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Altera_Forum's avatar
Altera_Forum
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19 years ago

printing to 16x2 LCD module

i got this code from here (http://forum.niosforum.com/forum/index.php?showtopic=229). this code initialize the lcd module. 

#include <unistd.h># include <stdlib.h># include <stdio.h>
/* Commands which can be written to the COMMAND register */
enum /* Write to character RAM */
{
    LCD_CMD_WRITE_DATA = 0x80
    /* Bits 6:0 hold character RAM address */
};
enum /* Write to character generator RAM */
{
    LCD_CMD_WRITE_CGR = 0x40
    /* Bits 5:0 hold character generator RAM address */
};
enum /* Function Set command */
{
    LCD_CMD_FUNCTION_SET = 0x20,
    LCD_CMD_8BIT = 0x10,
    LCD_CMD_TWO_LINE = 0x08,
    LCD_CMD_BIGFONT = 0x04
};
enum /* Shift command */
{
    LCD_CMD_SHIFT = 0x10,
    LCD_CMD_SHIFT_DISPLAY = 0x08,
    LCD_CMD_SHIFT_RIGHT = 0x04
};
enum /* On/Off command */
{
    LCD_CMD_ONOFF = 0x08,
    LCD_CMD_ENABLE_DISP = 0x04,
    LCD_CMD_ENABLE_CURSOR = 0x02,
    LCD_CMD_ENABLE_BLINK = 0x01
};
enum /* Entry Mode command */
{
    LCD_CMD_MODES = 0x04,
    LCD_CMD_MODE_INC = 0x02,
    LCD_CMD_MODE_SHIFT = 0x01
};
enum /* Home command */
{
    LCD_CMD_HOME = 0x02
};
enum /* Clear command */
{
    LCD_CMD_CLEAR = 0x01
};
# define na_lcd_pio_command ((volatile int *) 0x80920850)# define na_lcd_pio_status ((volatile int *) 0x80920851)# define na_lcd_pio_wr_data ((volatile int *) 0x80920852)# define na_lcd_pio_rd_data ((volatile int *) 0x80920853)
# define PIO_LCD_IO_COMMAND (*na_lcd_pio_command)# define PIO_LCD_IO_STATUS (*na_lcd_pio_status)# define PIO_LCD_IO_WR_DATA (*na_lcd_pio_wr_data)# define PIO_LCD_IO_RD_DATA (*na_lcd_pio_rd_data)
void delay(int para)//delay for 0.2*para ms
{
    int i=0,j=0;
    for(i=0;i<para;i++)
  for(j=0;j<10000;j++);
}
int main()
{
    delay(75);
    PIO_LCD_IO_COMMAND=LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT;
    delay(21);
    PIO_LCD_IO_COMMAND=LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT | LCD_CMD_TWO_LINE;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_ONOFF;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_CLEAR;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_MODES | LCD_CMD_MODE_INC;
    delay(10);
    PIO_LCD_IO_COMMAND=LCD_CMD_ONOFF | LCD_CMD_ENABLE_DISP;
    delay(1000);
    return 0;
}

my question is: How to i print characters to the screen? i suppose i shud look for the address of the pins RS, R/W, and E. but i&#39;ve yet to locate them.

At the mean time, i&#39;m going thru pio_lcd16207.c and pio_lcd16207.h. i think i understand wat these codes r trying to do but i&#39;ve yet to come out with a prog tat works.

Pls advice. Thx in advance.

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    19 years ago

    i also tried to modified from pio_lcd16207.h. i merely add in the main function, change nr_delay to usleep. this time, nth happen to the lcd module. 

    #include <unistd.h># include "pio_lcd16207.h"# include "nios2_system.h"    /* Descriptions of standard peripherals */
static void delayShort(void);
// Device constants
// Internal LCD signals
enum{
    LCD_E  = 0x400,
    LCD_RS = 0x200,
    LCD_RW = 0x100,
    LCD_DATA = 0x0FF
};
// LCD Device Commands
enum{
    LCD_CMD_CLEAR = 0x01,
    LCD_CMD_HOME  =    0x02,
    LCD_CMD_MODES = 0x04,
    LCD_CMD_ONOFF = 0x08,
    LCD_CMD_SHIFT = 0x10,
    LCD_CMD_FUNC  = 0x20,
    LCD_CMD_RAMCGR= 0x40,
    LCD_CMD_RAMDDR= 0x80,
    LCD_CMD_FILLER= 0x00
};
// Device Parameters
enum{
    LCD_INTERFACE = 0x10,  // interface width;1 (8 BITS)/0 (4BITS)
    LCD_NUMROWS =    0x08,  //#  of display rows; 1 (2 ROWS)/0 (1ROW) 
    LCD_PIXEL    =    0x04,  // character pixel;    1(5x10 dots)/0 (5x7 dots)
    LCD_MOVE    =    0x02,  // character move direction; 1(increment)/0(decrement)
    LCD_SHIFT    =    0x01,  // move character with display shift; 1(shift)/0(no shift)
    LCD_DISP_SHIFT=    0x08  // action after character; 1(display shift)/0(character shift)
};
enum{
    LCD_COM_RESET = 0x30
};
// Some LCD parameters# define LCD_BUS_WIDTH 8# define LCD_PIXEL_WIDTH 5# define LCD_PIXEL_HEIGHT 8
// The hardcoded definition of where the LCD lives at 
// PIO port address
np_pio *lcd = 0;
void nr_pio_lcdcursorvisible(int bVisible)
{
    if(bVisible)
  nr_pio_lcdwritecommand(0x0E);
    else 
  nr_pio_lcdwritecommand(0x0C);
}
void nr_pio_lcdon(int bOn)
{
    if(bOn)
  nr_pio_lcdwritecommand(0x0C);
    else 
  nr_pio_lcdwritecommand(0x08);
}
void nr_pio_lcdclearscreen(void)
{
    nr_pio_lcdwritecommand(LCD_CMD_CLEAR);
}
void nr_pio_lcdsetcursor(int row, int col)
{
    unsigned char address;
    if(row > LCD_NUM_ROW)
  row = LCD_NUM_ROW;
    if(col > LCD_NUM_COL)
  col = LCD_NUM_COL;
    if(row == 0)
  address = 0;
    else if (row == 1)
  address = 0x40;
    else if (row == 2)
  address = 0x20;
    else
  address=0x60;
    address += col;
    nr_pio_lcdwritecommand(LCD_CMD_RAMDDR | address);
}
void nr_pio_lcdprintstringslowly(char *string, int time)
{
    char tempBuffer;
    int i;
    i=0;
    sprintf(tempBuffer, string);
    // Show as much of the string as we can...
    while(tempBuffer)
    {
  nr_pio_lcdwritecharacter(tempBuffer);
  usleep(time);
  i++;
    }
}
/*
 * nr_pio_lcdwritescreen(char *string);
 *
 * This is probably the most useful routine. It
 * takes a string, and prints it to the LCD starting
 * from the first character. If the string is less
 * than 32 characters, fill the rest of the display
 * with blanks. If the string exceeds 32 characters,
 * truncate it. So sorry!
 */
void nr_pio_lcdwritescreen(char *string)
{
    int row;
    int col;
    int done;
    int count;
    count=0;
    for(row=0; row < LCD_NUM_ROW; row++)
    {
  for(col=0; col < LCD_NUM_COL; col++)
  {
      nr_pio_lcdsetcursor(row,col);
      if(string == 0x00)    // hit the end and stick there.
    nr_pio_lcdwritecharacter(0xA0);
      else
    nr_pio_lcdwritecharacter(string);
  }
    }
}
void nr_pio_lcdinit(np_pio *lcdPio)
{
    static int beenInitialized;    // uninitialized static variables get cleared each run!
    if(beenInitialized)
  return;
    
    if(!lcdPio)
  lcdPio = (np_pio *)na_lcd_16207_0;    // pio in reference design...
    lcd = lcdPio;
    // Send first Reset
    usleep(15);    
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Send second Reset
    usleep(5);    
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Send third Reset
    usleep(1);
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Setup interface parameters: 8 bit bus, 2 rows, 5x7 font
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_FUNC | LCD_INTERFACE | LCD_NUMROWS);
    
    // Turn Display Off
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_ONOFF);
    // Clear Display
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_CLEAR);
    
    // Setup Default Mode
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_MODES | LCD_MOVE);
    //ON
    usleep(1);
    nr_pio_lcdon(1);
    
    beenInitialized = 1;
}
void nr_pio_lcdwritecommand(unsigned char command)
{
    // preserve the data on the lines, but clear the RS and RW line
    lcd->np_piodata=(lcd->np_piodata & ~(LCD_RS | LCD_RW | LCD_E));
    
    // output the RS and RW lines.. but nothing else
    lcd->np_piodirection=(lcd->np_piodirection | (LCD_RS | LCD_RW | LCD_E));
    delayShort();
    // toggle the E line HIGH to latch the command
    lcd->np_piodata=(lcd->np_piodata | LCD_E);
    delayShort();
    
    // output command word whilst E line is high
    lcd->np_piodata=(lcd->np_piodata & ~LCD_DATA);
    lcd->np_piodata=(lcd->np_piodata | command);
    lcd->np_piodirection=(lcd->np_piodirection | LCD_DATA);
    // toggle the E line LOW to latch the data
    lcd->np_piodata=(lcd->np_piodata & ~LCD_E);
    delayShort();
}
void nr_pio_lcdwritecharacter(unsigned char character)
{
    // preserve the data on the lines, but clear the RW and E line, set RS
    lcd->np_piodata=(lcd->np_piodata & ~(LCD_RW | LCD_E));
    lcd->np_piodata=(lcd->np_piodata | LCD_RS);
    
    // output the RS and RW lines.. but nothing else
    lcd->np_piodirection=(lcd->np_piodirection | (LCD_RW | LCD_E | LCD_RS));
    delayShort();
    // toggle the E line HIGH to latch the command
    lcd->np_piodata=(lcd->np_piodata | LCD_E);
    delayShort();
    
    // output command word whilst E line is high
    lcd->np_piodata=(lcd->np_piodata & ~LCD_DATA);
    lcd->np_piodata=(lcd->np_piodata | character);
    lcd->np_piodirection=(lcd->np_piodirection | LCD_DATA);
    // toggle the E line LOW to latch the data
    lcd->np_piodata=(lcd->np_piodata & ~LCD_E);
}
void delayShort(void)
{
    int i;
    int v = 0;
    for(i=0;i<50;i++)
  v++;
}  
int main(void)
{
    lcd = (np_pio *)na_lcd_16207_0;
    // Send first Reset
    usleep(15);
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Send second Reset
    usleep(5);    
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Send third Reset
    usleep(1);
    nr_pio_lcdwritecommand(LCD_COM_RESET);
    // Setup interface parameters: 8 bit bus, 2 rows, 5x7 font
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_FUNC | LCD_INTERFACE | LCD_NUMROWS);
    // Turn Display Off
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_ONOFF);
    // Clear Display
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_CLEAR);
    // Setup Default Mode
    usleep(1);
    nr_pio_lcdwritecommand(LCD_CMD_MODES | LCD_MOVE);
    //ON
    usleep(1);
    nr_pio_lcdon(1);
    printf("LCD initialized.\n");
    usleep(1000);
    nr_pio_lcdwritecharacter(&#39;A&#39;);
    printf("LCD written.\n");
    usleep(5000);
    return 0;
}

    Pls help! Thx!
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    19 years ago

    --- Quote Start ---

    originally posted by jwlam@Aug 28 2006, 04:04 AM

    i got this code from here (http://forum.niosforum.com/forum/index.php?showtopic=229). this code initialize the lcd module. 

    #include <unistd.h># include <stdlib.h># include <stdio.h>
/* commands which can be written to the command register */
enum /* write to character ram */
{
    lcd_cmd_write_data = 0x80
    /* bits 6:0 hold character ram address */
};
enum /* write to character generator ram */
{
    lcd_cmd_write_cgr = 0x40
    /* bits 5:0 hold character generator ram address */
};
enum /* function set command */
{
    lcd_cmd_function_set = 0x20,
    lcd_cmd_8bit = 0x10,
    lcd_cmd_two_line = 0x08,
    lcd_cmd_bigfont = 0x04
};
enum /* shift command */
{
    lcd_cmd_shift = 0x10,
    lcd_cmd_shift_display = 0x08,
    lcd_cmd_shift_right = 0x04
};
enum /* on/off command */
{
    lcd_cmd_onoff = 0x08,
    lcd_cmd_enable_disp = 0x04,
    lcd_cmd_enable_cursor = 0x02,
    lcd_cmd_enable_blink = 0x01
};
enum /* entry mode command */
{
    lcd_cmd_modes = 0x04,
    lcd_cmd_mode_inc = 0x02,
    lcd_cmd_mode_shift = 0x01
};
enum /* home command */
{
    lcd_cmd_home = 0x02
};
enum /* clear command */
{
    lcd_cmd_clear = 0x01
};
# define na_lcd_pio_command ((volatile int *) 0x80920850)# define na_lcd_pio_status ((volatile int *) 0x80920851)# define na_lcd_pio_wr_data ((volatile int *) 0x80920852)# define na_lcd_pio_rd_data ((volatile int *) 0x80920853)
# define pio_lcd_io_command (*na_lcd_pio_command)# define pio_lcd_io_status (*na_lcd_pio_status)# define pio_lcd_io_wr_data (*na_lcd_pio_wr_data)# define pio_lcd_io_rd_data (*na_lcd_pio_rd_data)
void delay(int para)//delay for 0.2*para ms
{
    int i=0,j=0;
    for(i=0;i<para;i++)
  for(j=0;j<10000;j++);
}
int main()
{
    delay(75);
    pio_lcd_io_command=lcd_cmd_function_set | lcd_cmd_8bit;
    delay(21);
    pio_lcd_io_command=lcd_cmd_function_set | lcd_cmd_8bit;
    delay(10);
    pio_lcd_io_command=lcd_cmd_function_set | lcd_cmd_8bit;
    delay(10);
    pio_lcd_io_command=lcd_cmd_function_set | lcd_cmd_8bit | lcd_cmd_two_line;
    delay(10);
    pio_lcd_io_command=lcd_cmd_onoff;
    delay(10);
    pio_lcd_io_command=lcd_cmd_clear;
    delay(10);
    pio_lcd_io_command=lcd_cmd_modes | lcd_cmd_mode_inc;
    delay(10);
    pio_lcd_io_command=lcd_cmd_onoff | lcd_cmd_enable_disp;
    delay(1000);
    return 0;
}

    my question is: how to i print characters to the screen? i suppose i shud look for the address of the pins rs, r/w, and e. but i&#39;ve yet to locate them.

    at the mean time, i&#39;m going thru pio_lcd16207.c and pio_lcd16207.h. i think i understand wat these codes r trying to do but i&#39;ve yet to come out with a prog tat works.

    pls advice. thx in advance.

    <div align='right'><{post_snapback}> (index.php?act=findpost&pid=17891)</div>

    --- Quote End ---

    this is regester map address,pls see linux driver book,could anyone post the lcd driver?thanks
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    19 years ago

    jwlam,

    have you got it working ? I am interested in this. Pls help me through.

    cheers