DIY exposure box timer PIC16f84 & 16x2 LCD

[insomartin]

^ I concur...
pero mas maganda din ang ESSAY!

[nucleus]

^ I concur...
pero mas maganda din ang ESSAY!

[su1c1d4l]

hello po...pwede po bang ma modify ung timer para sa hours:minutes na function sa PIC16F84A? bago lg kc ako sa assembly at PIC. my project aq na mag aactivate ng four AC lamps via relay switching sa pag ng 00:00 ang timer. thanx po sa tulong nyo..

[greentech]

mayroon  bang  datasheet ang 16x2 lcd display? I aadopt ko sana sa AVR.

[insomartin]

hello po...pwede po bang ma modify ung timer para sa hours:minutes na function sa PIC16F84A? bago lg kc ako sa assembly at PIC. my project aq na mag aactivate ng four AC lamps via relay switching sa pag ng 00:00 ang timer. thanx po sa tulong nyo..

yes pwede. but use a c or basic compiler para di ka mahirapan sa assembly.
proton basic, microelectronica C, hightech c, ccs c and many more.

mayroon  bang  datasheet ang 16x2 lcd display? I aadopt ko sana sa AVR.

http://en.wikipedia.org/wiki/HD44780_Character_LCD
meron mismong link sa wikipedia and a nice explaination too.

[arcturus_mengsk]

i made my own version... its not yet clean and may need improvement..

I used PIC16F628A and using its internal oscillator of 4Mhz.

here's the code using CCS C compiler version 4.093:

Code: [Select]

#include <16F628A.h>

#FUSES NOWDT,EC_IO,NOPUT,NOPROTECT

#use delay(clock=4000000)

#include "flex_LCD.c"

#define  START_STOP  (input(PIN_A2))
#define  SET         (input(PIN_A3))
#define  CLEAR       (input(PIN_A4))
#define  LED1        PIN_A0
#define  LED2        PIN_A1


//prototype
void title(void);
int16 set_timer(void);


//global variables
int1  timer0_flag;
int   timer_counter = 0;
int1  _LED1 = 0;


#int_TIMER0
void  TIMER0_isr(void)
{
   //4ms interrupt
   timer_counter++;
   if (timer_counter >= 250)
   {
      timer_counter = 0;
      timer0_flag = TRUE;        //timer0 flag every 1 sec.
      _LED1 ^= 1;
      output_bit(LED1,_LED1);
   }
}



void main()
{
   int16 seconds_counter;
   int   minutes;
   int   seconds;
   
   lcd_init();

   setup_oscillator(OSC_4MHZ);
   
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_16);     //overflow 4000us
   set_timer0(8);                               //just to be exact
   
   
   
   title();
   seconds_counter=set_timer();
   while(!START_STOP);
   enable_interrupts(INT_TIMER0);
   enable_interrupts(GLOBAL);

   while(TRUE)
   {
     
      if(timer0_flag)
      {
         timer0_flag = 0;
         
         output_high(LED2);
         
         seconds_counter--;

         minutes = seconds_counter/60;
         seconds = seconds_counter%60;
         lcd_gotoxy(8,1);
         printf(lcd_putc,"%02u:%02u",minutes,seconds);
         
         if(seconds_counter <= 0)
         {
            output_low(LED2);
            disable_interrupts(INT_TIMER0);
            disable_interrupts(GLOBAL);
            lcd_gotoxy(1,1);
            printf(lcd_putc,"    WERE DONE!");
         }
      }
     
      if (!START_STOP)
      {
         while(!START_STOP);
         output_low(LED2);
         output_low(LED1);
         disable_interrupts(INT_TIMER0);
         disable_interrupts(GLOBAL);
         lcd_gotoxy(1,1);
         printf(lcd_putc,"   INTERRUPTED!");
      }
   }

}

void title(void)
{
   //Start up Screen for 1 Sec
   lcd_gotoxy(1,1);
   printf(lcd_putc," <Exposure  Box>");
   lcd_gotoxy(1,2);
   printf(lcd_putc,"   [url=http://www.elab.ph]www.elab.ph[/url]");
   delay_ms(1000);
 
}

int16 set_timer(void)
{
   int16 set_counter = 0;
   int min,sec;
   set_counter = 0;
   printf(lcd_putc,"\f");
   lcd_gotoxy(1,1);
   printf(lcd_putc,"Timer: 00:00");
   lcd_gotoxy(1,2);
   printf(lcd_putc,"Timer Set: ");
   
   
   do{
     
      if(!SET)
      {
         while(!SET);
         set_counter += 30;
      }
     
      if(!CLEAR)
      {
         while(!CLEAR);
         set_counter = 0;
      }
     
      min = set_counter/60;
      sec = set_counter%60;

      lcd_gotoxy(12,2);
      printf(lcd_putc,"%02u:",min);
      lcd_gotoxy(15,2);
      printf(lcd_putc,"%02u",sec);
      delay_ms(100);
   }while(START_STOP);
   
   return set_counter;
   
}
the LCD driver:

Code: [Select]

// flex_LCD.c

// These pins are for the Microchip PicDem2-Plus board,
// which is what I used to test the driver.  Change these
// pins to fit your own board.

#define LCD_DB4   PIN_B0
#define LCD_DB5   PIN_B1
#define LCD_DB6   PIN_B2
#define LCD_DB7   PIN_B3

#define LCD_E     PIN_B4
#define LCD_RS    PIN_B5
#define LCD_RW    PIN_B6

// If you only want a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line.

//#define USE_LCD_RW   1     

//========================================

#define lcd_type 2        // 0=5x7, 1=5x10, 2=2 lines
#define lcd_line_two 0x40 // LCD RAM address for the 2nd line


int8 const LCD_INIT_STRING[4] =
{
 0x20 | (lcd_type << 2), // Func set: 4-bit, 2 lines, 5x8 dots
 0xc,                    // Display on
 1,                      // Clear display
 6                       // Increment cursor
 };
                             

//-------------------------------------
void lcd_send_nibble(int8 nibble)
{
// Note:  !! converts an integer expression
// to a boolean (1 or 0).
 output_bit(LCD_DB4, !!(nibble & 1));
 output_bit(LCD_DB5, !!(nibble & 2));
 output_bit(LCD_DB6, !!(nibble & 4));   
 output_bit(LCD_DB7, !!(nibble & 8));   

 delay_cycles(1);
 output_high(LCD_E);
 delay_us(2);
 output_low(LCD_E);
}

//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine.  For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.     

#ifdef USE_LCD_RW
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3

retval = 0;
   
output_high(LCD_E);
delay_cycles(1);

retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);
 
output_low(LCD_E);
   
return(retval);   
}   
#endif

//---------------------------------------
// Read a byte from the LCD and return it.

#ifdef USE_LCD_RW
int8 lcd_read_byte(void)
{
int8 low;
int8 high;

output_high(LCD_RW);
delay_cycles(1);

high = lcd_read_nibble();

low = lcd_read_nibble();

return( (high<<4) | low);
}
#endif

//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte(int8 address, int8 n)
{
output_low(LCD_RS);

#ifdef USE_LCD_RW
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif

if(address)
   output_high(LCD_RS);
else
   output_low(LCD_RS);
     
 delay_cycles(1);

#ifdef USE_LCD_RW
output_low(LCD_RW);
delay_cycles(1);
#endif

output_low(LCD_E);

lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}

//----------------------------
void lcd_init(void)
{
int8 i;

output_low(LCD_RS);

#ifdef USE_LCD_RW
output_low(LCD_RW);
#endif

output_low(LCD_E);

delay_ms(15);

for(i=0 ;i < 3; i++)
   {
    lcd_send_nibble(0x03);
    delay_ms(5);
   }

lcd_send_nibble(0x02);

for(i=0; i < sizeof(LCD_INIT_STRING); i++)
   {
    lcd_send_byte(0, LCD_INIT_STRING[i]);
   
    // If the R/W signal is not used, then
    // the busy bit can't be polled.  One of
    // the init commands takes longer than
    // the hard-coded delay of 60 us, so in
    // that case, lets just do a 5 ms delay
    // after all four of them.
    #ifndef USE_LCD_RW
    delay_ms(5);
    #endif
   }

}

//----------------------------

void lcd_gotoxy(int8 x, int8 y)
{
int8 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(2);
      break;
   
    case '\n':
       lcd_gotoxy(1,2);
       break;
   
    case '\b':
       lcd_send_byte(0,0x10);
       break;
   
    default:
       lcd_send_byte(1,c);
       break;
   }
}

//------------------------------
#ifdef USE_LCD_RW
char lcd_getc(int8 x, int8 y)
{
char value;

lcd_gotoxy(x,y);

// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7));

output_high(LCD_RS);
value = lcd_read_byte();
output_low(lcd_RS);

return(value);
}
#endif
and the proteus simulation:
http://www.4shared.com/file/140859129/5447482f/PicExposureBox.html

ok lng po ba pa ask how the program works and mga key points ng code. eto po kasi ginamit ko as timer circuit sa project. baka kc pag tinanung ako about the source code hindi ko masagot ng tama. thanks po

[marcelino]

ok lng po ba pa ask how the program works and mga key points ng code. eto po kasi ginamit ko as timer circuit sa project. baka kc pag tinanung ako about the source code hindi ko masagot ng tama. thanks po

tanong ko... nabasa mo na ba yung application notes (or yung datasheet) about TIMER0?
kung oo na, try to understand the,

Code: [Select]

setup_oscillator(OSC_4MHZ);
   
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_16);     //overflow 4000us
   set_timer0(8);                               //just to be exact
   
   
   
   title();
   seconds_counter=set_timer();
   while(!START_STOP);
   enable_interrupts(INT_TIMER0);
   enable_interrupts(GLOBAL);
.
.
.


next is the function,  int16 set_timer(void).

i suggest, you post your modified code on a new thread then dun na natin pag-usapan.

[obet19]

master marcelino ganun din po yun ginawa ko timer gaya ng post na diagram ni cute_worm,ala lumabas sa lcd ko black screen lang, ginamit ko 16F628A alam iba config pag 16F84 di kopa alam asm, ready hex file program to icprog lang prog alam ko. ano po ba gamit na hardware para gumaqa ng asm file at ano naman software ang gagamitin para naman matuto naman ako. pwede ba pagawa naman ng hex file he! he! thanks po uli. interesado po akong matuto.