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RatFink
Joined: 01 May 2004
Posts: 49
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| Problem with character position on an LCD |
 Posted: Wed May 19, 2004 2:36 am |
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Well, after finally getting my LCD to work, I found another small problem, here's the code.
| Code: | while (T0IF == 0); /* Stay in loop until T0IF sets */
lcd_gotoxy(0,2);
lcd_putc("TEMP");
/* Exit loop */
T0IF = 0; /* Clear the T0IF flag */
GO = 1; /* Start A/D conversion */
do
{;}
while (ADIF == 0 ); /* Wait for conversion to complete */
HEAT = ADRESH*(5.0/255)*100; /* Load HEAT with A/D value converted to volts, then degrees*/
lcd_gotoxy(5,2);
printf(lcd_putc, "%d", HEAT); |
I want to print the word "TEMP" at the first position on line 2, and the the value in "HEAT" at the 6th position of line 2 but for some reason The second value just keeps printing over the word TEMP. If I try it on line 1 it works fine.
I've looked though the driver I'm using but I just can't seem to find anything wrong. Here's the driver I'm using.
| Code: | //////////////////// LCD //////////////////////////////
// As defined in the following structure the pin connection is as follows:
// A1 enable
// A2 rw
// A3 rs
// D0 D4
// D1 D5
// D2 D6
// D3 D7
//
// LCD pins D0-D3 are not used and PIC D3 is not used.
//****************************************************************************************
#if defined(__PCH__)
#byte lcd = 0xF83 // This puts the entire structure
#else
#byte lcd = 8 // on to port D (at address 8)
#endif
//****************************************************************************************
#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.
// for 2 lines lcd: {0x0a,0xc,1,6}
// for 5x10 lcd: {0x06,0xc,1,6}
// for 5x7 lcd: {0x20,0xc,1,6}
// The following are used for setting
// the I/O port direction register.
//***** lcd command port *******************************************************************
struct lcd_command{
char none:1;
char enable:1;
char read_write:1;//rw
char data_command:1;//rs
};
struct lcd_command lcd_command_port;
#locate lcd_command_port=5
//---------------------------------------------------
struct lcd_data{
char data:4;
};
struct lcd_data lcd_data_port;
#locate lcd_data_port=8
//************ "COMMAND / DATA definition ************************************************************
#define COMMAND0 0
#define DATA1 1
//************ "READ / WRITE definition ************************************************************
#define WRITE0 0 //LCD <- MPU
#define READ1 1 //LCD -> MPU
//************ "E_UP / E_DOWN definition ************************************************************
#define E_DOWN 0
#define E_UP 1
//**********eeprom or flash******************************************************************************
#define EEPROM0 0 ;eeprom - not the program memory
#define FLASH1 1 ;program memory
//********* set tris d *********************************************************************
#define set_tris_lcd_read(){\
set_tris_a(TRISA & 0xf1/*0b11110001*/);\
set_tris_d(TRISD | 0x0f/*0b00001111*/);\
}
#define set_tris_lcd_write(){\
set_tris_a(TRISA & 0xf1/*0b11110001*/);\
set_tris_d(TRISD & 0xf0/*0b11110000*/);\
}
//*********** clear LCD ************************************
#define clear_lcd lcd_send_byte(0x1,COMMAND0);//clear lcd display
//****************************************************************************************
//************************************************************
char lcd_read_byte(void){
char low,high;
set_tris_lcd_read();
lcd_command_port.read_write = READ1;
delay_cycles(1);
lcd_command_port.enable = E_UP;
delay_cycles(1);
high = lcd_data_port.data & 0x0f;
lcd_command_port.enable = E_DOWN;
delay_cycles(1);
lcd_command_port.enable = E_UP;
delay_us(1);
low = lcd_data_port.data & 0x0f;
lcd_command_port.enable = E_DOWN;
set_tris_lcd_write();
return( (high << 4) | low);
}
//*************** - - *********************************************
void lcd_write_nibble(char temp_wr){
//Purpose:
lcd_data_port.data = temp_wr;
delay_cycles(1);
lcd_command_port.enable = 1;
delay_us(2);
lcd_command_port.enable = 0;
}
//*************** - - *********************************************
void lcd_send_byte(char data , char data_or_command ) {
lcd_command_port.data_command = COMMAND0;
while ( bit_test(lcd_read_byte(),7) ) ;
lcd_command_port.data_command = data_or_command;
delay_cycles(1);
lcd_command_port.read_write = WRITE0;
delay_cycles(1);
lcd_command_port.enable = E_DOWN;
lcd_write_nibble(data >> 4);
lcd_write_nibble(data & 0xf);
}
//************************************************************
void lcd_gotoxy( char location, char line) {//location 0...
char address;
if(line!=1)
address=40;//was80
else
address=0;
address+=location;
lcd_send_byte(0x80|address,COMMAND0);
}
//********** - 1 - **************************************************
void lcd_init(void){
//Purpose: initiate the lcd
//turnning PORTA0=analog, PORTA1-7=digital
ADCON1=0x0e;
//turnning command pin of lcd to output
set_tris_lcd_write();
//delay 15msec
delay_ms(15);
lcd_command_port.enable=0;
lcd_command_port.data_command=0;
lcd_command_port.read_write=0;
lcd_data_port.data=0;
delay_ms(2);
lcd_write_nibble(0x03);//was 30 ddram address: 1:1bit,line:1bit,address:4bit
delay_ms(10);//more then 4.1msec
lcd_write_nibble(0x03);//was 30
delay_us(150);//more then 100usec
lcd_write_nibble(0x03);//was 30
delay_us(100);
lcd_write_nibble(0x02);//was 20
while(bit_test(lcd_read_byte(),7));
lcd_send_byte(0x28,COMMAND0);//was 0x28 portd[3:0]=x2 then portd[3:0]=x8
// 4 bit low nibble, ddram address=0 first line
lcd_send_byte(0x0c,COMMAND0);//disp on
clear_lcd;
lcd_send_byte(0x6,COMMAND0);//entry inc
lcd_gotoxy(1,1);
}
//************************************************************
void lcd_putc( char c) {//this function works good
switch (c) {
case '\f' : lcd_send_byte(1,COMMAND0); delay_ms(2); break; //Clear display
case '\n' : lcd_gotoxy(1,2); break; //Go to start of second line
case '\b' : lcd_send_byte(0x10,COMMAND0); break; //Move back one position
default : lcd_send_byte(c,DATA1); break; //send the actual character
}
}
//*************** - - *********************************************
char lcd_getc( char location, char line) {
char value;
lcd_gotoxy(location,line);
while ( bit_test(lcd_read_byte(),7) ); // wait until busy flag is low
lcd_command_port.data_command=1;
value = lcd_read_byte();
lcd_command_port.data_command=0;
return(value);
return 1;
}
//************************************************************
//*************************----***********************************
void lcd_put_string(char *string){
//put string, starting from the curren cursor position
//assume that string not excides from lcd displayed RAM
char index=0;
while(string[index]!=0){
lcd_putc(string[index++]);
}
}
//************************************************************
void lcd_put_string_xy(char *string, char pos, char line){
//assume that string not excides from lcd displayed RAM
lcd_gotoxy(pos,line);
lcd_put_string(string);
}
//************************************************************
void stan_char(long *ptr,char line,char eeprom_or_flash){
//Purpose: write 16 chars, given in ptr location(eeprom or flash)
//to line of lcd, from the begining of the line
char c,i;
lcd_gotoxy(1,line);
/*OR: switch(line==1) {
case 1:lcd_send_byte(0x80,COMMAND); //initiate lcd to write to line 1
case 2:lcd_send_byte(0xc0,COMMAND); //initiate lcd to write to line 2
}*/
for (i=0;i<16;i++){
if (eeprom_or_flash)
c=read_program_eeprom(ptr+1);
else
c=read_eeprom((char)ptr+1);
lcd_putc(c);ptr++;
}
}
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I'm using a PIC16F877A
and a crystalFontz LCD with a HD44780 compatible controller
The Data sheet can be found here http://www.crystalfontz.com/products/0802a-color/CFAH0802AYMCJP.pdf
Can anybody please see if they can see something I don't see?
Thank you. |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Wed May 19, 2004 9:43 am |
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Here is a bit of code that I have used for several years in driving these types of displays. It is set up for a 16x2 display but has remarked code that can be used for a 16x1 display. Just change it around a little if you want to use a different port.
| Code: |
#include <string.h>
// Pinout connections for a 4 wire interface
//////////////////////
// LCD MCU
//////////////////////
// RS PIN_A5
// R/W PIN_E0
// E PIN_A4 -- this pin will need a pull-up resistor
// DB4 PIN_A0
// DB5 PIN_A1
// DB6 PIN_A2
// DB7 PIN_A3
#define RS PIN_A5 // RS pin of the LCD display
#define ENB PIN_A4 // enable for the LCD display
#define RW PIN_E0 // R/W bit for the LCD display
char table1[6] = {'L','I','N','E','1','\0'}; // "LINE1"
char table2[6] = {'L','I','N','E','2','\0'}; // "LINE2"
char text[10]; // general variable used to display information to the LCD display
void pulse(unsigned int8 bits) // sends out the clock pulse to the LCD display
{
unsigned int8 pp;
output_high(ENB);
output_a(bits);
for(pp = 0; pp < 10; pp++)
;
output_low(ENB);
}
void bf_check(void)
{
unsigned int8 pp;
int1 BF = 0;
set_tris_a(0x0F);// set bits 0-3 as inputs
output_low(RS);
output_high(RW);
for(pp = 0; pp < 5; pp++)
;
do
{
output_high(ENB);
for(pp = 0; pp < 10; pp++)
;
if(input(PIN_A3))
{
BF = 1;
}
else
{
BF = 0;
}
output_low(ENB);
for(pp = 0; pp < 5; pp++)
;
output_high(ENB);
for(pp = 0; pp < 10; pp++)
;
output_low(ENB);
}while(BF);
set_tris_a(0x00);// set all bits to outputs
}
void ctlnib(int8 niblet) // sends a control command to the LCD display
{
int8 msn, lsn;
bf_check();
msn = niblet & 0xF0;
msn = msn >> 4;
msn = msn | 0x10;
output_low(RW);
output_low(RS);
pulse(msn);
lsn = niblet & 0x0F;
lsn = lsn | 0x10;
pulse(lsn);
}
void datnib(int8 niblet) // sends a data byte to the LCD display
{
int8 msn, lsn;
bf_check();
msn = niblet & 0xF0;
msn = msn >> 4;
msn = msn | 0x30;
output_low(RW);
output_high(RS);
pulse(msn);
lsn = niblet & 0x0F;
lsn = lsn | 0x30;
pulse(lsn);
}
void disline(char outstr[], int8 dline) // format is; string - line
{ // displays a line of text on a 16 x 2 LCD display
int8 llg, dindex;
//int8 track; // add for a 16 x 1 display
// track = dline; // add for a 16 x 1 display
ctlnib(dline);
llg = strlen(outstr);
for(dindex = 0; dindex <= llg - 1; dindex++)
{
// if(track == 0x88) // add these 4 lines for a 16 x 1 display
// {
// ctlnib(0xC0);
// }
datnib(outstr[dindex]);
// track++; // add for a 16 x 1 display
}
}
void dischar(char outstr, int8 dline) // format is; character - position
{
ctlnib(dline);
datnib(outstr);
}
void clrdis(void) // clear the LCD display
{
ctlnib(0x01);
}
void initdisp(void) // initialize the LCD display
{
output_low(RW);
delay_ms(50);
pulse(0x03);
delay_ms(30);
pulse(0x03);
delay_us(400);
pulse(0x03);
pulse(0x02);
ctlnib(0x28);
ctlnib(0x80);
ctlnib(0x01);
ctlnib(0x06);
ctlnib(0x0C);
}// end of initdisp()
main()
{
initdisp();
// example commands to print text to display
/////////////////////////////////////////////
disline(table1, 0x80);// display on first line
disline(table2, 0xC0);// display on second line
sprintf(text, "%u", 100); // convert a number to be displayed on LCD
disline(text, 0x80); // now display that number on the display
}
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Ronald |
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RatFink
Joined: 01 May 2004
Posts: 49
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| Posted: Wed May 19, 2004 10:54 am |
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Thanks Ronald, I will check it out.
But can't one of you Ultra-Smart Coding Magicians see what could be causing the problem with the driver I'm using?
This seems like the part of the driver that applies
| Code: | void lcd_gotoxy( char location, char line) {//location 0...
char address;
if(line!=1)
address=40;//was80
else
address=0;
address+=location;
lcd_send_byte(0x80|address,COMMAND0);
}
|
And In my code
| Code: | lcd_gotoxy(0,2);
lcd_putc("TEMP");
lcd_gotoxy(5,2);
printf(lcd_putc, "%d", HEAT); |
It seems like I'm doing it right, but the second value keeps printing on top of the first at (0,2) instead of where it should be at (5,2). |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Wed May 19, 2004 11:02 am |
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Try using address 0x80 for the first line and 0xC0 for the second line. See what that does.
Ronald |
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RatFink
Joined: 01 May 2004
Posts: 49
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| Posted: Wed May 19, 2004 11:37 am |
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Well, I got it to work using
| Code: | lcd_gotoxy(0,2);
printf(lcd_putc, "TEMP %d", HEAT); |
I was just didn't want it to have to print the word TEMP through every loop. |
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Charlie U
Joined: 09 Sep 2003
Posts: 183
Location: Somewhere under water in the Great Lakes
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| Posted: Wed May 19, 2004 1:01 pm |
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After just a quick scan, in your lcd_gotoxy() function, shouldn't the address be in hex not decimal:
address = 0x40;
Just a thought?!?! |
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RatFink
Joined: 01 May 2004
Posts: 49
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| Posted: Wed May 19, 2004 1:02 pm |
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HMMM, I'll try that.
Thanks |
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