//*****************************************************************************
//
// i2c_slave.c - I2C slave interface for the main microcontroller.
//
// Copyright (c) 2006-2007 Luminary Micro, Inc.  All rights reserved.
//
// Software License Agreement
//
// Luminary Micro, Inc. (LMI) is supplying this software for use solely and
// exclusively on LMI's microcontroller products.
//
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws.  All rights are reserved.  Any use in violation
// of the foregoing restrictions may subject the user to criminal sanctions
// under applicable laws, as well as to civil liability for the breach of the
// terms and conditions of this license.
//
// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 220 of sw01246.
//
//*****************************************************************************

#include "hw_i2c.h"
#include "hw_ints.h"
#include "hw_memmap.h"
#include "hw_types.h"
#include "gpio.h"
#include "i2c.h"
#include "interrupt.h"
#include "i2ccmds.h"
#include "draw.h"
#include "main.h"
#include "switches.h"
#include "table.h"

//*****************************************************************************
//
//! \page main_i2c_slave_intro Introduction
//!
//! The main microcontroller receives commands from the user interface
//! microcontroller via an I2C link.  The I2C interface on the main
//! microcontroller is run in slave mode; I2C writes provide configuration and
//! commands, and I2C reads return status of the CNC machine.
//!
//! The I2C interface is operated in interrupt driven mode so that it incurs a
//! minimal overhead to the remainder of the application.  Since the I2C
//! interface operates one byte per interrupt, special handling is required for
//! multi-byte commands and status.  The first interrupt will determine what
//! operation is being performed (status read, sending the name string, etc.).
//! Flags are set that help determine how subsequent interrupts (and therefore
//! bytes) are handled.
//!
//! The code for the I2C slave interface is contained in
//! <tt>main_micro/i2c_slave.c</tt>, with <tt>main_micro/i2c_slave.h</tt>
//! containing the API definitions for use by the remainder of the
//! application.
//
//*****************************************************************************

//*****************************************************************************
//
//! \defgroup main_i2c_slave_api Definitions
//! @{
//
//*****************************************************************************

//*****************************************************************************
//
//! The GPIO pin on port B that is used for the I2C clock signal.
//
//*****************************************************************************
#define PIN_SCL                 GPIO_PIN_2

//*****************************************************************************
//
//! The GPIO pin on port B that is used for the I2C data signal.
//
//*****************************************************************************
#define PIN_SDA                 GPIO_PIN_3

//*****************************************************************************
//
//! The speed used for diagnostic moves along the X axis, specified in steps
//! per second.
//
//*****************************************************************************
#define X_SPEED                 2400

//*****************************************************************************
//
//! The acceleration used for diagnostic moves along the X axis, specified in
//! steps per second^2.
//
//*****************************************************************************
#define X_ACCEL                 30000

//*****************************************************************************
//
//! The speed used for diagnostic moves along the Y axis, specified in steps
//! per second.
//
//*****************************************************************************
#define Y_SPEED                 2400

//*****************************************************************************
//
//! The acceleration used for diagnostic moves along the Y axis, specified in
//! steps per second^2.
//
//*****************************************************************************
#define Y_ACCEL                 30000

//*****************************************************************************
//
//! The speed used for diagnostic moves along the Z axis, specified in steps
//! per second.
//
//*****************************************************************************
#define Z_SPEED                 1200

//*****************************************************************************
//
//! The acceleration used for diagnostic moves along the Z axis, specified in
//! steps per second^2.
//
//*****************************************************************************
#define Z_ACCEL                 30000

//*****************************************************************************
//
//! A set of flags for controlling the I2C slave interface; contains the
//! #I2CS_FLAG_START, #I2CS_FLAG_STOP, #I2CS_FLAG_NAME, #I2CS_FLAG_ICONS, and
//! #I2CS_FLAG_TOOL flags.
//
//*****************************************************************************
static unsigned long g_ulI2CFlags;

//*****************************************************************************
//
//! The bit number in #g_ulI2CFlags of the flag that is set when an I2C start
//! condition is detected.
//
//*****************************************************************************
#define I2CS_FLAG_START         0

//*****************************************************************************
//
//! The bit number in #g_ulI2CFlags of the flag that is set when an I2C stop
//! condition is detected.
//
//*****************************************************************************
#define I2CS_FLAG_STOP          1

//*****************************************************************************
//
//! The bit number in #g_ulI2CFlags of the flag that is set when the name
//! string is being transferred via the I2C interface.
//
//*****************************************************************************
#define I2CS_FLAG_NAME          2

//*****************************************************************************
//
//! The bit number in #g_ulI2CFlags of the flag that is set when the icon set
//! is being transferred via the I2C interface.
//
//*****************************************************************************
#define I2CS_FLAG_ICONS         3

//*****************************************************************************
//
//! The bit number in #g_ulI2CFlags of the flag that is set when the tool
//! selection is being transferred via the I2C interface.
//
//*****************************************************************************
#define I2CS_FLAG_TOOL          4

//*****************************************************************************
//
//! This array contains the status being written in response to a I2C read
//! request.
//
//*****************************************************************************
static unsigned char g_pucI2CStatus[16];

//*****************************************************************************
//
//! The current index into the name string (for name writes) or the status
//! buffer (for status reads); used to sequence through the corresponding
//! buffers one byte at a time for each I2C data request.
//
//*****************************************************************************
static unsigned long g_ulI2CIndex;

//*****************************************************************************
//
//! Looks for I2C start and stop conditions.
//!
//! This interrupt handler is called in response to edges on the I2C data line.
//! If the data line changes while the I2C clock line is high, then a start or
//! stop condition has occurred.
//!
//! \return None.
//
//*****************************************************************************
void
GPIOBIntHandler(void)
{
    unsigned long ulPins;

    //
    // Clear the GPIO pin interrupt.
    //
    GPIOPinIntClear(GPIO_PORTB_BASE, PIN_SDA);

    //
    // Read the current state of the I2C clock and data lines.
    //
    ulPins = GPIOPinRead(GPIO_PORTB_BASE, PIN_SCL | PIN_SDA);

    //
    // If the clock line is high and the data line is low, then a start
    // condition has just occurred.
    //
    if(ulPins == PIN_SCL)
    {
        //
        // Indicate that a start has just occurred.
        //
        HWREGBITW(&g_ulI2CFlags, I2CS_FLAG_START) = 1;
    }

    //
    // If the clock line is high and the data line is high, then a stop
    // condition has just occurred.
    //
    else if(ulPins == (PIN_SCL | PIN_SDA))
    {
        //
        // Indicate that a stop has just occurred.
        //
        HWREGBITW(&g_ulI2CFlags, I2CS_FLAG_STOP) = 1;
    }
}

//*****************************************************************************
//
//! Handle a command sent from the I2C master.
//!
//! This function processes a command sent from the I2C master.  Most commands
//! are handled completely from the single command byte, while the name string,
//! icon set, and tool selection commands require additional I2C transfers.
//!
//! \return None.
//
//*****************************************************************************
static void
I2CHandleCommand(void)
{
    long lXPos, lYPos, lZPos;

    //
    // Read the command byte from the I2C slave and determine how to handle it.
    //
    switch(I2CSlaveDataGet(I2C_SLAVE_BASE))
    {
        //
        // A positive move along the X axis is being requested.
        //
        case CMD_X_PLUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the positive direction along the X axis.
                //
                TableMoveLine(lXPos + 0x40000000, lYPos, lZPos, X_SPEED,
                              X_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // A negative move along the X axis is being requested.
        //
        case CMD_X_MINUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the negative direction along the X axis.
                //
                TableMoveLine(lXPos - 0x40000000, lYPos, lZPos, X_SPEED,
                              X_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // A positive move along the Y axis is being requested.
        //
        case CMD_Y_PLUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the positive direction along the Y axis.
                //
                TableMoveLine(lXPos, lYPos + 0x40000000, lZPos, Y_SPEED,
                              Y_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // A negative move along the Y axis is being requested.
        //
        case CMD_Y_MINUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the negative direction along the Y axis.
                //
                TableMoveLine(lXPos, lYPos - 0x40000000, lZPos, Y_SPEED,
                              Y_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // A positive move along the Z axis is being requested.
        //
        case CMD_Z_PLUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the positive direction along the Z axis.
                //
                TableMoveLine(lXPos, lYPos, lZPos + 0x40000000, Z_SPEED,
                              Z_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // A negative move along the Z axis is being requested.
        //
        case CMD_Z_MINUS:
        {
            //
            // See if the table is presently moving.
            //
            if(!TableIsMoving() && !DrawIsDrawing())
            {
                //
                // The table is not moving, so get the current table position.
                //
                TableGetPosition(&lXPos, &lYPos, &lZPos);

                //
                // Move in the negative direction along the Z axis.
                //
                TableMoveLine(lXPos, lYPos, lZPos - 0x40000000, Z_SPEED,
                              Z_ACCEL);
            }

            //
            // Done with this command.
            //
            break;
        }

        //
        // Demo mode one is being selected.
        //
        case CMD_DEMO1:
        {
            //
            // Set the demo mode to one.
            //
            g_ulDemoMode = 1;

            //
            // Done with this command.
            //
            break;
        }