File content as of revision 0:5b8f0de660ec:

#include    <stdarg.h>
#include    "mbed.h"
#include    "I2cBusDevice.h"

//EastRising ERC1602-4 i2c display using ST7032i


//  i2c address
const char    ERC1602_4_addr = 0x7C;

//  initialization command sequence
const char    Comm_FunctionSet_Normal      = 0x38;
const char    Comm_FunctionSet_Extended    = 0x39;
const char    Comm_InternalOscFrequency    = 0x1C;
const char    Comm_ContrastSet             = 0x70;
const char    Comm_PwrIconContrast         = 0x57;
const char    Comm_FollowerCtrl            = 0x6C;
const char    Comm_DisplayOnOff            = 0x0C;
const char    Comm_ClearDisplay            = 0x01;
const char    Comm_EntryModeSet            = 0x04;
const char    Comm_ReturnHome              = 0x02;

//  general commands
const char    Comm_SetDDRAMAddress        = 0x80;
const char    DDRAMAddress_Ofst[]         = {0x00, 0x40};
const char    Comm_SetCGRAM               = 0x40;

//  setting values
const char    default_Contrast            = 0x35;
const char    COMMAND                     = 0x00;
const char    DATA                        = 0x40;
const char    MaxCharsInALine             = 0x10;    //buffer depth for one line (no scroll function used)
const char    init_seq0_length  = 7;
const char    init_seq0[ init_seq0_length ]
=    {
    Comm_FunctionSet_Normal,
    Comm_ReturnHome,             //This may be required to reset the scroll function
    Comm_FunctionSet_Extended,
    Comm_InternalOscFrequency,
    Comm_ContrastSet            | ( default_Contrast       & 0xF),
    Comm_PwrIconContrast        | ((default_Contrast >> 4) & 0x3),
    Comm_FollowerCtrl           | 0x0A,

};

const char    init_seq1_length  = 3;
const char    init_seq1[ init_seq1_length ]
=    {
    Comm_DisplayOnOff,
    Comm_ClearDisplay,
    Comm_EntryModeSet,
};

class TextLCD_ERC1602_4 : I2cBusDevice {
public:

    explicit TextLCD_ERC1602_4( I2C *LCD, char dev_address = ERC1602_4_addr, char *init_massage = NULL ) : I2cBusDevice( LCD, dev_address ) {
    restart();
    }
    ~TextLCD_ERC1602_4() {
    }

    void restart( void ) {      
       char *init_massage = NULL; 
        wait_ms(1);    //    interval after hardware reset
        for ( int i = 0; i < init_seq0_length; i++ ) {
            lcd_command( init_seq0[ i ] );
            wait_us(30);}
        for ( int i = 0; i < init_seq1_length; i++ ) {
            lcd_command( init_seq1[ i ] );}
        if ( init_massage )
            puts( 0, init_massage );
        set_CGRAM( 7, '\x1F' );
        curs[ 0 ]    = 0;
        curs[ 1 ]    = 0;
}

    void cls( void ) {
        lcd_command( Comm_ClearDisplay );
        wait_ms(2);
        curs[ 0 ]    = 0;
        curs[ 1 ]    = 0;
    }
    void put_custom_char( char c_code, const char *cg, char x, char y ) {
        for ( int i = 0; i < 5; i++ ) {
            set_CGRAM( c_code, cg );
            putcxy( c_code, x, y );
        }
    }
    
    void contrast( char contrast ) {
        lcd_command( Comm_FunctionSet_Extended );
        lcd_command( Comm_ContrastSet         |  (contrast     & 0x0f) );
        lcd_command( Comm_PwrIconContrast     | ((contrast>>4) & 0x03) );
        lcd_command( Comm_FunctionSet_Normal   );
    }

    void set_CGRAM( char char_code, const char* cg ) {
        for ( int i = 0; i < 8; i++ ) {
            lcd_command( (Comm_SetCGRAM | (char_code << 3) | i) );
            lcd_data( *cg++ );
        }
    }

    void set_CGRAM( char char_code, char v ) {
        char    c[ 8 ];
        for ( int i = 0; i < 8; i++ )
            c[ i ]    = v;
        set_CGRAM( char_code, c );
    }

    void putcxy( char c, char x, char y ) {
        if ( (x >= MaxCharsInALine) || (y >= 2) )
            return;

        lcd_command( (Comm_SetDDRAMAddress | DDRAMAddress_Ofst[ y ]) + x );
        lcd_data( c );
    }

    void putc( char line, char c ) {
        if ( (c == '\n') || (c == '\r') ) {
            clear_rest_of_line( line );
            curs[ line ]    = 0;
            return;
        }
        putcxy( c, curs[ line ]++, line );
    }

    void puts( char line, char *s ) {
        while ( char c    = *s++ )
            putc( line, c );
    }

    void printf( char line, char *format, ... ) {
        char        s[ 32 ];
        va_list        args;
        va_start( args, format );
        vsnprintf( s, 32, format, args );
        va_end( args );
        puts( line, s );
    }

private:
    char    curs[2];
    void clear_rest_of_line( char line ) {
        for ( int i = curs[ line ]; i < MaxCharsInALine; i++ )
            putcxy( ' ', i, line );
    }

    int lcd_write( char first, char second ) {
        char cmd[2];
        cmd[ 0 ]    = first;
        cmd[ 1 ]    = second;          
        return ( write( cmd, 2 ) );        
    }

    int lcd_command( char command ) {    
        return ( lcd_write( COMMAND, command ) );
    }
    int lcd_data( char data ) {
        return ( lcd_write( DATA, data ) );
    }
}
;