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csshah
Joined: 28 Feb 2005
Posts: 24
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| LCD interface on Port J |
 Posted: Fri Mar 18, 2005 12:10 pm |
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Hi all
I am interfacing LCD with PIC 18F8720 with CCS version 3.219 and I am using driver (4 bit interface) for 20x2 LCD given with the compiler. This driver uses pin A1,A2,A3 for control and lower nibble of port D for data. Now if I want to change the control pins to other port like J(J1,J2,J3) then what I need to change in order to do that. I changed the given code with address of port J and TRIS J but it didnt work. so can you tell me what else need to be changed.
| Code: |
////////////////////////////////////////////////////////////////////////////
//// LCDD.C ////
//// Driver for common LCD modules ////
//// ////
//// lcd_init() Must be called before any other function. ////
//// ////
//// lcd_putc(c) Will display c on the next position of the LCD. ////
//// The following have special meaning: ////
//// \f Clear display ////
//// \n Go to start of second line ////
//// \b Move back one position ////
//// ////
//// lcd_gotoxy(x,y) Set write position on LCD (upper left is 1,1) ////
//// ////
//// lcd_getc(x,y) Returns character at position x,y on LCD ////
//// ////
////////////////////////////////////////////////////////////////////////////
//// (C) Copyright 1996,1997 Custom Computer Services ////
//// This source code may only be used by licensed users of the CCS C ////
//// compiler. This source code may only be distributed to other ////
//// licensed users of the CCS C compiler. No other use, reproduction ////
//// or distribution is permitted without written permission. ////
//// Derivative programs created using this software in object code ////
//// form are not restricted in any way. ////
////////////////////////////////////////////////////////////////////////////
// This structure is overlayed onto the data ports so that you may use
// whatever ports you desire
struct lcd_pin_map
{
BOOLEAN dummy; // PinA0 is not used
BOOLEAN enable; // PinA1
BOOLEAN rw; // PinA2
BOOLEAN rs; // PinA3
int unusedA : 4; // The rest of portA
int unusedB; // portB is not used
int unusedC; // portC is not used
int data : 4; // lower nibble of portD is used for data lines
int unusedD : 4; // The rest of portD
} lcd;
#if defined(__PCH__)
#locate lcd = 0xF88 <--- here I made change in address for port J
#else
#locate lcd = 5
#endif
struct lcd_tris_map
{
BOOLEAN dummy; // PinA0 is not used
int control : 3;
int unusedA : 4; // The rest of portA
int unusedB; // portB is not used
int unusedC; // portC is not used
int data : 4; // lower nibble of portD is used for data lines
int unusedD : 4; // The rest of portD
} lcdtris;
#if defined(__PCH__)
#locate lcdtris = 0xF9A <-- here I changed address of tris port J
#else
#locate lcdtris = 0x85
#endif
#define set_tris_lcd(x) lcdtris.data = (x); lcdtris.control = 0;
#define lcd_type 2 // 0=5x7, 1=5x10, 2=2 lines
#define lcd_line_two 0x40 // LCD RAM address for the second line
BYTE const LCD_INIT_STRING[4] = {0x20 | (lcd_type << 2), 0xc, 1, 6};
// These bytes need to be sent to the LCD
// to start it up.
// The following are used for setting
// the I/O port direction register.
#define LCD_WRITE 0 // For write mode all pins are out
#define LCD_READ 15 // For read mode data pins are in
BYTE lcd_read_byte() {
BYTE low,high;
set_tris_lcd(LCD_READ);
lcd.rw = 1;
delay_cycles(1);
lcd.enable = 1;
delay_cycles(1);
high = lcd.data;
lcd.enable = 0;
delay_cycles(1);
lcd.enable = 1;
delay_us(1);
low = lcd.data;
lcd.enable = 0;
set_tris_lcd(LCD_WRITE);
return( (high<<4) | low);
}
void lcd_send_nibble( BYTE n ) {
lcd.data = n;
delay_cycles(1);
lcd.enable = 1;
delay_us(2);
lcd.enable=0;
} |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Posted: Fri Mar 18, 2005 12:46 pm |
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| is the data on port J as well? |
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csshah
Joined: 28 Feb 2005
Posts: 24
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Posted: Fri Mar 18, 2005 8:03 pm |
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Well then that's your problem!
| Code: |
// This structure is overlayed onto the data ports so that you may use
// whatever ports you desire
struct lcd_pin_map
{
int unusedA;
int unusedB;
int unusedC;
int data : 4; // lower nibble of portD is used for data lines
int unusedD : 4; // The rest of portD
int unusedE;
int unusedF;
int unusedG;
int unusedH;
BOOLEAN dummy;
BOOLEAN enable;
BOOLEAN rw;
BOOLEAN rs;
int unusedJ : 4;
} lcd;
#if defined(__PCH__)
#locate lcd = 0xF80
#else
#locate lcd = 5
#endif
struct lcd_tris_map
{
int unusedA;
int unusedB;
int unusedC;
int data : 4; // lower nibble of portD is used for data lines
int unusedD : 4; // The rest of portD
int unusedE;
int unusedF;
int unusedG;
int unusedH;
BOOLEAN dummy;
int control : 3;
int unusedJ : 4;
} lcdtris;
#if defined(__PCH__)
#locate lcdtris = 0xF92
#else
#locate lcdtris = 0x85
#endif
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csshah
Joined: 28 Feb 2005
Posts: 24
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| it works now!!! |
| Posted: Mon Mar 21, 2005 7:51 am |
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Hey Mark!!!
Thanks a lot man!! You r GREAT!!!
I really appreciate ur help.
take care |
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