caRegs.I2CSTR.bit.NACK == 1)
        {
            I2caRegs.I2CMDR.bit.STP = 1;
            I2caRegs.I2CSTR.all = I2C_CLR_NACK_BIT;
        }
        else if(CurrentMsgPtr->MsgStatus == I2C_MSGSTAT_SEND_NOSTOP_BUSY)
        {
            CurrentMsgPtr->MsgStatus = I2C_MSGSTAT_RESTART;
        }
    }

    else
    {
        //
        // Generate some error due to invalid interrupt source
        //
        __asm("   ESTOP0");
    }

    //
    // Enable future I2C (PIE Group 8) interrupts
    //
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP8;
}

//
// pass - 
//
void pass()
{
    __asm("   ESTOP0");
    for(;;);
}

//
// fail -
//
void fail()
{
    __asm("   ESTOP0");
    for(;;);
}

//
// End of File
//