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uni_student
Joined: 01 Aug 2007
Posts: 38
Location: AUckland, NEW ZEALAND
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| UART and GPS |
 Posted: Sun Dec 07, 2008 2:23 pm |
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Hi, trying to display GPS data on an LCD that start with"$P" or "$G" and all others discarded. For some reason I am still displaying other data such as"$F" and "$ ". GPS is working fine and LCD working fine , but somewhere in the code I am going wrong! Help appreciated, Cheers.
| Code: |
#include <18f452.h>
#include <string.h>
#fuses HS,NOLVP,NOWDT
#use delay (clock=20000000)
//
#use rs232 (baud=4800, xmit=PIN_C6, rcv=PIN_C7, parity=N, bits=8, ERRORS)
//
//Misc defines
#define GREEN_LED PIN_E2
//LCD defines
#define D0_LCD PIN_B0
#define D1_LCD PIN_B1
#define D2_LCD PIN_B2
#define D3_LCD PIN_B3
#define D4_LCD PIN_B4
#define D5_LCD PIN_B5
#define D6_LCD PIN_B6
#define D7_LCD PIN_B7
#define EN_LCD PIN_D6
#define RS_LCD PIN_D7
#define RW_LCD PIN_D5
#define TOP_LINE 0x80
#define BOTT_LINE 0xC0
#define CLEAR_DISP 0x01
#define RETURN_HOME 0x02
void LCD_INIT (int x);
void DATA_MANIP (unsigned int x);
void LCD_INIT (int x){
..........
}
void DATA_MANIP (unsigned int x){
output_high (EN_LCD);
output_bit ( D0_LCD, x & 0x01 );
output_bit ( D1_LCD, x & 0x02 );
output_bit ( D2_LCD, x & 0x04 );
output_bit ( D3_LCD, x & 0x08 );
output_bit ( D4_LCD, x & 0x10 );
output_bit ( D5_LCD, x & 0x20 );
output_bit ( D6_LCD, x & 0x40 );
output_bit ( D7_LCD, x & 0x80 );
output_low (EN_LCD);
}
//
void main (void){
char r;
int x, y;
LCD_INIT (0); //
x=0;
y=0;
while(TRUE){
r=getc();
if ((x>0)&&(x<15)){ //Display charactors to end of lcd display
x++;
DATA_MANIP (r);
} else if (x==15){ //End of display line
delay_ms(2000);
x=0;
if(y==0){
LCD_INIT (2); //Bottom Line
y=1;
} else{
LCD_INIT (1); //Top Line
y=0;
}
} else if ((r=='$')&&(x==0)){ //start of new gps data
r=getc();
if (r=='G') {
DATA_MANIP ('$');
DATA_MANIP ('G');
x++;
}
if (r=='P'){
DATA_MANIP ('$');
DATA_MANIP ('P');
x++;
}
} else{
x=0;
}
}
}
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Last edited by uni_student on Sun Dec 07, 2008 2:49 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Dec 07, 2008 2:38 pm |
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| Post the manufacturer and part number of your LCD. |
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uni_student
Joined: 01 Aug 2007
Posts: 38
Location: AUckland, NEW ZEALAND
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| Posted: Sun Dec 07, 2008 2:48 pm |
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| Quote: |
Post the manufacturer and part number of your LCD.
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Unsure of manufacturer of LCD (will check when home from work), but has Hitachi HD44780 driver in it. 16x2 LCD display, got it from futurlec.com. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Dec 07, 2008 2:51 pm |
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My suggestion is to use the flex LCD driver:
http://www.ccsinfo.com/forum/viewtopic.php?t=24661
Then you can call lcd_putc() to display a character, or use printf
to display a string (and re-direct the output of printf to lcd_putc).
It's much easier than your method. |
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FvM
Joined: 27 Aug 2008
Posts: 2337
Location: Germany
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| Posted: Sun Dec 07, 2008 4:28 pm |
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Although the code has long-winded actions, as the port B single bit output, it most likely doesn't keep the required timing according to HD44780 spec. With a parallel interface, it's easy to check the busy flag before writing to the display.
The single bit output can be replaced by a simple output_b(x); |
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