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peaps
Joined: 15 Sep 2008
Posts: 11
Location: Hemel Hempstead, Hertfordshire, UK
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 Posted: Sat Oct 04, 2008 10:40 am |
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I have found out what the problem is, and frankly, I am surprised that no one else has come across this before. This problem also exists with the CCS lcd.c driver that ships with the compiler.
The strange character is not due to '\n' but rather NULL CHARS at the end of strings.
When calling lcd_putc("Hello World");
a '\0' also gets sent at the end of the string which the LCD just outputs as garbage.
To get around this problem I have made a very small ammendment to the lcd_putc() function:
| Quote: | void lcd_putc( char c) {
switch (c) {
case '\f' : lcd_send_byte(0,1);
delay_ms(2);
break;
case '\n' : lcd_gotoxy(1,2); break;
case '\b' : lcd_send_byte(0,0x10); break;
// do nothing in case of Null char
case '\0' : break;
default : lcd_send_byte(1,c); break;
}
} |
Note the additional switch statement that handles null chars.
Andy Peaple |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sat Oct 04, 2008 12:31 pm |
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| Quote: | | 2. Compiler version: 4.013 |
Your version is at best, a Beta version of the vs. 4 compiler.
If your version has the bug that you describe, then it should display '00'
at the end of the output, with the test program shown below.
I don't have 4.013 to test, but vs. 4.014 and later, do not put a '00' at
the end. This is the output from a good version of the compiler:
| Quote: | | 48 65 6C 6C 6F 20 57 6F 72 6C 64 |
| Code: |
#include <16F877.H>
#fuses XT,NOWDT,NOPROTECT,BROWNOUT,PUT,NOLVP
#use delay (clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
void lcd_putc(char c)
{
printf("%X ", c);
}
//=================================
void main()
{
lcd_putc("Hello World");
while(1);
} |
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DavidW
Joined: 26 Oct 2008
Posts: 1
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| Posted: Sun Oct 26, 2008 3:50 pm |
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Hello PCM. I just want to say thanks for this custom LCD.C driver. I been having a tough time figuring out the CCS LCD driver since I am a beginner with PIC programming. I made some modifications to your original code to fit the I/O pins that were available on my PIC but when I compile the code I get an error
Error 128 "flex_lcd.c" Line 28(1,42): A #DEVICE required before this line
and the line with the error is in flex_lcd.c:
int8 const LCD_INIT_STRING[4] =
Do you know why I am getting this error?
I am using a PIC16F877A and a 2x16 HD44780 LCD display. Here are the only modifications I made to flex_lcd.c:
#define LCD_DB4 PIN_B4
#define LCD_DB5 PIN_B5
#define LCD_DB6 PIN_B6
#define LCD_DB7 PIN_B7
#define LCD_E PIN_C1
#define LCD_RS PIN_C2
#define LCD_RW PIN_C3
A little bit more information, I am using version 4.064 for the CCS C compiler. Thanks for your help! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Oct 26, 2008 4:19 pm |
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| Quote: | | A #DEVICE required before this line |
This type of question belongs in the main forum. If the following
information doesn't fix the problem, then post the question in the
main forum:
Are you using MPLAB ? If so, see these links:
How to use multiple source files with MPLAB:
http://www.ccsinfo.com/forum/viewtopic.php?t=34046
More detailed information on using multiple files with MPLAB.
Read all the links in this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=32221 |
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ishmael
Joined: 02 Jun 2009
Posts: 4
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| hello again |
| Posted: Tue Jun 02, 2009 3:05 pm |
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my question dissapeared.
can portA be used with this driver for a pic16f648A ? i port B is occupied with USART and 32khz.
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sat Jun 06, 2009 11:56 am |
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Read the instructions in the first post. Any pin can be used, provided
that it has full i/o capabilities. Don't use input-only pins. If the pin
is open-drain, then an external pull-up resistor must be used on that pin. |
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BotBoy
Joined: 06 Nov 2009
Posts: 6
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| Posted: Tue Nov 10, 2009 1:15 pm |
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| Code: | lcd_putc("\fHello World\n");
lcd_putc("Line Number 2"); |
Is possible after put these two lines on LCD...
write some word only on line 2 without clean line 1? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Nov 10, 2009 1:46 pm |
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| Quote: | Is possible after put these two lines on LCD...
write some word only on line 2 without clean line 1? |
Call the following function in the LCD driver to set the cursor position.
The Origin is (1, 1) and it's in the upper left corner of the LCD.
| Quote: | | void lcd_gotoxy(int8 x, int8 y) |
You can ask ordinary LCD questions (like this one) in the main forum. |
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yoda
Joined: 22 Dec 2009
Posts: 3
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| nothing happen |
| Posted: Tue Dec 29, 2009 5:06 am |
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i'm using your flex_lcd and test it using your prog:
| Code: | #include <16F877A.H>
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 20000000)
#include <lcd flex driver.c>
//==========================
void main()
{
lcd_init(); // Always call this first.
lcd_putc("\fHello World\n");
lcd_putc("Line Number 2");
while(1);
}
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| Code: | and change
#define LCD_DB4 PIN_C3
#define LCD_DB5 PIN_C2
#define LCD_DB6 PIN_C1
#define LCD_DB7 PIN_C0
#define LCD_E PIN_D0
#define LCD_RS PIN_D2
#define LCD_RW PIN_D1
//change bcause of wiring i already made
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It can be compiled and write to the pic but
nothing come up to the lcd. I checked the wiring and it all good.
I'm using pcw compiler and pic2kit. |
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yoda
Joined: 22 Dec 2009
Posts: 3
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| Posted: Thu Dec 31, 2009 1:23 am |
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Ok the problem can be solved by connecting my Vee pin to ground.
At first I connect it to the trimpot to vary the lcd contrast. Why is this happening?
_________________
help me to help you to help me |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Dec 31, 2009 1:59 am |
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| The normal setting for the LCD contrast is about 0.4 to 0.5 volts. |
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gonzalza
Joined: 23 Feb 2010
Posts: 12
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| Re: Flexible LCD driver |
| Posted: Tue Feb 23, 2010 5:43 pm |
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Hi PCM Programmer how are you? I noticed the forum is quite old but, I'm interested on it, well, I'm good at c language and assembly however I have never programmed pic with c language. That's why if I'm doing so simple questions excuse me about it.
In the first code I saw this " / These pins are for the Microchip PicDem2-Plus board, " and I don't understand this. In fact I just bought a lcd 16x2 and already install the CCS plugin to MPLAB.
But now what kind of board are you talking about? Without knowing this I can't continue. Thanks. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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gonzalza
Joined: 23 Feb 2010
Posts: 12
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| Posted: Wed Mar 03, 2010 4:32 pm |
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Dear PCM Programer
I want to test the LCD, but im not gonna work with the board from microchip and also i want to use the pic 16f874 or 877, 1.can i use the same port configuration PB and PA .
#define LCD_DB4 PIN_D0
#define LCD_DB5 PIN_D1
#define LCD_DB6 PIN_D2
#define LCD_DB7 PIN_D3
#define LCD_E PIN_A1
#define LCD_RS PIN_A3
#define LCD_RW PIN_A2
2. apart of it, i just have to use VDD and VSS Don't I? do i have to use another pin from LCD? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Mar 03, 2010 4:51 pm |
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1. Use any available PIC i/o pins. (That can do both input and output).
2. Set the contrast pin on the LCD to about 0.4 volts.
If you have any more questions on LCDs, post them in the main forum. |
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