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Charles Linquist
Joined: 07 May 2005
Posts: 28
Location: Campbell, CA
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| Another LCD question |
 Posted: Sat Jun 04, 2005 6:24 pm |
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I have been trying to modify Mark's LCDD.c example for my application, but so far without much success.
I'm using a 18F8720
The data lines are H0->H3
R/W is connected to H4
RS is connected to H5
Enable is connected to J2
I am including the pin assignment part of Mark's code, and have commented out his original.
Can someone tell me what I'm doing wrong?
| Code: |
struct lcd_pin_map
{
// ---------------------------- Mark's --------------------------
// 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
//-------------------- End of Mark's ----------------------
// --------------------- Mine --------------------------------
int unusedA;
int unusedB;
int unusedC;
int unusedD;
int unusedE;
int unusedF;
int unusedG;
int data :4 ; //Pins H0-H3
BOOLEAN rw; //Pin H4
BOOLEAN rs; //Pin H5
int unusedH :2 ; // Rest of port H
BOOLEAN dummy; //J0
BOOLEAN dummy2; //J1
Boolean enable; //J2
int unusedJ :5; // Rest of port J
// ---------------------- End of Mine ----------------------------
// ---------------------- Mark's ----------------------------
} lcd;
#if defined(__PCH__)
// #locate lcd = 0xF80 // Mark's
#locate lcd = 0xF87 // PortH // Mine
#else
#locate lcd = 5
#endif
struct lcd_tris_map
{
// -------------------- Mark's --------------------------------
// 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
// --------------------- End of Mark's -------------------------------
// ----------------------- Mine -----------------------------------------
int unusedA;
int unusedB;
int unusedC;
int unusedD;
int unusedE;
int unusedF;
int unusedG;
int data :4 ; //Pins H0-H3
BOOLEAN rw; //Pin H4
BOOLEAN rs; //Pin H5
int unusedH :2 ; // Rest of port H
int unusedI;
BOOLEAN dummy; //J0
BOOLEAN dummy2; //J1
Boolean enable; //J2
int unusedJ :5; // Rest of port J
// --------------- End of Mine ---------------------------
} lcdtris;
#if defined(__PCH__)
//#locate lcdtris = 0xF92 // Mark's
#locate lcdtris = 0XF99 // Mine
#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
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Posted: Sat Jun 04, 2005 6:46 pm |
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This is wrong
| Code: | #if defined(__PCH__)
// #locate lcd = 0xF80 // Mark's
#locate lcd = 0xF87 // PortH // Mine
#else
#locate lcd = 5
#endif |
It should be
| Code: |
#if defined(__PCH__)
#locate lcd = 0xF80 /
#else
#locate lcd = 5
#endif
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Since the lcd struct starts at port A
Change this
| Code: | #define set_tris_lcd(x) lcdtris.data = (x); lcdtris.control = 0;
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to
| Code: | #define set_tris_lcd(x) lcdtris.data = (x); lcdtris.rs=0;lcdtris.rw=0;lcdtris.enable=0;
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Charles Linquist
Joined: 07 May 2005
Posts: 28
Location: Campbell, CA
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| Posted: Sun Jun 05, 2005 10:55 am |
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I changed the code as you suggested. By looking at the .LST file I found another error that I had introduced, and I corrected that.
Still, the code doesn't work. I increased some delays, thinking that the display was slower than your model.
It still doesn't even light up the display.
I know the hardware works, PicBasicPro has no trouble running it.
(and does it with 4 lines of code - setup included!)
What could be wrong?
The calling program block:
delay_ms(100); \\Give the LCD time to start up
lcd_init(); \\ Initialize
delay_ms(100); \\ Wait some more
printf (lcd_putc("\fReady...")); \\ Show me the money
The modified driver:
| Code: |
struct lcd_pin_map
{
int unusedA;
int unusedB;
int unusedC;
int unusedD;
int unusedE;
int unusedF;
int unusedG;
int data :4 ; //Pins H0-H3
BOOLEAN rw; //Pin H4
BOOLEAN rs; //Pin H5
int unusedH :2 ; // Rest of port H
BOOLEAN dummy; //J0
BOOLEAN dummy2; //J1
Boolean enable; //J2
int unusedJ :5; // Rest of port J
} lcd;
#if defined(__PCH__)
#locate lcd = 0xF80
#else
#locate lcd = 5
#endif
struct lcd_tris_map
{
int unusedA;
int unusedB;
int unusedC;
int unusedD;
int unusedE;
int unusedF;
int unusedG;
int data :4 ; //Pins H0-H3
BOOLEAN rw; //Pin H4
BOOLEAN rs; //Pin H5
int unusedH :2 ; // Rest of port H
int unusedI;
BOOLEAN dummy; //J0
BOOLEAN dummy2; //J1
Boolean enable; //J2
int unusedJ :5; // Rest of port J
} lcdtris;
#if defined(__PCH__)
#locate lcdtris = 0xF92
#else
#locate lcdtris = 0x85
#endif
#define set_tris_lcd(x);lcdtris.data = (x); lcdtris.rs=0;lcdtris.rw=0;lcdtris.enable=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(5);
lcd.enable = 1;
delay_us(200);
lcd.enable = 0;
}
void lcd_send_byte( BYTE address, BYTE n ) {
lcd.rs = 0;
while ( bit_test(lcd_read_byte(),7) ) ;
lcd.rs = address;
delay_cycles(5);
lcd.rw = 0;
delay_cycles(5);
lcd.enable = 0;
lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}
void lcd_init() {
BYTE i;
set_tris_lcd(LCD_WRITE);
lcd.rs = 0;
lcd.rw = 0;
lcd.enable = 0;
delay_ms(15);
for(i=1;i<=3;++i) {
lcd_send_nibble(3);
delay_ms(5);
}
lcd_send_nibble(2);
for(i=0;i<=3;++i)
lcd_send_byte(0,LCD_INIT_STRING[i]);
}
void lcd_gotoxy( BYTE x, BYTE y) {
BYTE 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(4);
break;
case '\n' : lcd_gotoxy(1,2); break;
case '\b' : lcd_send_byte(0,0x10); break;
default : lcd_send_byte(1,c); break;
}
}
char lcd_getc( BYTE x, BYTE y) {
char value;
lcd_gotoxy(x,y);
lcd.rs=1;
value = lcd_read_byte();
lcd.rs=0;
return(value);
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Jun 05, 2005 3:45 pm |
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| Quote: | I'm using a 18F8720
The data lines are H0->H3
R/W is connected to H4
RS is connected to H5
Enable is connected to J2 |
The data sheet says this:
| Quote: | Note 1: On Power-on Reset, Port H pins
RH7:RH4 default to A/D inputs and read as ‘0’.
2: On Power-on Reset, Port H pins
RH3:RH0 default to system bus signals. |
So I would strongly question whether these pins are being re-configured
as digital i/o, or are they being left in their default state ?
CCS has sort of a "standard" of inserting startup code at the
beginning of main() to make all A/D pins be digital. But quite often
they don't do it correctly or completely. You didn't show us your
own initialization source code.
The data sheet further says this:
| Quote: |
Register ADCON1 configures RH7:RH4 as I/O or A/D
inputs. Register MEMCON configures RH3:RH0 as I/O
or system bus pins. |
So I think you should use #byte statements to define the addresses
of each of those registers, and then manually setup those registers
with code to configure your LCD pins as digital i/o. Refer to the data
sheet to get the addresses of those registers and also for the bit settings
necessary to configure those pins for digital i/o. |
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Charles Linquist
Joined: 07 May 2005
Posts: 28
Location: Campbell, CA
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| Posted: Sun Jun 05, 2005 8:32 pm |
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| That was it! Thanks! |
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