/*******************************************************************************************************
 *                                                                                                     *
 *        **********                                                                                   *
 *       ************                                                                                  *
 *      ***        ***                                                                                 *
 *      ***   +++   ***                                                                                *
 *      ***   + +   ***     This file implements LCD display initialization                            *
 *      ***   +             and functions for updating the LCD display                                 *
 *      ***   + +   ***                                                                                *
 *      ***   +++   ***     Lcd.c                                                                      *
 *      ***        ***                                                                                 *
 *       ************                                                                                  *
 *        **********                                                                                   *
 *                                                                                                     *
 *******************************************************************************************************
 * Compiler:                Keil C51 V7.50                                                             *
 * Target platform:         Chipcon, CCxx00                                                            *
 * Author:                  SNA                                                                        *
 *******************************************************************************************************
 * Revision history:        See end of file                                                            *
 ******************************************************************************************************/
#include <Chipcon\srf04\halsrf04.h>
#include <Chipcon\srf04\ebsrf04.h>
#include <intrins.h>




//-------------------------------------------------------------------------------------------------------
//  This file contains all necessary defines, macroes and function for writing to the LCD display.
//  The i2c communication is done using SMBus interrupt and timer 0 is used to generate SCL.
//  Below is an example on how to write a text to the display. As, showed below, only two of the 
//  functions in this file, (ebLcdInit and ebLcdUpdate) is needed to be called from the user application.
//  The other functions are only used internally in this file.
//
//      void ebLcdInit(void)
//      BYTE ebLcdUpdate(UINT8 *pLine1, UINT8 *pLine2)
//      void SMBusIsr(void) interrupt INUM_SMB0
//      BYTE ebLcdConvertChar(BYTE c)
//      void ebI2CHandler(void)
//
//  ebLcdInit();
//  ebLcdUpdate("Connecting", "      Smarter");
//
//  |---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
//  | C | o | n | n | e | c | t | i | n | g |   |   |   |   |   |   |
//  |---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---| 
//  |   |   |   |   |   |   | S | m | a | r | t | e | r |   |   |   |
//  |---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
// Status vector (SMBus) - top 4 bits only
#define SMB_MTSTA   0xE0    // (MT) start transmitted
#define SMB_MTDB    0xC0    // (MT) data byte transmitted, ACK received
#define SMB_MRDB    0x80    // (MR) data byte received

// Defines used by the ebLcdInit and ebLcdUpdate functions 
#define LINE_SIZE  16
#define LINE1      0x80
#define LINE2      0xC0
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
// LCD slave address
#define LCD_ADDR        0x76

// Defines for Register Select (RS). RS selects the register to be accessed for read and write
#define RS_0            0x00        // RS = 0 => selects instruction register for write and busy flag
                                    // and address counter for read
#define RS_1            0x40        // RS = 1 => selects the data register for both read and write

// Reset pin
#define RESET_N         P2_3

#define SPACE           0x9B
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
// Struct used by the ebLcdUpdate
typedef struct {
    BOOL doTransfer;
    BOOL transferInProgress;
    UINT8 bytesLeft;
    UINT8 position;
} I2C_DATA;
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
// Variables used by ebLcdInit, ebLcdUpdate, and the SMBus ISR 
BYTE i2cBuffer[47];       // It takes 47 bytes to update the entire LCD display
I2C_DATA i2cData;
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
//  DESCRIPTION:
//      Converts ASCII characters to the character set the LCD display uses 
//-------------------------------------------------------------------------------------------------------
BYTE ebLcdConvertChar(BYTE c);




//-------------------------------------------------------------------------------------------------------
//  DESCRIPTION: 
//      This function is responsible for all traffic on the I2C interface.
//-------------------------------------------------------------------------------------------------------
void ebI2CHandler(void);




//-------------------------------------------------------------------------------------------------------
//  void ebLcdInit(void)
//
//  DESCRIPTION:
//      Function used to initialize the LCD display. The SMBus uses timer 0 to generate SCL
//      This function also writes 32 SPACE characters to the display to clear it.
//-------------------------------------------------------------------------------------------------------
void ebLcdInit(void) {

    UINT8 i;

    // Setup SCL High and Low times using timer 0 (THighMin = TLowMin = 1 / fClockSourceOverflow)
    TH0 = 150;  // SCL low time = (256 - 150) * (1 / 24000000) = 4,42 us 
    TL0 = TH0;
  
    // Set mode
    TMOD &= 0xFC;
    TMOD |= MODE_2;     // 8-bit counter/timer with auto-reload
   
    CKCON |= BM_T0M;    // Counter/Timer 0 uses the system clock
    
    TIMER0_RUN(TRUE);   // Start timer 0    

    // Initialize SMBus 
    SMB0CF |= BM_ENSMB;

     // Enable SMBus interrupt
    INT_ENABLE(INUM_SMB0, INT_ON);
    ENABLE_GLOBAL_INT(TRUE);

    // Initializes the I2C handler's data structure
    i2cData.doTransfer = FALSE;
    i2cData.transferInProgress = FALSE;
    i2cData.position = 0;

    // Reset the display
    RESET_N = 0;
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    _nop_();
    RESET_N = 1;
 
    i2cBuffer[0] = 7;
    i2cBuffer[1] = LCD_ADDR;
    i2cBuffer[2] = RS_0;            // Instruction Register
    i2cBuffer[3] = 0x0C;            // Display control          D = 1:      Display On
                                    //                          C = 0:      Cursor Off
                                    //                          B = 0:      Cursor character blink off
    i2cBuffer[4] = 0x21;            // Function set             H = 1:      Use extended instruction set
    i2cBuffer[5] = 0xA0;            // Set DDRAM address        ADD = 0x20
    i2cBuffer[6] = 0x07;            // Display configuration    P = 1:      Column data right to left
                                    //                          Q = 1:      Row data, bottom to top
    i2cBuffer[7] = 0x24;            // Function set             DL = 0:     4 bits
                                    //                          M = 1:      2-line by 16 display
                                    //                          SL = 0:     MUX1:18
                                    //                          H = 0:      Use basic instruction set
    i2cBuffer[8] = 0;
    i2cData.doTransfer = TRUE;
    ebI2CHandler();
    while (i2cData.doTransfer == TRUE);     // Wait for tranfer to finish
    
    // Clear display by writing SPACE
    i2cBuffer[0] = 3;
    i2cBuffer[1] = LCD_ADDR;
    i2cBuffer[2] = RS_0;
    i2cBuffer[3] = LINE1;

    i2cBuffer[4] = 18;
    i2cBuffer[5] = LCD_ADDR;
    i2cBuffer[6] = RS_1;

    for (i = 0; i < (LINE_SIZE); i++)
        i2cBuffer[i + 7] = SPACE;

    i2cBuffer[23] = 3;
    i2cBuffer[24] = LCD_ADDR;
    i2cBuffer[25] = RS_0;
    i2cBuffer[26] = LINE2;

    i2cBuffer[27] = 18;
    i2cBuffer[28] = LCD_ADDR;
    i2cBuffer[29] = RS_1;

    for (i = 0; i < (LINE_SIZE); i++)
        i2cBuffer[i + 30] = SPACE;

    i2cBuffer[46] = 0;