Weird problem in my lcd 16*2

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hi i am trying to work on an lcd. I' m using avr studio 4. i have attached lcd.h and lcd.c in my project from peter fluffy. it displays a simple text in proteus. i connected the circuit accordingly. i burnt it in my atmega32. but it doesn't show text. when i connect the usbasp programmers ground with the ground of mcu, it works and displays the text. when i remove programmers ground, the text is gone. this is like a problem to me( don't mind, no offense).

i'm very much tired . can't get any solution . please help

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Last Edited: Tue. Jun 5, 2012 - 02:17 PM
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i also connected vss to gnd, vdd to 5v, vee to pot

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this is the code

</p>
<p>// AVR ATMEGA32 - INTERNAL 4MHz CLK</p>
<p>// Include Files<br />
#include <avr/io.h><br />
#include <avr/interrupt.h><br />
#include <stdlib.h><br />
#include <util/delay.h><br />
#include "lcd.h"	//	THE LCD HEADER FILE TO INCLUDE</p>
<p>// For Bitvise Operation Simplification Defines<br />
#define CLR(port,pin)	PORT ## port &= ~(1<<pin)<br />
#define SET(port,pin)	PORT ## port |=  (1<<pin)<br />
#define TOGL(port,pin)	PORT ## port ^=  (1<<pin)<br />
#define READ(port,pin)	PIN  ## port &   (1<<pin)<br />
#define OUT(port,pin)	DDR  ## port |=  (1<<pin)<br />
#define IN(port,pin)	DDR  ## port &= ~(1<<pin)</p>
<p>int main(void){<br />
// LCD<br />
OUT(A,4); OUT(A,5); OUT(A,6);	// RS - RW - E<br />
lcd_init(LCD_DISP_ON);<br />
lcd_clrscr();<br />
lcd_puts("Testing.. 1.2.3...");<br />
}<br />
[code]

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#ifndef LCD_H
#define LCD_H
/*************************************************************************
 Title	:   C include file for the HD44780U LCD library (lcd.c)
 Author:    Peter Fleury   http://jump.to/fleury
 File:	    $Id: lcd.h,v 1.13.2.2 2006/01/30 19:51:33 peter Exp $
 Software:  AVR-GCC 3.3
 Hardware:  any AVR device, memory mapped mode only for AT90S4414/8515/Mega
***************************************************************************/

/**
 @defgroup pfleury_lcd LCD library
 @code #include  @endcode
 
 @brief Basic routines for interfacing a HD44780U-based text LCD display

 Originally based on Volker Oth's LCD library,
 changed lcd_init(), added additional constants for lcd_command(), 
 added 4-bit I/O mode, improved and optimized code.
       
 Library can be operated in memory mapped mode (LCD_IO_MODE=0) or in 
 4-bit IO port mode (LCD_IO_MODE=1). 8-bit IO port mode not supported.

 Memory mapped mode compatible with Kanda STK200, but supports also 
 generation of R/W signal through A8 address line.
       
 @author Peter Fleury pfleury@gmx.ch http://jump.to/fleury
 
 @see The chapter Interfacing a HD44780 Based LCD to an AVR
      on my home page.

*/

/*@{*/

#if (__GNUC__ * 100 + __GNUC_MINOR__) < 303
#error "This library requires AVR-GCC 3.3 or later, update to newer AVR-GCC compiler !"
#endif

#include 
#include 

/** 
 *  @name  Definitions for MCU Clock Frequency
 *  Adapt the MCU clock frequency in Hz to your target. 
 */
#define XTAL 4000000              /**< clock frequency in Hz, used to calculate delay timer */


/**
 * @name  Definition for LCD controller type
 * Use 0 for HD44780 controller, change to 1 for displays with KS0073 controller.
 */
#define LCD_CONTROLLER_KS0073 0  /**< Use 0 for HD44780 controller, 1 for KS0073 controller */

/** 
 *  @name  Definitions for Display Size 
 *  Change these definitions to adapt setting to your display
 */
#define LCD_LINES           2     /**< number of visible lines of the display */
#define LCD_DISP_LENGTH    16     /**< visibles characters per line of the display */
#define LCD_LINE_LENGTH  0x40     /**< internal line length of the display    */
#define LCD_START_LINE1  0x00     /**< DDRAM address of first char of line 1 */
#define LCD_START_LINE2  0x40     /**< DDRAM address of first char of line 2 */
#define LCD_START_LINE3  0x14     /**< DDRAM address of first char of line 3 */
#define LCD_START_LINE4  0x54     /**< DDRAM address of first char of line 4 */
#define LCD_WRAP_LINES      0     /**< 0: no wrap, 1: wrap at end of visibile line */


#define LCD_IO_MODE      1         /**< 0: memory mapped mode, 1: IO port mode */
#if LCD_IO_MODE
/**
 *  @name Definitions for 4-bit IO mode
 *  Change LCD_PORT if you want to use a different port for the LCD pins.
 *
 *  The four LCD data lines and the three control lines RS, RW, E can be on the 
 *  same port or on different ports. 
 *  Change LCD_RS_PORT, LCD_RW_PORT, LCD_E_PORT if you want the control lines on
 *  different ports. 
 *
 *  Normally the four data lines should be mapped to bit 0..3 on one port, but it
 *  is possible to connect these data lines in different order or even on different
 *  ports by adapting the LCD_DATAx_PORT and LCD_DATAx_PIN definitions.
 *  
 */
#define LCD_PORT         PORTA        /**< port for the LCD lines   */
#define LCD_DATA0_PORT   LCD_PORT     /**< port for 4bit data bit 0 */
#define LCD_DATA1_PORT   LCD_PORT     /**< port for 4bit data bit 1 */
#define LCD_DATA2_PORT   LCD_PORT     /**< port for 4bit data bit 2 */
#define LCD_DATA3_PORT   LCD_PORT     /**< port for 4bit data bit 3 */
#define LCD_DATA0_PIN    0            /**< pin for 4bit data bit 0  */
#define LCD_DATA1_PIN    1            /**< pin for 4bit data bit 1  */
#define LCD_DATA2_PIN    2            /**< pin for 4bit data bit 2  */
#define LCD_DATA3_PIN    3            /**< pin for 4bit data bit 3  */
#define LCD_RS_PORT      LCD_PORT     /**< port for RS line         */
#define LCD_RS_PIN       4            /**< pin  for RS line         */
#define LCD_RW_PORT      LCD_PORT     /**< port for RW line         */
#define LCD_RW_PIN       5            /**< pin  for RW line         */
#define LCD_E_PORT       LCD_PORT     /**< port for Enable line     */
#define LCD_E_PIN        6            /**< pin  for Enable line     */

#elif defined(__AVR_AT90S4414__) || defined(__AVR_AT90S8515__) || defined(__AVR_ATmega64__) || \
      defined(__AVR_ATmega8515__)|| defined(__AVR_ATmega103__) || defined(__AVR_ATmega128__) || \
      defined(__AVR_ATmega161__) || defined(__AVR_ATmega162__)
/*
 *  memory mapped mode is only supported when the device has an external data memory interface
 */
#define LCD_IO_DATA      0xC000    /* A15=E=1, A14=RS=1                 */
#define LCD_IO_FUNCTION  0x8000    /* A15=E=1, A14=RS=0                 */
#define LCD_IO_READ      0x0100    /* A8 =R/W=1 (R/W: 1=Read, 0=Write   */
#else
#error "external data memory interface not available for this device, use 4-bit IO port mode"

#endif


/**
 *  @name Definitions for LCD command instructions
 *  The constants define the various LCD controller instructions which can be passed to the 
 *  function lcd_command(), see HD44780 data sheet for a complete description.
 */

/* instruction register bit positions, see HD44780U data sheet */
#define LCD_CLR               0      /* DB0: clear display                  */
#define LCD_HOME              1      /* DB1: return to home position        */
#define LCD_ENTRY_MODE        2      /* DB2: set entry mode                 */
#define LCD_ENTRY_INC         1      /*   DB1: 1=increment, 0=decrement     */
#define LCD_ENTRY_SHIFT       0      /*   DB2: 1=display shift on           */
#define LCD_ON                3      /* DB3: turn lcd/cursor on             */
#define LCD_ON_DISPLAY        2      /*   DB2: turn display on              */
#define LCD_ON_CURSOR         1      /*   DB1: turn cursor on               */
#define LCD_ON_BLINK          0      /*     DB0: blinking cursor ?          */
#define LCD_MOVE              4      /* DB4: move cursor/display            */
#define LCD_MOVE_DISP         3      /*   DB3: move display (0-> cursor) ?  */
#define LCD_MOVE_RIGHT        2      /*   DB2: move right (0-> left) ?      */
#define LCD_FUNCTION          5      /* DB5: function set                   */
#define LCD_FUNCTION_8BIT     4      /*   DB4: set 8BIT mode (0->4BIT mode) */
#define LCD_FUNCTION_2LINES   3      /*   DB3: two lines (0->one line)      */
#define LCD_FUNCTION_10DOTS   2      /*   DB2: 5x10 font (0->5x7 font)      */
#define LCD_CGRAM             6      /* DB6: set CG RAM address             */
#define LCD_DDRAM             7      /* DB7: set DD RAM address             */
#define LCD_BUSY              7      /* DB7: LCD is busy                    */

/* set entry mode: display shift on/off, dec/inc cursor move direction */
#define LCD_ENTRY_DEC            0x04   /* display shift off, dec cursor move dir */
#define LCD_ENTRY_DEC_SHIFT      0x05   /* display shift on,  dec cursor move dir */
#define LCD_ENTRY_INC_           0x06   /* display shift off, inc cursor move dir */
#define LCD_ENTRY_INC_SHIFT      0x07   /* display shift on,  inc cursor move dir */

/* display on/off, cursor on/off, blinking char at cursor position */
#define LCD_DISP_OFF             0x08   /* display off                            */
#define LCD_DISP_ON              0x0C   /* display on, cursor off                 */
#define LCD_DISP_ON_BLINK        0x0D   /* display on, cursor off, blink char     */
#define LCD_DISP_ON_CURSOR       0x0E   /* display on, cursor on                  */
#define LCD_DISP_ON_CURSOR_BLINK 0x0F   /* display on, cursor on, blink char      */

/* move cursor/shift display */
#define LCD_MOVE_CURSOR_LEFT     0x10   /* move cursor left  (decrement)          */
#define LCD_MOVE_CURSOR_RIGHT    0x14   /* move cursor right (increment)          */
#define LCD_MOVE_DISP_LEFT       0x18   /* shift display left                     */
#define LCD_MOVE_DISP_RIGHT      0x1C   /* shift display right                    */

/* function set: set interface data length and number of display lines */
#define LCD_FUNCTION_4BIT_1LINE  0x20   /* 4-bit interface, single line, 5x7 dots */
#define LCD_FUNCTION_4BIT_2LINES 0x28   /* 4-bit interface, dual line,   5x7 dots */
#define LCD_FUNCTION_8BIT_1LINE  0x30   /* 8-bit interface, single line, 5x7 dots */
#define LCD_FUNCTION_8BIT_2LINES 0x38   /* 8-bit interface, dual line,   5x7 dots */


#define LCD_MODE_DEFAULT     ((1<<LCD_ENTRY_MODE) | (1<<LCD_ENTRY_INC) )



/** 
 *  @name Functions
 */


/**
 @brief    Initialize display and select type of cursor
 @param    dispAttr \b LCD_DISP_OFF display off\n
                    \b LCD_DISP_ON display on, cursor off\n
                    \b LCD_DISP_ON_CURSOR display on, cursor on\n
                    \b LCD_DISP_ON_CURSOR_BLINK display on, cursor on flashing             
 @return  none
*/
extern void lcd_init(uint8_t dispAttr);


/**
 @brief    Clear display and set cursor to home position
 @param    void                                        
 @return   none
*/
extern void lcd_clrscr(void);


/**
 @brief    Set cursor to home position
 @param    void                                        
 @return   none
*/
extern void lcd_home(void);


/**
 @brief    Set cursor to specified position
 
 @param    x horizontal position\n (0: left most position)
 @param    y vertical position\n   (0: first line)
 @return   none
*/
extern void lcd_gotoxy(uint8_t x, uint8_t y);


/**
 @brief    Display character at current cursor position
 @param    c character to be displayed                                       
 @return   none
*/
extern void lcd_putc(char c);


/**
 @brief    Display string without auto linefeed
 @param    s string to be displayed                                        
 @return   none
*/
extern void lcd_puts(const char *s);


/**
 @brief    Display string from program memory without auto linefeed
 @param    s string from program memory be be displayed                                        
 @return   none
 @see      lcd_puts_P
*/
extern void lcd_puts_p(const char *progmem_s);


/**
 @brief    Send LCD controller instruction command
 @param    cmd instruction to send to LCD controller, see HD44780 data sheet
 @return   none
*/
extern void lcd_command(uint8_t cmd);


/**
 @brief    Send data byte to LCD controller 
 
 Similar to lcd_putc(), but without interpreting LF
 @param    data byte to send to LCD controller, see HD44780 data sheet
 @return   none
*/
extern void lcd_data(uint8_t data);


/**
 @brief macros for automatically storing string constant in program memory
*/
#define lcd_puts_P(__s)         lcd_puts_p(PSTR(__s))

/*@}*/
#endif //LCD_H
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So how have you tried to analyze the problem, do you have access to an oscilloscope or can you measure some pin high and pin low voltages with a multimeter? Do you know if the AVR runs any code at all when LCD is blank?

It is a weird problem. The actual circuit would be better than the virtual circuit because it lacks so many things.

It might have something to do with reset pin.

Since the LCD is on analog port, I would suggest to double check you have connected all GND and VCC pins, including AVCC and AGND, but just connecting the grounds together would not solve that.

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can't upload lcd.c

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i found now when i connect ground of programmer to the mcu ground(from a 13 v supply to 7805), pa5 and pa6 are 0 volts. when i remove the ground they become high. why?? i don't know.

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mechaboy wrote:
i found now when i connect ground of programmer to the mcu ground(from a 13 v supply to 7805), pa5 and pa6 are 0 volts. when i remove the ground they become high. why?? i don't know.

The LCD has internal pull-ups on RS and RW pins, so if the AVR is in reset or otherwise not configured these pins as low outputs, these pins (and LCD data pins) will float high. The E pin does not have an internal pull-up, so it will float at indeterminate state (which is why a pull-down resistor on E would be a good idea).

I think your AVR is in reset when RS and RW are high.

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This might be just my second post to these forums, but....
Please clean up your language, then more people may be tempted to help.

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I got the problem man, i am a dumb ass. you are right, thank you very much. the problem was in the Reset pin. I continued to connect the MOSI,MISO,SCK,RESET and GROUND pins for burning codes easily. That's why i didn't notice that i am creating problems by connecting a wire between Reset of my mcu and the programmers reset pin.
i removed it and it has finally solved. :)
one thing more, what can i do with the reset pin? i know it is used for burning code,but what more?
do it like starting the while loop again in programming? suppose i made a counter to count ir reflections ,project is object counter. say it counted 39 objects. if i connect a push button with reset and connect it to 5v , after pressing button willl the count be again from 0?

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Now please edit the thread title to remove the profanity.

Regards,
Steve A.

The Board helps those that help themselves.

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aferris2 wrote:
This might be just my second post to these forums, but....
Please clean up your language, then more people may be tempted to help.

thanks man for your suggestion. i was so tired and frustated that i couldn't resist using those languages. Maybe i should be more patient.

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Edit your first post. You can correct your 'spelling' in the title.

David.

p.s. Thankyou. Spelling is much improved now !

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welcome :)

one thing more, what can i do with the reset pin of atmega32? i know it is used for burning code,but what more?
do it like starting the while loop again in programming? suppose i made a counter to count ir reflections ,project is object counter. say it counted 39 objects. if i connect a push button with reset and connect it to 5v , after pressing button willl the count be again from 0?

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I have edited your post above to remove the profanity. Use language like that again and next time I'll simply ask one of the admins to remove your account.

Moderator

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mechaboy wrote:
welcome :)

one thing more, what can i do with the reset pin of atmega32? i know it is used for burning code,but what more?
do it like starting the while loop again in programming? suppose i made a counter to count ir reflections ,project is object counter. say it counted 39 objects. if i connect a push button with reset and connect it to 5v , after pressing button willl the count be again from 0?

Yes it is like the reset button on your PC. It starts over the software execution from the beginning, and also puts a lot of the AVR guts into default power-up state.

The reset is active low though, so normally it floats at supply voltage (there is an internal pull-up resistance), and a pushbutton would connect it to ground momentarily.

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Jepael wrote:
mechaboy wrote:
welcome :)

one thing more, what can i do with the reset pin of atmega32? i know it is used for burning code,but what more?
do it like starting the while loop again in programming? suppose i made a counter to count ir reflections ,project is object counter. say it counted 39 objects. if i connect a push button with reset and connect it to 5v , after pressing button willl the count be again from 0?

Yes it is like the reset button on your PC. It starts over the software execution from the beginning, and also puts a lot of the AVR guts into default power-up state.

The reset is active low though, so normally it floats at supply voltage (there is an internal pull-up resistance), and a pushbutton would connect it to ground momentarily.

Thank you.

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A very important clarification:

A "floating" pin is literally that - there is no driver or resistor applying voltage to it. This means that the pin is being affected by voltage (energy, actually) from picked up radio waves from A/C lighting (florescent lights are notorious for this), running AC and DC motors, switching power supplies, etc.

Even static electricity easily affects floating pin voltages. If the pin isn't being read by the AVR code then noise-induced logic states won't matter. A pullup or pulldown resistor cures the radio wave noise problem. They can set the default logic state if the line is driven by an open collector or tristate driver such as AVR pins configured to be like tristate drivers that allow other devices drive a signal line at times. The current pushed into a pulldown resistor or pulled from a pullup resistor by any type of driver easily overrides ("swamps out") the much weaker picked up ("induced") radio noise voltages.

A typical driver, like most AVR pins configured to be outputs, always apply a very strong logic voltage, either a high or a low , each which easily override the relatively "weak" voltage applied by a pullup or pulldown and the even weaker noise-induced voltages. However, when the MCU comes out of reset most of the IO pins are reconfigured by the reset to be inputs (!) until their PORT DDR bits are programmed to make them outputs. This is the most common cause of unintentional "floating inputs" in circuits.

Most AVR pins have a weak 40K to 50K ohm pullup resistor, effectively, that is attached by default to most AVR IO pins unless your DDR code specifically disables them. Simply reconfiguring the pins to become inputs does NOT disable those built-in pullups. These pullups may or may not be strong enough to swamp out picked up excess radio noise. It all depends on the location of the electronic components relative to sources of the radio noise. Using 10K ohm pullup or pulldown resistors is usually effective for most circuits - unless its in a very electrically "noisy" environment. Resistors on relatively long lengths of wires/cables should use resistors with lower values. These long wire lengths, unfortunately, are very effective radio frequency receiver antennas !

Another good reason to use pullups or pulldowns, unrelated to noise problems, is that some devices (like LCD modules) may get "confused" by a floating signal line when the MCU first comes out of reset. Many devices have a dedicated reset line that will return the device to a known good state even if it previously got "confused" by random voltage changes on its input control lines. The case in point is that line-based LCD modules do NOT have a reset input pin, which is very unfortunate for us and a poor design for many reasons. That's why it's a good idea to attach a pulldown resistor to the EN pin and ground (Ground is "VSS" in LCD terminology - go figure...).

That 50K ohm built-in pullup resistor inside the AVR pin may not be strong enough to overcome the radio frequency noise, especially if the distance from an AVR-to-LCD cable is over a foot long or it's located in a noisy environment.