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2x8 LCD Secondline Problem

 
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koray_duran



Joined: 04 Feb 2010
Posts: 37

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2x8 LCD Secondline Problem
PostPosted: Thu Sep 29, 2011 1:12 am     Reply with quote

Hello,

I've trying to implement LCD to my project without success. I am using a 0802A - 2x8 LCD and flex_lcd library. It writes on first line without any problem but cant write on second line. I have checked out the ram adress for second line it is 0x40 also.

I wait your comments.

Code:

#include <18F67J60.h>
#fuses   HS, NOWDT, NOPROTECT, NOFCMEN, PRIMARY, NOETHLED
#use     delay(clock=25M)

#define MODBUS_TYPE                       MODBUS_TYPE_SLAVE
#define MODBUS_SERIAL_RX_BUFFER_SIZE      64
#define MODBUS_SERIAL_BAUD                9600
#define USE_WITH_PC                       1
#define POT                               PIN_F3
#define BUT                               PIN_B0
#define LED                               PIN_B4

#ifndef USE_WITH_PC
#define MODBUS_SERIAL_INT_SOURCE          MODBUS_INT_EXT
#define MODBUS_SERIAL_TX_PIN              PIN_C6   // Data transmit pin
#define MODBUS_SERIAL_RX_PIN              PIN_C7   // Data receive pin
//The following should be defined for RS485 communication
//#define MODBUS_SERIAL_ENABLE_PIN        0   // Controls DE pin for RS485
//#define MODBUS_SERIAL_RX_ENABLE         0   // Controls RE pin for RS485
#else
#define MODBUS_SERIAL_INT_SOURCE          MODBUS_INT_RDA
#endif

#include "modbus.c"
#include "flex_lcd.c"

#define MODBUS_ADDRESS 0x07

/*This function may come in handy for you since MODBUS uses MSB first.*/
int8 swap_bits(int8 c)
{
   return ((c&1)?128:0)|((c&2)?64:0)|((c&4)?32:0)|((c&8)?16:0)|((c&16)?8:0)
          |((c&32)?4:0)|((c&64)?2:0)|((c&128)?1:0);
}

void main()
{

   int8  coils = 0b00000101;
   int8  inputs = 0b00001001;
   int16 hold_regs[] = {0x8800,0x7700,0x6600,0x5500,0x4400,0x3300,0x2200,0x1100};
   int16 input_regs[] = {0x1100,0x2200,0x3300,0x4400,0x5500,0x6600,0x7700,0x8800};
   int16 event_count = 0;
   int16 potans = 0;
   int   adc = 0;
   
   setup_adc(ADC_CLOCK_INTERNAL);
   setup_adc_ports(PIN_F3);
   set_adc_channel(8);
   
   output_low(LED);
   
   modbus_init();
   lcd_init();
   lcd_putc("Test");
   lcd_gotoxy(1,2);
   lcd_putc("Koray");
   
   while(TRUE)
   {
      output_toggle(LED);
     
      adc = read_adc();
      potans = make16(adc,0x00);
      hold_regs[0] = potans;
     
      if(input(BUT)==0) { bit_set(inputs,5); }
      if(input(BUT)==1) { bit_clear(inputs,5); }
     
      //while(!modbus_kbhit());
     
      //check address against our address, 0 is broadcast
      if((modbus_rx.address == MODBUS_ADDRESS) || modbus_rx.address == 0)
      {
         switch(modbus_rx.func)
         {
            case FUNC_READ_COILS:    //read coils
            case FUNC_READ_DISCRETE_INPUT:    //read inputs
               if(modbus_rx.data[0] || modbus_rx.data[2] ||
                  modbus_rx.data[1] >= 8 || modbus_rx.data[3]+modbus_rx.data[1] > 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else
               {
                  int8 data;
                 
                  if(modbus_rx.func == FUNC_READ_COILS)
                     data = coils>>(modbus_rx.data[1]);      //move to the starting coil
                  else
                     data = inputs>>(modbus_rx.data[1]);      //move to the starting input

                  data = data & (0xFF>>(8-modbus_rx.data[3]));  //0 out values after quantity

                  if(modbus_rx.func == FUNC_READ_COILS)
                     modbus_read_discrete_input_rsp(MODBUS_ADDRESS, 0x01, &data);
                  else
                     modbus_read_discrete_input_rsp(MODBUS_ADDRESS, 0x01, &data);
                     
                  event_count++;
               }
               break;
            case FUNC_READ_HOLDING_REGISTERS:
            case FUNC_READ_INPUT_REGISTERS:
               if(modbus_rx.data[0] || modbus_rx.data[2] ||
                  modbus_rx.data[1] >= 8 || modbus_rx.data[3]+modbus_rx.data[1] > 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else
               {
                  if(modbus_rx.func == FUNC_READ_HOLDING_REGISTERS)
                     modbus_read_holding_registers_rsp(MODBUS_ADDRESS,(modbus_rx.data[3]*2),hold_regs+modbus_rx.data[1]);
                  else
                     modbus_read_input_registers_rsp(MODBUS_ADDRESS,(modbus_rx.data[3]*2),input_regs+modbus_rx.data[1]);
                 
                  event_count++;
               }
               break;
            case FUNC_WRITE_SINGLE_COIL:      //write coil
               if(modbus_rx.data[0] || modbus_rx.data[3] || modbus_rx.data[1] > 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else if(modbus_rx.data[2] != 0xFF && modbus_rx.data[2] != 0x00)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_VALUE);
               else
               {
                  //coils are stored msb->lsb so we must use 7-address
                  if(modbus_rx.data[2] == 0xFF)
                     bit_set(coils,7-modbus_rx.data[1]);
                  else
                     bit_clear(coils,7-modbus_rx.data[1]);

                  modbus_write_single_coil_rsp(MODBUS_ADDRESS,modbus_rx.data[1],((int16)(modbus_rx.data[2]))<<8);
                 
                  event_count++;
               }
               break;
            case FUNC_WRITE_SINGLE_REGISTER:
               if(modbus_rx.data[0] || modbus_rx.data[1] >= 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else
               {
                  //the registers are stored in little endian format
                  hold_regs[modbus_rx.data[1]] = make16(modbus_rx.data[3],modbus_rx.data[2]);

                  modbus_write_single_register_rsp(MODBUS_ADDRESS,
                               make16(modbus_rx.data[0],modbus_rx.data[1]),
                               make16(modbus_rx.data[2],modbus_rx.data[3]));
               }
               break;
            case FUNC_WRITE_MULTIPLE_COILS:
               if(modbus_rx.data[0] || modbus_rx.data[2] ||
                  modbus_rx.data[1] >= 8 || modbus_rx.data[3]+modbus_rx.data[1] > 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else
               {
                  int i,j;

                  modbus_rx.data[5] = swap_bits(modbus_rx.data[5]);

                  for(i=modbus_rx.data[1],j=0; i < modbus_rx.data[1]+modbus_rx.data[3]; ++i,++j)
                  { 
                     if(bit_test(modbus_rx.data[5],j))
                        bit_set(coils,7-i);
                     else
                        bit_clear(coils,7-i);
                  }

                  modbus_write_multiple_coils_rsp(MODBUS_ADDRESS,
                                 make16(modbus_rx.data[0],modbus_rx.data[1]),
                                 make16(modbus_rx.data[2],modbus_rx.data[3]));
                 
                  event_count++;
               }
               break;
            case FUNC_WRITE_MULTIPLE_REGISTERS:
               if(modbus_rx.data[0] || modbus_rx.data[2] ||
                  modbus_rx.data[1] >= 8 || modbus_rx.data[3]+modbus_rx.data[1] > 8)
                  modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_DATA_ADDRESS);
               else
               {
                  int i,j;

                  for(i=0,j=5; i < modbus_rx.data[4]/2; ++i,j+=2)
                     hold_regs[i] = make16(modbus_rx.data[j+1],modbus_rx.data[j]);

                  modbus_write_multiple_registers_rsp(MODBUS_ADDRESS,
                                 make16(modbus_rx.data[0],modbus_rx.data[1]),
                                 make16(modbus_rx.data[2],modbus_rx.data[3]));
               
                  event_count++;
               }
               break;           
            default:    //We don't support the function, so return exception
               modbus_exception_rsp(MODBUS_ADDRESS,modbus_rx.func,ILLEGAL_FUNCTION);
         }
      }
   }
}




flex_lcd library :
Code:

#define LCD_DB4   PIN_E0
#define LCD_DB5   PIN_D2
#define LCD_DB6   PIN_D0
#define LCD_DB7   PIN_E2

#define LCD_RS    PIN_C2
#define LCD_RW    PIN_E1
#define LCD_E     PIN_D1

// If you only want a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line.

#define USE_LCD_RW   1

//========================================

#define lcd_type        0    // 0=5x7, 1=5x10, 2=2 lines
#define lcd_line_two    0x40 // LCD RAM address for the 2nd line


BYTE const LCD_INIT_STRING[4] = {0x20 | (lcd_type << 2), 0xc, 1, 6};

//-------------------------------------
void lcd_send_nibble(int8 nibble)
{
// Note:  !! converts an integer expression
// to a boolean (1 or 0).
 output_bit(LCD_DB4, !!(nibble & 1));
 output_bit(LCD_DB5, !!(nibble & 2));
 output_bit(LCD_DB6, !!(nibble & 4));
 output_bit(LCD_DB7, !!(nibble & 8));

 delay_cycles(1);
 output_high(LCD_E);
 delay_us(2);
 output_low(LCD_E);
}

//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine.  For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.

#ifdef USE_LCD_RW
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3

retval = 0;

output_high(LCD_E);
delay_cycles(1);

retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);

output_low(LCD_E);

return(retval);
}
#endif

//---------------------------------------
// Read a byte from the LCD and return it.

#ifdef USE_LCD_RW
int8 lcd_read_byte(void)
{
int8 low;
int8 high;

output_high(LCD_RW);
delay_cycles(1);

high = lcd_read_nibble();

low = lcd_read_nibble();

return( (high<<4) | low);
}
#endif

//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte(int8 address, int8 n)
{
output_low(LCD_RS);

#ifdef USE_LCD_RW
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif

if(address)
   output_high(LCD_RS);
else
   output_low(LCD_RS);

 delay_cycles(1);

#ifdef USE_LCD_RW
output_low(LCD_RW);
delay_cycles(1);
#endif

output_low(LCD_E);

lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}

//----------------------------
void lcd_init(void)
{
int8 i;

output_low(LCD_RS);

#ifdef USE_LCD_RW
output_low(LCD_RW);
#endif

output_low(LCD_E);

delay_ms(15);

for(i=0 ;i < 3; i++)
   {
    lcd_send_nibble(0x03);
    delay_ms(5);
   }

lcd_send_nibble(0x02);

for(i=0; i < sizeof(LCD_INIT_STRING); i++)
   {
    lcd_send_byte(0, LCD_INIT_STRING[i]);

    // If the R/W signal is not used, then
    // the busy bit can't be polled.  One of
    // the init commands takes longer than
    // the hard-coded delay of 60 us, so in
    // that case, lets just do a 5 ms delay
    // after all four of them.
    #ifndef USE_LCD_RW
    delay_ms(5);
    #endif
   }

}

//----------------------------

void lcd_gotoxy(int8 x, int8 y)
{
int8 address;

if(y != 1)
   address = lcd_line_two;
else
   address=0;

address += x-1;
lcd_send_byte(0, 0x80 | address);
}

//-----------------------------
void lcd_putc(char c)
{
 switch(c)
   {
    case '\f':
      lcd_send_byte(0,1);
      delay_ms(2);
      break;

    case '\n':
       lcd_gotoxy(1,2);
       break;

    case '\b':
       lcd_send_byte(0,0x10);
       break;

    default:
       lcd_send_byte(1,c);
       break;
   }
}

//------------------------------
#ifdef USE_LCD_RW
char lcd_getc(int8 x, int8 y)
{
char value;

lcd_gotoxy(x,y);

// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7));

output_high(LCD_RS);
value = lcd_read_byte();
output_low(lcd_RS);

return(value);
}
#endif

void lcd_setcursor_vb(short visible, short blink) {
  lcd_send_byte(0, 0xC|(visible<<1)|blink);
}
Ttelmah



Joined: 11 Mar 2010
Posts: 19552

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PostPosted: Thu Sep 29, 2011 2:04 am     Reply with quote

Read the setup entries in the flex_lcd library.
What does the 22nd line say (18th line in what you posted, since you have removed the header line saying 'flex_lcd.h')?.
Do you think what you have will work for a two line display?....

Best Wishes
koray_duran



Joined: 04 Feb 2010
Posts: 37

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PostPosted: Thu Sep 29, 2011 3:13 am     Reply with quote

Ttelmah If i set it for 2 type. It doesn't even work. The contrast of LCD comes soo low that you can't see nothing even i set VEE to GND.

If i set it for 1 type It starts to work but still contrast not enough. And later if i set it for 0 contrast is allright. In all these tests VEE is directly connected to GND.

That was the reason to change type for 0. What can be problem ?
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Thu Sep 29, 2011 3:48 am     Reply with quote

18F67J60 suggests, that you are using VCC of 3.3V. In this case, VEE should be negative. If it's a W display type (= wide temperature range), correct VDD-VEE voltage is even above 5V according to the datasheet.
koray_duran



Joined: 04 Feb 2010
Posts: 37

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PostPosted: Thu Sep 29, 2011 6:07 am     Reply with quote

Still i didnt have change to try 5 volts but why contrast works fine in type 0 ? Do you have any idea ?

Edit : it works with 5 volts. Embarassed
Ttelmah



Joined: 11 Mar 2010
Posts: 19552

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PostPosted: Thu Sep 29, 2011 2:46 pm     Reply with quote

The reason the contrast is different with two lines selected, is that selecting one line, increases the refresh rate on the display. This is why if you boot up a display with the contrast set correctly for 2-line mode, and don't initialise it, you get a _really_ dark second line, and the first line also showing with much more contrast than normal.

Best Wishes
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