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Better Algorithm for driving Custom LCD?

 
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SugarD
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Better Algorithm for driving Custom LCD?
PostPosted: Wed Dec 23, 2009 11:13 pm     Reply with quote
Hi, I am using PIC 18F65J90, which has built in LCD driver, to drive custom designed LCD that consists of multiple digits of 7 segment LCD's.

The LCD displays not only the numbers but also some letters that I can display using 7 segments.

When one uses module LCD, I know he can display multiple letters on the module using relatively small ROM space. He can just write,

Code:

lcd_putc("AbCdEF");

However, when I have to write the same thing on the custom LCD, I have to write
Code:

lcd_symbol(digit_map[A], digit1);
   lcd_symbol(digit_map[b], digit2);
   lcd_symbol(digit_map[c], digit3);
   lcd_symbol(digit_map[d], digit4);
   lcd_symbol(digit_map[E], digit5);
   lcd_symbol(digit_map[F], digit6);

which takes too much program memory if i want to put a lot of them.

Is there any way I do the same compactly with costing less program memory??

Thanks
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Wed Dec 23, 2009 11:25 pm     Reply with quote
Please don't start a new thread every time you have a new question on
using the 18F65J90 with 7-segment LCDs.

But to answer your question, look at the lcd_putc() function in this CCS
example file:
Quote:
c:\program files\picc\examples\ex_92lcd.c

Also look at the lcd_putc() function in this post:
http://www.ccsinfo.com/forum/viewtopic.php?t=32774&start=8

If you have any questions, add them to this thread or your earlier thread.
SugarD
Guest
i tried but..
PostPosted: Thu Dec 24, 2009 1:49 am     Reply with quote
Sorry, I thought that the two topics were different.

I looked at the post you referred and modified them to suit my purpose, which didn't work.

Code:

//main.c
#include<18F65J90.h>
#include<def_18F65J90.h>

#fuses intrc

#use delay(clock = 32000)
#define CLOCK_SPEED 32000



//****************DP*******G*********F*******E********D********C********B*******A*** 

#define DIGIT1 COM0+0,  COM2+31, COM3+31, COM1+31, COM0+31, COM1+0,  COM2+0,  COM3+0
#define DIGIT2 COM0+2,  COM2+1,  COM3+1,  COM1+1,  COM0+1,  COM1+2,  COM2+2,  COM3+2
#define DIGIT3 COM0+4,  COM2+3, COM3+3, COM1+3, COM0+3, COM1+4,  COM2+4,  COM3+4
#define DIGIT4 COM0+6,  COM2+5,  COM3+5,  COM1+5,  COM0+5,  COM1+6,  COM2+6,  COM3+6


const int8 DIGIT_MAP[10]= {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x27, 0x7F, 0x67};
//                       a      b    c     d     e     f     g       h     i       j
const int8 Letter_map[22] = {0x77, 0x7C, 0x39, 0x5E, 0X79, 0X71, 0X00, 0X00, 0X04, 0X00,
//                      k      l     m      n     o      p     q      r     s      t
                     0X00, 0X38, 0x00, 0x54, 0x5c, 0x73, 0x00, 0x50, 0x6d, 0x78,
//                     u      v
                     0x1c   0x3e};
//#including function headers.
#include<key_check.h>
int lcd_pos = 0;
byte segments = 0;
void lcd_putc(char c) {

      if(c=='\f')
       lcd_pos=0;
   else{
      if((c>='0')&&(c<='9'))
           segments=Digit_Map[c-'0'];
      else if((c>='a')&&(c<='z'))
         segments = Letter_Map[c - 'a'];
      else if(c=='-')
         segments = 0x40;
      else if(c =' ')
         segments = 0x00;
   }
   
      switch(lcd_pos){
        case 1 : lcd_symbol(segments,DIGIT1); break;
        case 2 : lcd_symbol(segments,DIGIT2); break;
        case 3 : lcd_symbol(segments,DIGIT3); break;
        case 4 : lcd_symbol(segments,DIGIT4); break;
         }
   lcd_pos++;
}


//Function used for initializing LCD
void LCD_init(void){
   LCDPS = 0b0010100;      //WFT = 0(Type A waveform), BIASMD = 0(1/4 bias),
                     //LCDA = 1(lcd drive module is active), WA = 1(write allowed), LP = 0000(prescaling = 8:1)
   //LCDSEx definition
      LCDSE0 = 0xFF;   //SEG<7:0> All Segment control
      LCDSE1 = 0B10011111; //SEG<15:8> do not use 11(pulse_out)
      LCDSE2 = 0XFF; //SEG<23:16>   All segment control
      LCDSE3 = 0B11011101;      //SEG<31:24>
      LCDSE4 = 0B00000001;
   
   //LCDCON setup
   LCDCON = 0b10011011;   // LCDEN = 1, /SLPEN = 1, WERR = 0,unimplemented, CS<1:0> = 00(Fosc/4), LMUX<1:0> = 11(use 4 commons)
   LCDREG = 0B00111100;//Unemplemented, CPEN = 0, BIAS<2:0> = 111, MODE13 = 1, CKSEL<1:0> = 00(regulator disabled)s
 
}
void init_rtn(void){
lcd_init();
}

void main(void){
   init_rtn();
   printf(lcd_putc,"\fabcd");
   while(1);            
}

When I run the code, the LCD only displays the first letter.
I think there is something wrong with my printf statement.
Thanks
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